Loading circuit supporting watchdog circuit skipping

Abstract

The invention provides a loading circuit supporting skipping of a watchdog circuit, which is provided with an analog switch chip U514, and a pin 1 reset signal sending end of the watchdog chip is firstly connected to a pin 6 of a simulator switch U514 chip, and then is sent to an RST pin of a medical equipment main control chip through a pin 5 of the simulator switch chip U514; when firmware needs to be loaded and updated, a pin 6 and a pin 9 of the firmware loading socket are conducted and grounded at the same time, at the moment, the potential of a pin 1 of the analog switch chip U514 is also lowered, and on the basis of the inherent characteristics of the analog switch U514, a pin 5 of the analog switch U514 chip is disconnected with the pin 6 and conducted with a pin 4; in the embodiment of the invention, the reset signal of the pin 1 of the watchdog chip cannot be transmitted to the main control chip of the medical equipment, so that the reset signal of the watchdog chip is skipped, and the firmware loading process can be kept.

Description

Technical Field

[0001] The invention relates to the technical field of medical devices, in particular to a loading circuit supporting skipping of a watchdog circuit. Background Art

[0002] In some medical devices, such as the patent with application number CN202120241531.5, a circuit for reading and writing SD card data through a USB data acquisition interface is disclosed. This circuit is mainly used in some low-priced dynamic ECG recorders or blood pressure recorders that do not support Bluetooth modules and 4G / 5G wireless network modules. These low-priced dynamic ECG recorders or blood pressure recorders record the collected ECG or blood pressure data on the SD card first. Before data analysis, the user takes out the SD card and inserts it into the card reader, and then reads the data in the SD card through the host computer software. Because wireless data transmission is not supported, in the development and actual use of these medical devices, the firmware update of the device is carried out through the serial communication protocol of BSL (Bootstraploader) or the wired method based on the JTAG interface (Joint Test Action Group) for firmware data transmission.

[0003] At the same time, these medical devices need to collect data 24 hours a day. In order to ensure the reliable operation of the device control chip MCU, a hardware watchdog circuit is generally added to the circuit. After adding the watchdog circuit, a reset waiting time T (such as 1.6s) is preset. When the MCU stops sending signals to the watchdog chip for more than the preset time T, that is, the "dog feeding" operation is stopped for more than time T, the watchdog circuit will send a reset signal to the MCU chip to restart and reset the MCU to ensure that the device will not be in a dead state for a long time.

[0004] However, in actual R&D testing or equipment use, it is found that if the MCU is upgraded via BSL / JTAG wired method, the upgrade process is: first erase the existing program in the MCU, and then write the new firmware in. The time of this firmware upgrade process usually exceeds the reset waiting time T of the watchdog. In order to ensure that the firmware upgrade process is not interrupted by the reset signal of the watchdog, the technician must open the outer shell of the device, disconnect the reset line of the watchdog circuit from the MCU, and then perform the firmware loading operation. This operation process not only increases the complexity of the firmware upgrade operation, but also greatly reduces the work efficiency, which is very unfavorable for batch firmware updates. Summary of the invention

[0005] In order to solve the problem in the prior art that when medical devices perform firmware updates based on a wired method, it is necessary to manually disconnect the watchdog circuit, which reduces work efficiency. The present invention provides a loading circuit that supports skipping the watchdog circuit. The watchdog circuit does not need to be manually disconnected, and the firmware loading process is skipped, which effectively reduces the complexity of the upgrade steps and improves work efficiency.

[0006] The technical solution of the present invention is as follows: a loading circuit supporting skipping of a watchdog circuit, comprising: a watchdog chip U513, characterized in that it also comprises: an analog switch chip U514, resistors R531, R532, R533, R534 and R535, a capacitor C530 and a firmware loading socket; Pin 1 of the watchdog chip U513 is connected to pin 6 of the analog switch chip U514; pin 2 of the watchdog chip U513 is connected to pin 3 of the watchdog chip U513; pin 4 of the watchdog chip U513 is connected to the power supply VCC; pin 5 of the watchdog chip U513 is connected to one end of the resistor R533 and then to ground; pin 6 of the watchdog chip U513 is connected to the other end of the terminal R533, one end of the resistor R531 and one end of the capacitor C530; pin 7 of the watchdog chip U513 is connected to one end of the resistor R532; pin 8 of the watchdog chip U513, the WDI pin, is connected to the WDI pin of the main control chip of the medical device; The other end of the resistor R532 is connected to the power supply VCC; the other end of the resistor R531 is connected to the power supply VCC; the other end of the capacitor C530 is grounded; Pin 1 of the analog switch chip U514 is connected to one end of the resistor R534 and pin 6 of the firmware loading socket; pin 9 of the firmware loading socket is grounded; pin 2 of the analog switch chip U514 is connected to the power supply VCC; pin 3 of the analog switch chip U514 is grounded; pin 4 of the analog switch chip U514 is connected to pin 7 of the firmware loading socket; pin 5 of the analog switch chip U514 is connected to the RST pin of the medical device main control chip and one end of the resistor R535; The other end of the resistor R534 is connected to the power supply VCC; the other end of the resistor R535 is connected to the power supply VCC.

[0007] It is further characterized by: It also includes: resistors R525, R526 and R529, switches SW501, SW502 and SW503; Pin 1 of the firmware loading socket is connected to the BOOTTCK pin of the main control chip of the medical device; Pin 2 of the firmware loading socket is connected to Pin 2 of the switch SW503; Pin 3 of the firmware loading socket is connected to Pin 2 of the switch SW502; Pin 4 of the firmware loading socket is connected to Pin 2 of the switch SW501; Pin 5 of the firmware loading socket is connected to one end of the resistor R525; the other end of the resistor R525 is grounded; Pin 8 of the firmware loading socket is connected to one end of the resistor R526; the other end of the resistor R526 is connected to one end of the resistor R529; Pin 3 of the switch SW501 is connected to the TMS pin of the main control chip of the medical device; Pin 2 of the switch SW501 is connected to the other end of the resistor R529; Pin 3 of the switch SW502 is connected to the TDI pin of the main control chip of the medical device; Pin 1 of the switch SW502 is connected to the BOOTRXD pin of the main control chip of the medical device; Pin 3 of the switch SW503 is connected to the TDO pin of the main control chip of the medical device; Pin 1 of the switch SW502 is connected to the BOOTTXD pin of the main control chip of the medical device; It also includes: an upgrade data insertion interface, the upgrade data insertion interface matches the firmware loading socket model, and the pins of the upgrade data insertion interface corresponding to the 6th and 9th pins of the firmware loading socket are short-circuited with each other; The firmware loading socket supports the BSL standard and the JTAG standard; The firmware loading socket is implemented based on a 9-terminal serial port connector; It also includes: a capacitor C529 and a capacitor C528, wherein one end of the capacitor C529 is connected to the power supply VCC, and the other end is grounded; one end of the capacitor C528 is connected to the power supply VCC, and the other end is grounded.

[0008] The present application provides a loading circuit that supports skipping a watchdog circuit, which sets an analog switch chip U514, and first connects the reset signal sending end of the watchdog chip's pin 1 to the pin 6 of the simulator switch U514 chip, and then sends it to the RST pin of the medical device main control chip through the pin 5 of the simulator switch chip U514; the medical device main control chip is connected to the pin 8 of the watchdog chip through the WDI pin to feed the dog, and in the default starting state, the pins 5 and 6 of the simulator switch U514 chip are turned on; during normal operation, the reset signal sent by the pin 1 of the watchdog chip can be sent to the RST pin of the medical device main control chip through the pin 6 of the simulator switch U514 chip; the present application Please connect pin 1 of the analog switch chip U514 to pin 6 of the firmware loading socket, and pin 9 of the firmware loading socket to ground; when it is necessary to load and update the firmware, connect pins 6 and 9 of the firmware loading socket to ground at the same time, and the potential of pin 1 of the analog switch chip U514 is also pulled down. Based on the inherent characteristics of the analog switch U514, pin 5 of the simulator switch U514 chip will be disconnected from pin 6 and connected to pin 4; after pins 5 and 4 of the simulator switch U514 chip are connected, the reset signal of pin 1 of the watchdog chip will not be transmitted to the main control chip of the medical device, thereby skipping the reset signal of the watchdog chip and maintaining the firmware loading process. The technical solution of this application does not require opening the outer shell of the medical device. By connecting pins 9 and 6 in the firmware loading socket, the reset limit of the watchdog chip can be skipped, which effectively reduces the complexity of the upgrade steps and improves work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 A connection circuit for the watchdog chip and the simulator switch chip in the loading circuit of this application; Figure 2 It is the BSL loading port circuit in this application; Figure 3 This is an example of the main control chip circuit of medical equipment. DETAILED DESCRIPTION

[0010] like Figure 1 and Figure 2 As shown, the present application includes a loading circuit that supports skipping the watchdog circuit, which includes: a watchdog chip U513, an analog switch chip U514, resistors R531, R532, R533, R534 and R535, a capacitor C530 and a firmware loading socket XS505, resistors R525, R526 and R529, and switches SW501, SW502 and SW503.

[0011] In this embodiment, the watchdog chip U513 is implemented based on the watchdog chip model TPS3705DGN; the analog switch chip U514 is implemented based on the switch chip model MAX4561. In this embodiment, the firmware loading socket XS505 is implemented based on the IDC8 terminal connector of MiniUSB. The firmware loading socket XS505 is set on the shell of the medical device, providing a wired data interface. Based on the firmware loading socket XS505, the corresponding data line is used to realize wired data transmission, including: firmware upgrade or device memory data reading and other operations. The firmware loading socket supports the BSL (Bootstraploader) standard and the JTAG (Joint Test Action Group) standard.

[0012] The medical device in this embodiment is a dynamic electrocardiograph, and the main control chip is as follows: Figure 3 As shown, it is implemented based on MCU chip U504. Specific models include: TMS430F5438IPZ, TMS430F5436IPZ, TMS430F5419IPZ, TMS430F5438AIPZ, TMS430F5436AIPZ or TMS430F5419AIPZ, all of which are suitable for the loading circuit of this application.

[0013] Pin 1 of the watchdog chip U513 is connected to pin 6 of the analog switch chip U514; Pin 2 of the watchdog chip U513 is connected to pin 3 of the watchdog chip U513; Pin 4 of the watchdog chip U513 is connected to the power supply VCC; Pin 5 of the watchdog chip U513 is connected to one end of the resistor R533 and then to ground; Pin 6 of the watchdog chip U513 is connected to the other end of the terminal R533, one end of the resistor R531 and one end of the capacitor C530; Pin 7 of the watchdog chip U513 is connected to one end of the resistor R532; Pin 8 of the watchdog chip U513 is connected to the WDI pin (pin 26) of the main control chip of the medical device. The other end of the resistor R532 is connected to the power supply VCC; the other end of the resistor R531 is connected to the power supply VCC; the other end of the capacitor C530 is grounded.

[0014] In order to ensure the stability of the power supply, bypass capacitors are provided in this application: capacitor C529 and capacitor C528. One end of capacitor C529 is connected to the power supply VCC and the other end is grounded; one end of capacitor C528 is connected to the power supply VCC and the other end is grounded. The power supply of the watchdog chip U513 is ensured to be stable through capacitor C529, and the power supply of the analog switch chip U514 is ensured to be stable through capacitor C528.

[0015] Pin 1 of the analog switch chip U514 is connected to one end of the resistor R534 and pin 6 of the firmware loading socket; pin 9 of the firmware loading socket is grounded; pin 2 of the analog switch chip U514 is connected to the power supply VCC; pin 3 of the analog switch chip U514 is grounded; pin 4 of the analog switch chip U514 is connected to pin 7 of the firmware loading socket; pin 5 of the analog switch chip U514 is connected to the RST pin (pin 96) of the medical device main control chip and one end of the resistor R535. The other end of the resistor R534 is connected to the power supply VCC; the other end of the resistor R535 is connected to the power supply VCC to ensure that the power supply signal connected to the chip is stable.

[0016] Pin 1 of the firmware loading socket is connected to the BOOTTCK pin (pin 95) of the main control chip of the medical device; pin 2 of the firmware loading socket is connected to pin 2 of the switch SW503; pin 3 of the firmware loading socket is connected to pin 2 of the switch SW502; pin 4 of the firmware loading socket is connected to pin 2 of the switch SW501; pin 5 of the firmware loading socket is connected to one end of the resistor R525; the other end of the resistor R525 is grounded; pin 8 of the firmware loading socket is connected to one end of the resistor R526; the other end of the resistor R526 is connected to one end of the resistor R529.

[0017] Pin 3 of switch SW501 is connected to the TMS pin (pin 94) of the main control chip of the medical device; pin 2 of switch SW501 is connected to the other end of resistor R529; pin 3 of switch SW502 is connected to the TDI pin (pin 93) of the main control chip of the medical device; pin 1 of switch SW502 is connected to the BOOTRXD pin (pin 19) of the main control chip of the medical device; pin 3 of switch SW503 is connected to the TDO pin (pin 92) of the main control chip of the medical device; pin 1 of switch SW502 is connected to the BOOTTXD pin (pin 18) of the main control chip of the medical device.

[0018] Switches SW501, SW502 and SW503 are set between the firmware loading socket XS505 and the medical device main control chip U504, connecting the pins of the firmware loading socket XS505 and the pins on the medical device main control chip U504 to ensure that data can be transmitted between the two.

[0019] Because the firmware loading socket supports the BSL standard and the JTAG standard, the specific switch connection mode of switches SW501, SW502 and SW503 is selected according to the standard used. The pins included in the standard JTAG are: TMS, TCK, TDI, TDO; the pins included in the BSL are: TXD, RXD, RST, TCK. Figure 2The connection method in the example is that when the BSL protocol is used for data transmission, the three switches are connected between pin 2 and pin 1; if the JTAG standard is used, the three switches are adjusted to connect between pin 2 and pin 3. Based on switches SW501, SW502, and SW503, it is ensured that the hardware in this application can support both the BSL standard and the JTAG standard, which is more practical.

[0020] By default, pins 6 and 9 of the firmware loading socket XS505 are disconnected. The two need to be connected together only when the firmware needs to be upgraded. There are many ways to connect pins 6 and 9 of the specific firmware loading socket XS505, such as short-circuiting directly through a flat cable, or connecting through a switch. In order to ensure that the signal of the watchdog chip can be skipped more conveniently, a customized data cable is used in this application, and the data socket of the customized data cable is modified to obtain an upgrade data insertion interface. The upgrade data insertion interface matches the model of the firmware loading socket, and the pins corresponding to pins 6 and 9 of the firmware loading socket in the upgrade data insertion interface are short-circuited with each other. Ensure that as long as the upgrade data insertion interface is inserted into the firmware loading socket, the short-circuiting of pins 6 and 9 of the firmware loading socket can be achieved.

[0021] based on Figure 1 In the loading circuit shown, the reset signal of the 1st pin of the watchdog chip U513 is first connected to the 6th pin of the simulator switch U514 chip. During normal operation, the 1st pin of the simulator switch U514 chip is at a high level after being pulled up by the resistor R534, and the 5th and 6th pins of the U514 chip are connected. During normal operation, the main control chip of the medical device is connected to the 8th pin of the watchdog chip through the WDI pin (26th pin) to feed the dog; once the main control chip of the medical device fails, and the predetermined time, such as 1.6s, is exceeded, and no feeding signal is sent to the watchdog chip, the reset signal sent from the 1st pin of the watchdog chip is sent to the reset pin RST pin of the main control chip of the medical device through the 6th pin of the simulator switch U514 chip, and the main control chip of the medical device is restarted and reset.

[0022] When it is necessary to load the firmware, the firmware loading socket XS505 is connected to the download through a customized connector, and the 6th and 9th pins that are plugged into the XS505 socket are grounded at the same time. When the loaded upgrade data is inserted into the pins in the interface and connected to the socket XS505, the 6th and 9th pins of XS505 are short-circuited and pulled low, then the 1st pin of the analog switch chip U514 connected to the 6th pin of XS505 is also pulled low. At this time, based on the characteristics of the analog switch, the 5th and 6th pins of the U514 chip will be automatically disconnected, and the 5th and 4th pins of the U514 chip will be connected; the reset signal of the 1st pin of the watchdog chip will not be transmitted to the main control chip of the medical device through the 6th pin of the U514 chip, thereby automatically skipping the watchdog signal and performing normal loading. At the same time, after the 5th and 6th pins of the U514 chip are disconnected, the 5th and 4th pins of the U514 chip are connected, and the 4th pin is connected to the 7th pin BOOTRST of the firmware loading socket XS505. The main control chip of the medical device receives the restart reset signal sent by the programmer during the firmware upgrade process.

[0023] After using the technical solution of the present application, a loading circuit including an analog switch chip U514 is set up, and the external socket existing on the medical device: the firmware loading socket XS505 is used to establish a connection between the 6th and 9th pins of the firmware loading socket XS505 and the analog switch. By using the characteristics of the analog switch, the switch change inside the analog switch chip U514 is controlled by disconnecting and connecting the 6th and 9th pins of the firmware loading socket XS505, so as to send the reset signal sent by the watchdog chip to the main control chip of the medical device, or disconnect the watchdog reset signal from being sent to the main control chip of the medical device. When the firmware needs to be loaded, the watchdog reset signal can be disconnected through a customized data line, without disassembling the outer shell of the medical device, which greatly reduces the complexity of the operation and improves the efficiency. Moreover, the cost of this solution is also extremely low, and it is very suitable for use in various low-cost medical devices.

Claims

1. A loading circuit for supporting skipping a watchdog circuit, comprising: The watchdog chip U513 is characterized in that it also includes: an analog switch chip U514, resistors R531, R532, R533, R534 and R535, a capacitor C530 and a firmware loading socket; Pin 1 of the watchdog chip U513 is connected to pin 6 of the analog switch chip U514; pin 2 of the watchdog chip U513 is connected to pin 3 of the watchdog chip U513; pin 4 of the watchdog chip U513 is connected to the power supply VCC; pin 5 of the watchdog chip U513 is connected to one end of the resistor R533 and then to ground; pin 6 of the watchdog chip U513 is connected to the other end of the terminal R533, one end of the resistor R531 and one end of the capacitor C530; pin 7 of the watchdog chip U513 is connected to one end of the resistor R532; pin 8 of the watchdog chip U513, the WDI pin, is connected to the WDI pin of the main control chip of the medical device; The other end of the resistor R532 is connected to the power supply VCC; the other end of the resistor R531 is connected to the power supply VCC; the other end of the capacitor C530 is grounded; Pin 1 of the analog switch chip U514 is connected to one end of the resistor R534 and pin 6 of the firmware loading socket; pin 9 of the firmware loading socket is grounded; pin 2 of the analog switch chip U514 is connected to the power supply VCC; pin 3 of the analog switch chip U514 is grounded; pin 4 of the analog switch chip U514 is connected to pin 7 of the firmware loading socket; pin 5 of the analog switch chip U514 is connected to the RST pin of the medical device main control chip and one end of the resistor R535; The other end of the resistor R534 is connected to the power supply VCC; the other end of the resistor R535 is connected to the power supply VCC.

2. A loading circuit for supporting skipping of a watchdog circuit according to claim 1, characterized in that: It also includes: resistors R525, R526 and R529, switches SW501, SW502 and SW503; Pin 1 of the firmware loading socket is connected to the BOOTTCK pin of the main control chip of the medical device; Pin 2 of the firmware loading socket is connected to Pin 2 of the switch SW503; Pin 3 of the firmware loading socket is connected to Pin 2 of the switch SW502; Pin 4 of the firmware loading socket is connected to Pin 2 of the switch SW501; Pin 5 of the firmware loading socket is connected to one end of the resistor R525; the other end of the resistor R525 is grounded; Pin 8 of the firmware loading socket is connected to one end of the resistor R526; the other end of the resistor R526 is connected to one end of the resistor R529; Pin 3 of the switch SW501 is connected to the TMS pin of the medical device main control chip; pin 2 of the switch SW501 is connected to the other end of the resistor R529; pin 3 of the switch SW502 is connected to the TDI pin of the medical device main control chip; pin 1 of the switch SW502 is connected to the BOOTRXD pin of the medical device main control chip; pin 3 of the switch SW503 is connected to the TDO pin of the medical device main control chip; and pin 1 of the switch SW502 is connected to the BOOTTXD pin of the medical device main control chip.

3. A loading circuit for supporting skipping of a watchdog circuit according to claim 1, characterized in that: It also includes: an upgrade data insertion interface, the upgrade data insertion interface matches the firmware loading socket model, and the pins of the upgrade data insertion interface corresponding to the 6th and 9th pins of the firmware loading socket are short-circuited with each other.

4. A loading circuit for supporting skipping of a watchdog circuit according to claim 1, characterized in that: The firmware loading socket supports the BSL standard and the JTAG standard.

5. The loading circuit supporting skipping of the watchdog circuit according to claim 1, characterized in that: The firmware loading socket is implemented based on a 9-terminal serial port connector.

6. The loading circuit for supporting skipping of a watchdog circuit according to claim 1, characterized in that: It also includes: a capacitor C529 and a capacitor C528, wherein one end of the capacitor C529 is connected to the power supply VCC, and the other end is grounded; one end of the capacitor C528 is connected to the power supply VCC, and the other end is grounded.

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