A microcontroller comprising an oscillator configured to receive an external resonator signal

Abstract

Embodiments of the present disclosure relate to a microcontroller including an oscillator configured to receive an external resonator signal. A shared input / output unit pair is configured to be connectable to a first external resonator or a second external resonator. A first oscillator and a second oscillator are coupled to the shared input / output unit pair via a switching circuit. The switching circuit is configured to connect either the first oscillator or the second oscillator to the input / output unit pair.

Description

[0001] Priority claim

[0002] This application claims the priority benefit of French patent application No. 2000993, filed on January 31, 2020, the contents of which are incorporated herein by reference in their entirety to the fullest extent permitted by law. Technical Field

[0003] Embodiments relate to microcontrollers, and in particular to a microcontroller including an oscillator configured to receive an external resonator signal. Background Art

[0004] Microcontrollers are known that include multiple input / output unit pairs configured to be connected to external resonators. Specifically, each of these input / output unit pairs is configured to be connected to a single external resonator. These microcontrollers also include oscillators connected to these input / output unit pairs. Specifically, each oscillator is connected to a single input / output unit pair to receive a signal transmitted by the external resonator connected to the input / output unit pair.

[0005] More specifically, these microcontrollers include a high-frequency oscillator and a low-frequency oscillator. The high-frequency oscillator is connected to a first input / output unit pair, which is configured to be connected to a high-frequency external resonator. The low-frequency oscillator is connected to a second input / output unit pair, which is configured to be connected to a low-frequency external resonator.

[0006] Such microcontrollers need to allocate two pairs of input / output units for the operation of the high frequency oscillator and the operation of the low frequency oscillator.In addition, the two oscillators are not always used by the end user, who preferably selects only one of the two oscillators.

[0007] At the same time, in some applications, it is desirable to reduce the number of input / output units of a microcontroller. This reduction in the number of input / output units may result in the user using a resonator inside the microcontroller, which may not be as accurate as an external resonator.

[0008] Therefore, there is a need to provide a microcontroller configured to use two oscillators from two external resonators while reducing the number of input / output units allocated for the operation of the two oscillators.

[0009] Furthermore, using prior art microcontrollers, users are often limited in their choices regarding the design of a circuit board including the microcontroller and each external resonator. Specifically, the user's design choices are limited by the location of the input / output unit pairs configured to connect to the external resonators.

[0010] Therefore, there is also a need to provide a microcontroller that can provide greater flexibility in the choice of design of a circuit board including the microcontroller and an external resonator connected to the microcontroller. Summary of the Invention

[0011] According to one aspect, a microcontroller includes: at least one input / output unit pair, configured to be connected to a first external resonator; a first oscillator and a second oscillator; and at least one pair among the at least one input / output unit pair (referred to as a shared pair) is also configured to be connected to a second external resonator, the microcontroller also including: a switching circuit, located between the shared input / output unit pair and the first oscillator and the second oscillator, the switching circuit being configured to be able to connect either the first oscillator or the second oscillator to the shared input / output unit pair.

[0012] Such a microcontroller allows the end user to use the same input / output unit pair to advantageously use two external resonators.

[0013] Such a microcontroller also enables the number of input / output units dedicated to the use of an oscillator to be reduced. In particular, such a microcontroller allows one input / output unit pair to be shared for the use of two oscillators.

[0014] Specifically, in prior art microcontrollers, the use of two oscillators requires the allocation of two input / output unit pairs for the operation of the two oscillators. Therefore, the microcontroller according to the embodiments herein enables the number of input / output units dedicated to the use of the oscillators to be reduced relative to these known microcontrollers. Therefore, such a microcontroller enables the release of two input / output units. Then, the two released input / output units can be dedicated to another purpose.

[0015] Preferably, the microcontroller comprises a plurality of shared input / output unit pairs.

[0016] In particular, the user may select which pair of input / output units the resonator is to be connected to, depending on the desired position of the resonator on the circuit board including the microcontroller.

[0017] Such a microcontroller therefore enables greater flexibility in the choice of the design of the circuit board comprising the microcontroller and the external resonator.

[0018] Furthermore, preferably, the microcontroller includes a control unit configured to control the switching circuit so as to connect either the first oscillator or the second oscillator to the input / output unit pair.

[0019] In an advantageous embodiment, each shared input / output cell pair comprises a first cell acting as an output for the first resonator and the second resonator, and a second cell acting as an input for the first resonator and the second resonator.

[0020] In one advantageous embodiment, for each shared input / output cell pair, the switching circuit includes a path, referred to as a first main path, configured to: electrically connect the input of the first oscillator to the first input of the second cell in the shared pair; electrically connect the output of the first oscillator to the first output of the first cell in the shared pair; and wherein each first main path includes a switch between the first oscillator and the cell to which the first main path is connected.

[0021] The switches of the first main path connected to the same shared input / output cell pair may be controlled to a closed state in which they allow the first oscillator to be electrically connected to the same shared input / output cell pair.

[0022] The switches of the first main path connected to the same shared input / output cell pair may be controlled to an open state in which they allow the first oscillator to be electrically disconnected from the same shared input / output cell pair.

[0023] Specifically, the control unit can be configured to control the switch of each first main path connected to the same shared input / output unit pair to a closed state so as to be able to electrically connect the first oscillator to the first external resonator, which is connected to the shared input / output unit pair.

[0024] The control unit may also be configured to control the switch of each first main path connected to the same shared input / output unit pair to an off state so as to be able to disconnect the first oscillator from the first external resonator connected to the shared input / output unit pair.

[0025] In a preferred embodiment, for each shared input / output cell pair, the switching circuit further comprises a path, referred to as a second main path, configured to: electrically connect the input of the second oscillator to the second input of the second cell in the shared pair; electrically connect the output of the second oscillator to the second output of the first cell in the shared pair; and wherein each second main path comprises a switch between the second oscillator and the cell to which the second main path is connected.

[0026] The switches of the second main path connected to the same shared input / output cell pair may be controlled to a closed state in which they allow the second oscillator to be electrically connected to the same shared input / output cell pair.

[0027] The switches of the first main path connected to the same shared input / output cell pair may be controlled to an open state in which they allow the second oscillator to be electrically disconnected from the same shared input / output cell pair.

[0028] Specifically, the control unit can be configured to control the switch of each second main path connected to the same shared input / output unit pair to a closed state so as to be able to electrically connect the second oscillator to the second external resonator, which is connected to the shared input / output unit pair.

[0029] In addition, the control unit can be configured to control the switch of each second main path connected to the same shared input / output unit pair to an open state so as to be able to disconnect the second oscillator from the second external resonator connected to the shared input / output unit pair.

[0030] The control unit may be configured to control the switch to a closed state for either the first main path or for the second main path.

[0031] Specifically, the control unit may be configured such that when the switch of each second main path is controlled to be in an open state, the switch of each first main path is controlled to be in a closed state. Furthermore, the control unit may be configured such that when the switch of each first main path is controlled to be in an open state, the switch of each second main path is controlled to be in a closed state.

[0032] In a preferred embodiment, for each shared input / output cell pair, the switching circuit further comprises a path, referred to as a first secondary path, configured to: electrically connect the output of the first oscillator to the second output of the first cell in the shared pair; electrically connect the input of the first oscillator to the second input of the second cell in the shared pair; and wherein each first secondary path comprises a switch between the first oscillator and the cell to which the first secondary path is connected.

[0033] The first secondary path enables an end user to select which input / output unit of a pair of input / output units to connect the external resonator to the first oscillator.

[0034] The switches of the first secondary path connected to the same shared input / output cell pair may be controlled to a closed state in which they allow the first oscillator to be electrically connected to the same shared input / output cell pair.

[0035] The switches of the first secondary path connected to the same shared input / output cell pair may be controlled to an open state in which they allow the first oscillator to be electrically disconnected from the same shared input / output cell pair.

[0036] Specifically, the control unit can be configured to control the switch of each first secondary path connected to the same shared input / output unit pair to a closed state so as to be able to electrically connect the first oscillator to the second external resonator, which is connected to the shared input / output unit pair.

[0037] The control unit may also be configured to control the switch of each first secondary path connected to the same shared input / output unit pair to an off state so as to be able to disconnect the first oscillator from the second external resonator connected to the shared input / output unit pair.

[0038] Specifically, the control unit may be configured such that when the switch of each first secondary path is controlled to be in an open state, the switch of each first main path and second main path is controlled to be in a closed state.

[0039] Furthermore, the control unit may be configured such that when the switch of each first main path or the switch of each second main path is controlled to be in an open state, the switch of each first secondary path is controlled to be in a closed state.

[0040] In an advantageous embodiment, the switching circuit further comprises, for each shared input / output cell pair, a path, referred to as a first compensation path, which connects each first secondary path from a node arranged between the switch of the first secondary path and the input / output cell to which the first secondary path is connected to the first oscillator so as to form a feedback loop.

[0041] In a preferred embodiment, for each shared input / output cell pair, the switching circuit further comprises a path, referred to as a second secondary path, configured to: electrically connect the output of the second oscillator to the first output of the first cell; electrically connect the input of the second oscillator to the first input of the second cell; and wherein each second secondary path comprises a switch between the second oscillator and the cell to which the second secondary path is connected.

[0042] The second secondary path enables an end user to select which input / output unit of a pair of input / output units to connect the external resonator to the second oscillator.

[0043] The switches of the second secondary path connected to the same shared input / output cell pair may be controlled to a closed state in which they allow the first oscillator to be electrically connected to the same shared input / output cell pair.

[0044] The switches of the second secondary path connected to the same shared input / output cell pair may be controlled to an open state in which they allow the first oscillator to be electrically disconnected from the same shared input / output cell pair.

[0045] Specifically, the control unit can be configured to control the switch of each second secondary path connected to the same shared input / output unit pair to a closed state so as to be able to electrically connect the second oscillator to the first external resonator, which is connected to the shared input / output unit pair.

[0046] The control unit can also be configured to control the switch of each second secondary path connected to the same shared input / output unit pair to an open state so as to be able to disconnect the second oscillator from the first external resonator, which is connected to the shared input / output unit pair.

[0047] The control unit may be configured to control the switch of the first main path, the switch of the second main path, the switch of the first secondary path, or the switch of the second secondary path to a closed state.

[0048] Specifically, the control unit may be configured such that when the switch of each second secondary path is controlled to be in an open state, the switches of each first and second main paths and the switch of each first secondary path are controlled to be in a closed state.

[0049] Furthermore, the control unit may be configured such that when the switch of each first main path, the switch of each second main path, or the switch of each first secondary path is controlled to be in an open state, the switch of each second secondary path is controlled to be in a closed state.

[0050] In an advantageous embodiment, the switching circuit further comprises, for each shared input / output cell pair, a path, referred to as a second compensation path, connecting each second secondary path from a node arranged between the switch of the second secondary path and the input / output cell to which the second secondary path is connected to the second oscillator, so as to form a feedback loop.

[0051] Each oscillator is configured to deliver an oscillating signal exhibiting a given frequency based on a signal transmitted by a resonator operating at said given frequency.

[0052] In an advantageous embodiment, the first oscillator is configured to receive an oscillating signal having a frequency of approximately 32 kHz.The first oscillator is then a low frequency oscillator.

[0053] In an advantageous embodiment, the second oscillator is configured to receive an oscillating signal having a frequency between approximately 4 MHz and 50 MHz.The second oscillator is then a high-frequency oscillator.

[0054] In an advantageous embodiment, the switching circuit is configured to be 5V tolerant.

[0055] According to another aspect, a circuit board is proposed, comprising: a microcontroller such as described above; and an external resonator connected to a shared input / output unit pair of the microcontroller. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Other advantages and features of the present invention will become apparent upon examination of the detailed description of a complete non-limiting embodiment and the accompanying drawings, in which:

[0057] Figure 1 An embodiment of a microcontroller including two oscillators is shown;

[0058] Figure 2 An embodiment of a microcontroller including two oscillators is shown; and

[0059] Figures 3 to 6 Various connection configurations for a microcontroller are shown. DETAILED DESCRIPTION

[0060] Figure 1 A microcontroller MIC according to an embodiment is shown, which comprises two oscillators OSC2 , OCS2 .

[0061] The first oscillator OSC1 can be used as a low frequency oscillator configured to operate based on an oscillating electrical signal delivered by the low frequency external resonator RBF. Specifically, the first oscillator OSC1 is configured to receive an oscillating electrical signal having a frequency of approximately 32 kHz and amplify the oscillating signal.

[0062] The second oscillator OSC2 can be used as a high frequency oscillator configured to operate based on the electrical signal delivered by the high frequency external resonator RHF. Specifically, the second oscillator OSC2 is configured to receive an oscillating electrical signal having a frequency between 4 MHz and 50 MHz and amplify the oscillation signal.

[0063] The external resonators RBF, RHF may be connected to a pair of input / output units CEL1, CEL2 of the microcontroller.

[0064] exist Figure 1In the figure, only one input / output unit pair is shown for ease of understanding. However, multiple input / output unit pairs can be envisioned.

[0065] The pair of input / output units CEL1, CEL2 is configured to be connectable to a first external resonator and / or a second external resonator. The first resonator may be a low-frequency resonator RBF capable of delivering an oscillating electrical signal having a frequency of approximately 32 kHz. The second resonator may be a high-frequency external resonator RHF capable of delivering an oscillating electrical signal having a frequency between 4 MHz and 50 MHz.

[0066] The pair of input / output units CEL1 , CEL2 includes a first input / output unit CEL1 used as an output of the external resonator RBF, RHF in the following description and a second input / output unit CEL2 used as an input of the oscillator OSC1 , OSC2 in the following description.

[0067] Each resonator RBF, RHF may be connected so as to have a first terminal connected to cell CEL1 and a second terminal connected to cell CEL2.

[0068] Specifically, the unit CEL2 includes a first input PIN1 and a second input PIN2. The unit CEL1 includes a first output POUT1 and a second output POUT2.

[0069] The first resonator may be connected to the first input PIN1 of the cell CEL2 and the first output POUT1 of the cell CEL1 .

[0070] The second resonator may be connected to the second input PIN2 of the cell CEL2 and the second output POUT2 of the cell CEL1 .

[0071] Figure 1 The pair of input / output cells CEL1 , CEL2 shown in FIG is said to be shared, since it can be connected to two external resonators.

[0072] The microcontroller MIC further includes a switching circuit CC, one side of which is electrically connected to the oscillators OSC1, OSC2 and the other side of which is electrically connected to the pair of input / output cells CEL1, CEL2. Of course, it is possible to envision a switching circuit configured to be connected to a plurality of pairs of input / output cells, which may or may not be shared.

[0073] exist Figure 1 In the embodiment shown in , the switching circuit CC comprises:

[0074] A first input SIN1 configured to receive a signal OSCINLSE from an output of a first oscillator OSC1;

[0075] a first output SOUT1 configured to deliver a signal OSCOUTLSE to an input of a first oscillator OSC1;

[0076] a second input SIN2 configured to receive a signal OSCINHSE from an output of a second oscillator OSC2; and

[0077] The second output SOUT2 is configured to deliver the signal OSCOUTHSE to the input of the second oscillator OSC2.

[0078] The switching circuit also includes:

[0079] a third output SOUT3 connected to the first output POUT1 of the first input / output unit CEL1;

[0080] A third input SIN3 connected to the first input PIN1 of the second input / output unit CEL2;

[0081] a fourth output SOUT4 connected to the second output POUT2 of the first input / output unit CEL1; and

[0082] The fourth input SIN4 is connected to the second input PIN2 of the second input / output unit CEL2.

[0083] The switching circuit further comprises paths referred to as first main paths PCP1 , PCP2 for connecting the first oscillator OSC1 to the output POUT1 and the input PIN1 , respectively.

[0084] Specifically, the first main path PCP1 connects the first input SIN1 to the third output SOUT3 via the switch SW1a of the switching circuit CC. The first main path PCP2 connects the third input SIN3 to the first output SOUT1 via the switch SW2a of the switching circuit CC.

[0085] The switching circuit CC further comprises paths called second main paths DCP1 , DCP2 for connecting the second oscillator OSC2 to the output POUT2 and the input PIN2 , respectively.

[0086] Specifically, the second main path DCP1 connects the second input SIN2 to the fourth output SOUT4 via the switch SW3a of the switching circuit CC. The second main path DCP2 connects the fourth input SIN4 to the second output SOUT2 via the switch SW4a of the switching circuit CC.

[0087] The switching circuit further comprises paths referred to as first secondary paths PCS1 , PCS2 for connecting the first oscillator OSC1 to the output POUT2 and the input PIN2 , respectively.

[0088] Specifically, the first secondary path PCS1 connects the first input SIN1 to the fourth output SOUT4 through the switch SW1b of the switching circuit CC. The first secondary path PCS2 connects the fourth input SIN4 to the first output SOUT1 through the switch SW2b of the switching circuit CC.

[0089] The switching circuit further comprises a path referred to as second secondary path DCS1 , DCS2 for connecting the second oscillator OSC2 to the output POUT1 and the input PIN1 , respectively.

[0090] Specifically, the second secondary path DCS1 connects the second input SIN2 to the third output SOUT3 via the switch SW3b of the switching circuit CC. The second secondary path DCS2 connects the third input SIN3 to the second output POUT2 via the switch SW4b of the switching circuit CC.

[0091] The switching circuit CC also comprises a first path, called first compensation path PCC1 , PCC2 , connecting each first secondary path PCS1 , PCS2 to the oscillator OSC1 to which it is connected, so as to form a feedback loop.

[0092] In particular, the switching circuit includes a first compensation path PCC1 coupled from a node N1 arranged between the switch SW1 b of the first secondary output path PCS1 and the output SOUT4 to the oscillator OSC1 .

[0093] The switching circuit further comprises a first compensation path PCC2 coupled from a node N2 arranged between the switch SW2b of the first secondary output path PCS2 and the input SIN4 to the oscillator OSC1.

[0094] Each first compensation path PCC1, PCC2 further comprises a follower amplifier A1, A2 arranged between the nodes N1, N2, respectively, and the oscillator OSC1. Thus, when connected to each other via the first secondary paths PCS1 and PCS2, the first compensation paths PCC1, PCC2 enable compensation of the distance between the oscillator OSC1 and the resonator.

[0095] The switching circuit further comprises a path called second compensation path DCC1 , DCC2 connecting each second secondary path DCS1 , DCS2 to the oscillator OSC2 to which it is connected, so as to form a feedback loop.

[0096] In particular, the switching circuit comprises a second compensation path DCC1 coupled from a node N3 arranged between the switch SW3b of the second secondary output path DCS1 and the output SOUT3 to the oscillator OSC2.

[0097] The switching circuit further comprises a second compensation path DCC2 coupled from a node N4 arranged between the switch SW4b of the second secondary output path DCS2 and the input SIN3 to the oscillator OSC2.

[0098] Each second compensation path DCC1, DCC2 further comprises a follower amplifier A3, A4 arranged between the nodes N3, N4, respectively, and the oscillator OSC2. Thus, when connected to each other via the second secondary paths DCS1 and DCS2, the second compensation paths DCC1, DCC2 enable compensation of the distance between the oscillator OSC2 and the resonator.

[0099] In addition, the switching circuit CC is configured to be able to withstand a voltage of 5V.

[0100] The microcontroller MIC further comprises a control unit UC circuit configured to control the switches SW1a, SW1b, SW2a, SW2b, SW3a, SW3b, SW4a and SW4b of the switching circuit CC. The control unit UC may be a processor.

[0101] Specifically, the control unit UC circuit is configured as follows:

[0102] connecting the first oscillator OSC1 to the input PIN1 and the output POUT1 of the pair of input / output cells CEL1 , CEL2 by closing the switches SW2a and SW1a of the first main paths PCP2 , PCP1 , respectively;

[0103] connecting the second oscillator OSC2 to the input PIN2 and the output POUT2 of the pair of input / output cells CEL1 , CEL2 by closing the switches SW4a and SW3a of the second main paths DCP2 , DCP1 , respectively; or

[0104] connecting the first oscillator OSC1 to the input PIN2 and the output POUT2 of the pair of input / output cells CEL1 , CEL2 by closing the switches SW2b and SW1b of the first secondary paths PCS2, PCS1 respectively; or

[0105] The second oscillator OSC2 is connected to the input PIN1 and the output POUT1 of the pair of input / output cells CEL1 , CEL2 by closing the switches SW4b and SW3b of the second secondary path DCS2 , DCS1 , respectively.

[0106] Typically, the end user will choose to connect either the first resonator intended to operate with the first oscillator OSC1 or the second resonator intended to operate with the second oscillator OSC2 via the pair of input / output units CEL1 , CEL2 .

[0107] The control unit UC circuit will then be programmed to control the switches SW1a, SW1b, SW2a, SW2b, SW3a, SW3b, SW4a and SW4b of the switching circuit CC according to the inputs PIN1, PIN2 and outputs POUT1, POUT2 of the pair of input / output cells CEL1, CEL1 to which the resonator will be connected.

[0108] Thus, for example, if the user wishes to connect a low frequency resonator to the input PIN1 and output POUT1 of the pair of input / output units CEL1, CEL2, the control unit UC will be programmed to close switches SW2a and SW1a in order to connect the first low frequency oscillator OSC1 to the low frequency resonator.

[0109] Furthermore, if the user wishes to connect a low frequency resonator to the input PIN2 and output POUT2 of the pair of input / output units CEL1, CEL2, the control unit UC will be programmed to close switches SW2b and SW1b in order to connect the first low frequency oscillator OSC1 to the low frequency resonator.

[0110] Similarly, if the user wishes to connect a high frequency resonator to the input PIN2 and output POUT2 of the pair of input / output units CEL1, CEL2, the control unit UC will be programmed to close switches SW4a and SW3a in order to connect the second high frequency oscillator OSC2 to the high frequency resonator.

[0111] Furthermore, if the user wishes to connect a high frequency resonator to the input PIN1 and output POUT1 of the pair of input / output units CEL1, CEL2, the control unit UC will be programmed to close switches SW4b and SW3b in order to connect the second high frequency oscillator OSC2 to the high frequency resonator.

[0112] A bus (e.g., an n-bit bus) connects the oscillators OSC1 and OSC2 and the control unit UC. The bus carries control signals (e.g., n-bit control signals) that allow the user (using n-bit logic values) to indicate the location of the resonator to the oscillator and the control unit. Based on this information, the control unit UC controls switches SW1a, SW1b, SW2a, SW2b, SW3a, SW3b, SW4a, and SW4b to connect the resonator to the desired oscillator OSC1 or OSC2. The oscillator can also adjust its amplification of the signal generated by the resonator based on the location of the resonator. Amplifiers A1, A2, A3, and A4 are also controlled by the control signals carried by the bus.

[0113] Such a microcontroller thus allows the end user to advantageously use two external resonators using the same pair of input / output units.

[0114] exist Figures 2 to 6 Other embodiments of the microcontroller MIC are shown in FIG.

[0115] In these embodiments, the microcontroller MIC comprises two oscillators OSC1, OSC2. Oscillator OSC1 is a low-frequency oscillator and oscillator OSC2 is a high-frequency oscillator.

[0116] The microcontroller MIC further includes a plurality of input / output units CEL, including a non-shared input / output unit pair NPCEL, a first shared input / output unit pair PCEL1, and a second shared input / output unit pair PCEL2.

[0117] The microcontroller MIC further comprises a switching circuit CC connected to the two oscillators OSC1 , OSC2 , the non-shared input / output unit pair NPCEL and the two shared input / output unit pairs PCEL1 , PCEL2 .

[0118] Such a microcontroller enables greater flexibility in the choice of the design of the circuit board comprising the microcontroller and the external resonator.

[0119] Specifically, the user can select which input / output unit pair to connect the resonator to based on the desired location of the resonator on a circuit board including the microcontroller.

[0120] Specifically, if Figure 3As shown in the circuit board CE in FIG, if the end user wants to connect the low-frequency resonator RBF through the non-shared input / output unit pair NPCEL and the high-frequency resonator RHF through the shared input / output unit pair PCEL1, the control unit UC will be programmed to control the switches of the switching circuit CC so as to connect the low-frequency oscillator OSC1 to the non-shared input / output unit pair NPCEL and the high-frequency oscillator OSC2 to the shared input / output unit pair PCEL1.

[0121] In addition, if Figure 4 As shown in the circuit board CE in FIG, if the end user wants to connect the low-frequency resonator RBF through the non-shared input / output unit pair NPCEL and the high-frequency resonator RHF through the shared input / output unit pair PCEL2, the control unit UC will be programmed to control the switches of the switching circuit CC so as to connect the low-frequency oscillator OSC1 to the non-shared input / output unit pair NPCEL and the high-frequency oscillator OSC2 to the shared input / output unit pair PCEL2.

[0122] As a variation, for Figure 5 As shown in the circuit board CE in FIG, if the end user wants to connect the low-frequency resonator RBF through the shared input / output unit pair PCEL1 and the high-frequency resonator RHF through the shared input / output unit pair PCEL2, the control unit UC will be programmed to control the switches of the switching circuit CC so as to connect the low-frequency oscillator OSC1 to the input / output unit pair PCEL1 and the high-frequency oscillator OSC2 to the shared input / output unit pair PCEL2.

[0123] As a variation, for Figure 6 As shown in the circuit board CE in FIG, if the end user wants to connect the low-frequency resonator RBF through the shared input / output unit pair PCEL2 and the high-frequency resonator RHF through the shared input / output unit pair PCEL1, the control unit UC will be programmed to control the switch of the switching circuit CC so as to connect the low-frequency oscillator OSC1 to the non-shared input / output unit pair PCEL2 and the high-frequency oscillator OSC2 to the shared input / output unit pair PCEL1.

[0124] In these embodiments, those input / output units that are not used for connecting external resonators can be used for other applications.

Claims

1. A microcontroller comprising: multiple input / output unit pairs; wherein the plurality of input / output unit pairs includes at least one shared input / output unit pair; First oscillator; a second oscillator; a switching circuit coupled between the at least one shared input / output cell pair and the first oscillator and the second oscillator, wherein the switching circuit is configured to be able to connect either the first oscillator or the second oscillator to the shared input / output cell pair; wherein the shared input / output unit pair includes a first pair of pins configured to be connected to a first external resonator connected to the switching circuit, and the switching circuit connects the second oscillator to the first external resonator through the first pair of pins of the shared input / output unit pair; as well as The shared input / output unit pair includes a second pair of pins configured to be connected to a second external resonator connected to the switching circuit, and the switching circuit connects the second oscillator to the second external resonator through the second pair of pins of the shared input / output unit pair.

2. A microcontroller comprising: multiple input / output unit pairs; wherein the plurality of input / output unit pairs includes at least one shared input / output unit pair; First oscillator; a second oscillator; a switching circuit coupled between the at least one shared input / output cell pair and the first oscillator and the second oscillator, wherein the switching circuit is configured to be able to connect either the first oscillator or the second oscillator to the shared input / output cell pair; wherein the shared input / output cell pair is configured to be connectable to a first external resonator connected to the switching circuit, the switching circuit connecting the second oscillator to the shared input / output cell pair; wherein the shared input / output cell pair is configured to be connectable to a second external resonator connected to the switching circuit, the switching circuit connecting the second oscillator to the shared input / output cell pair; as well as wherein the at least one shared input / output unit pair comprises: a first unit serving as an output for the first external resonator and the second external resonator; as well as A second unit is used as an input for the first external resonator and the second external resonator.

3. The microcontroller according to claim 2 , wherein for the at least one shared input / output unit pair, the switching circuit comprises a first main path, the first main path being configured to: electrically connecting an input of the first oscillator to a first input of the second cell of the shared input / output cell pair; electrically connecting an output of the first oscillator to a first output of the first unit of the shared input / output unit pair; and Each first main path comprises a switch between the first oscillator and the first unit or the second unit to which the first main path is connected.

4. The microcontroller according to claim 3 , wherein for the at least one shared input / output unit pair, the switching circuit further comprises a second main path, the second main path being configured to: electrically connecting an input of the second oscillator to a second input of the second cell of the shared input / output cell pair; electrically connecting an output of the second oscillator to a second output of the first unit of the shared input / output unit pair; Each second main path comprises a switch between the second oscillator and the first unit or the second unit to which the second main path is connected.

5. The microcontroller according to claim 4 , wherein for the at least one shared input / output unit pair, the switching circuit further comprises a first secondary path, the first secondary path being configured to: electrically connecting the output of the first oscillator to the second output of the first cell of the shared input / output cell pair; electrically connecting the input of the first oscillator to the second input of the second cell of the shared input / output cell pair; Each first secondary path includes a switch between the first oscillator and the first unit or the second unit to which the first secondary path is connected.

6. The microcontroller according to claim 5 , wherein for the at least one shared input / output unit pair, the switching circuit further comprises a first compensation path, the first compensation path forming a feedback loop between the first oscillator and a node, the node being arranged between the switch of the first secondary path and the input / output unit to which the first secondary path is connected.

7. The microcontroller according to claim 5, wherein for the at least one shared input / output unit pair, the switching circuit further comprises a second secondary path, the second secondary path being configured to: electrically connecting the output of the second oscillator to the first output of the shared input / output cell pair; electrically connecting the input of the second oscillator to the first input of the shared input / output cell pair; and Each second secondary path includes a switch between the second oscillator and the first unit or the second unit to which the second secondary path is connected.

8. The microcontroller according to claim 7 , wherein for the at least one shared input / output unit pair, the switching circuit further comprises a second compensation path, the second compensation path forming a feedback loop between the second oscillator and a node, the node being arranged between the switch of the second secondary path and the input / output unit to which the second secondary path is connected. 9 . The microcontroller according to claim 2 , wherein the first oscillator is configured to receive an oscillation signal having a frequency of 32 kHz. 10 . The microcontroller according to claim 9 , wherein the second oscillator is configured to receive an oscillation signal having a frequency between 4 MHz and 50 MHz. The microcontroller according to claim 2 , wherein the switching circuit is configured to be able to withstand a voltage of 5V.

12. The microcontroller according to claim 2, further comprising: An external resonator circuit forms the first external resonator or the second external resonator, the first external resonator or the second external resonator being connected to the at least one shared input / output unit pair of the microcontroller.

13. A microcontroller comprising: an output unit comprising a first pin for external connection; An input unit including a second pin for external connection; First oscillator; a second oscillator; a switching circuit coupled between the first oscillator and the second oscillator and the first pin and the second pin of the input unit and the output unit; wherein the switching circuit is configured to selectively connect the first oscillator to the input unit and the output unit via the first pin and the second pin in a first switching configuration, and to selectively connect the second oscillator to the input unit and the output unit via the first pin and the second pin in a second switching configuration; The first pin of the input unit and the second pin of the output unit are configured to support connection with an external resonator.

14. A microcontroller comprising: Output unit; Input unit; First oscillator; a second oscillator; a switching circuit coupled between the first oscillator, the second oscillator, the input unit, and the output unit; wherein the switching circuit is configured to selectively connect the first oscillator to the input unit and the output unit in a first switching configuration, and to selectively connect the second oscillator to the input unit and the output unit in a second switching configuration; wherein the input unit and the output unit are configured to support connection to an external resonator; as well as The output unit includes a first output node and a second output node, and the switching circuit includes: a first switching path between the output of the first oscillator and the first output node; a second switching path between the output of the first oscillator and the second output node; and A feedback path is between the second output node and a feedback input of the first oscillator. The microcontroller of claim 14 , wherein the feedback path comprises an amplifier.

16. A microcontroller comprising: Output unit; Input unit; First oscillator; a second oscillator; a switching circuit coupled between the first oscillator, the second oscillator, the input unit, and the output unit; wherein the switching circuit is configured to selectively connect the first oscillator to the input unit and the output unit in a first switching configuration, and to selectively connect the second oscillator to the input unit and the output unit in a second switching configuration; wherein the input unit and the output unit are configured to support connection to an external resonator; as well as wherein the input unit comprises a first input node and a second input node, and wherein the switching circuit comprises: a first switching path between an input of the first oscillator and the first input node; a second switching path between the input of the first oscillator and the second input node; and A feedback path is provided between the second input node and a feedback input of the first oscillator. The microcontroller of claim 14 , wherein the feedback path comprises an amplifier.

18. A microcontroller comprising: Output unit; Input unit; First oscillator; a second oscillator; a switching circuit coupled between the first oscillator, the second oscillator, the input unit, and the output unit; wherein the switching circuit is configured to selectively connect the first oscillator to the input unit and the output unit in a first switching configuration, and to selectively connect the second oscillator to the input unit and the output unit in a second switching configuration; wherein the input unit and the output unit are configured to support connection to an external resonator; as well as The output unit includes a first output node and a second output node, and the switching circuit includes: a first switching path between the output of the second oscillator and the second output node; a second switching path between the output of the second oscillator and the first output node; and A feedback path is between the first output node and a feedback input of the second oscillator. The microcontroller of claim 18 , wherein the feedback path comprises an amplifier.

20. The microcontroller according to claim 18, wherein the input unit includes a first input node and a second input node, and wherein the switching circuit includes: a first switching path between the input of the second oscillator and the second input node; a second switching path between the input of the second oscillator and the first input node; as well as A feedback path is between the first input node and a feedback input of the second oscillator.

21. The microcontroller of claim 20, wherein the feedback path comprises an amplifier. 22 . The microcontroller according to claim 21 , wherein the first oscillator is configured to receive an oscillation signal having a frequency of 32 kHz.

23. The microcontroller according to claim 22, wherein the second oscillator is configured to receive an oscillation signal having a frequency between 4 MHz and 50 MHz.

24. The microcontroller of claim 21, wherein the switching circuit is configured to be voltage-tolerant to 5V.

25. The microcontroller according to claim 21, further comprising: An external resonator circuit forms a first external resonator or a second external resonator, the first external resonator or the second external resonator being connected to at least one shared input / output unit pair of the microcontroller.

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