Semiconductor chip with integrated microprocessor and real-time clock

Abstract

A semiconductor chip with an integrated microprocessor (MC) and an integrated real-time clock (RTC) is described, wherein the microprocessor (MC) and the real-time clock (RTC) have independent power supplies, wherein the real-time clock (RTC) has a real-time timer (RTC) whose output is connected to a number of comparators (V1, VM), each of which is connected to an associated writable comparator register (VR1, VRM), wherein the outputs of the comparators (V1, VM) are each connected to a configurable alarm unit (AE1, AEM) configured to provide a variety of different alarm responses at their outputs, and wherein the real-time clock (RTC) has a number of start / stop counters (SSZ1, SSZK), the start and stop inputs of which are each connected to at least one of the outputs of the alarm units (AE1, AEM).

Description

A real-time clock for microcontrollers in the automotive sector is described, which takes into account the specific requirements of, for example, motor control devices.These requirements are in particular the integration of the real-time clock into the microcontroller semiconductor chip. In this case, the full functionality should be provided both when the microcontroller is switched off, microcontroller in the "sleep mode" and also during normal operation of the microcontroller.Several configurable alarms with different autonomous alarm reactions should be possible. These alarm reactions can be, for example: a) control output connection for controlling external modules, b) trigger interrupts of the microcontroller, c) wake up microcontrollers from the sleep mode.Furthermore, flexibly configurable autonomous time measurements should be possible. In addition, the date and time should be provided. Simple software development should be possible.Previously, external real-time clocks, microcontrollers with an integrated real-time clock, microcontrollers with an integrated standby controller and specially developed ASICs have been used. All these solutions have their own disadvantages and only fulfil the requirements insufficiently.External real-time clocks and microcontrollers with an integrated real-time clock that are available on the market allow only insufficiently configurable alarms or alarm reactions. In addition, triggering external components and time measurement are not possible.External real time clocks also have only one interrupt output and an external (serial) bus is needed.Microcontrollers with integrated standby controllers require an extremely complicated software development, since the standby controller is usually a stand-alone, proprietary microcontroller with a stand-alone development environment.The integration of the real-time function into a dedicated ASIC is inflexible and expensive.N XP / Freescale Semiconductor, Datasheet MC9S12XDP512RMV2 Rev. 2.21, Chandler, Arizona, 2009, shows an integrated microprocessor with an integrated capture timer.US 2008 / 0 155 289 A1 shows a microcontroller unit with an independent real-time clock. The stand-alone RTC circuit includes an RTC clock circuit that operates independently of the primary clock circuit. A power management circuit manages power for the stand-alone RTC circuit, such that the RTC clock circuit, the timer, and an I / O device operate independent of the operation mode of the processing circuit and the primary clock circuit.US 2013 / 0 080 819 A1 shows a microcontroller having a central processing unit (CPU), a plurality of peripheral devices and a programmable scheduler unit, comprising: a timer clocked by an independent clock signal; a comparator coupled to a timer register of the timer and having an output that generates an output signal; an event register coupled to the comparator; a delta-time register; and an arithmetic logic unit controlled by the output signal of the comparator.It is therefore the object of the invention to realize a simple and cost-effective real-time clock for use with microcontrollers in the automotive sector.The object is achieved by a semiconductor chip according to claim 1. Advantageous refinements of the invention are specified in the dependent claims.Accordingly, a semiconductor chip is formed with an integrated microprocessor and an integrated real-time clock, wherein the microprocessor and the real-time clock have voltage supplies which are independent of one another. The real-time clock has a real-time timer, the output of which is connected to a plurality of comparators, which are each connected to an associated writable comparison register, wherein the outputs of the comparators are each connected to a configurable alarm unit, which are configured to provide a multiplicity of different alarm reactions at their outputs. Each alarm unit has a plurality of output terminals at which predetermined alarms are displayed. The real-time clock also has a plurality of start / stop counters, the start and stop inputs of which are each connected to at least one of the outputs of the alarm units.A microcontroller is therefore integrated on a semiconductor chip together with a real-time clock, wherein both circuits are supplied with voltage independently of one another by a separate voltage supply pin. This makes it possible to operate this real-time clock independently of the rest of the microcontroller. It is possible to supply the real-time clock while the remaining ECU {Electronic Control Unit) is de-energized.The real-time clock includes a real-time timer (real time counter) and a plurality of compare registers (compare registers) for triggering alarms. These alarms are configurable and can trigger various reactions.For generating an alarm, the comparison registers are programmed with the desired comparison value. Each comparison register includes a comparator which, in an advantageous embodiment, compares it to greater, less than or equal. If the comparison is true, the alarm unit connected to the output of the comparator triggers an alarm. The alarm units are configurable and, for example, the following alarm reactions can be available:driving output terminal for triggering external devices,Set output to HIGH level,Set output to LOW level,Output levels change.Each alarm unit can act on different outputs. This makes it possible to generate complicated output changes (e.g. pulses). An alarm unit is connected to an output terminal of the semiconductor chip so that external devices can be driven. In a further development of the invention, an alarm unit can be connected to the interrupt input of the microprocessor or to a wake-up input of the microprocessor.Instead of a microprocessor, a microcontroller can also be used.Alternatively, a plurality of reactions can also be triggered simultaneously by an alarm unit.The start / stop counters are each connected to the output of a start and a stop multiplexer, at least one of the inputs of each start and each stop multiplexer being connected to one of the outputs of each alarm unit for receiving hardware triggers generated by the alarm units.The start and stop multiplexers are configurable and can be configured, for example, via external connections or via the microprocessor.For time measurement, a plurality of start / stop counters are integrated. These counters can be selectively started and stopped by hardware triggers, software triggers and input ports. The hardware triggers generate the alarm units. The connections within the real-time clock and to the input connections are advantageously effected by means of a bus. In this case, the input and the output terminals of the semiconductor chip can be combined to form input / output terminals.The type of trigger and the levels of the input terminals can be freely configured in this case. For the time measurement, a start trigger is defined or a start / stop counter is started by software. The counter begins to count. A predefined stop trigger or level of an input terminal stops the counter. The count remains stationary and can be read out by software.Both an internal and an external oscillator can serve as clock generator for the real-time clock.Date and time can be calculated from the value of the real time timer. The date and time can be calculated in an analogous manner to the calculation routines of the UNIX time.The invention is explained in more detail below with reference to an exemplary embodiment with the aid of a figure. The dio Di DiFIG. shows a block diagram of a semiconductor chip according to the invention with a real-time clock.The FIGURE shows a semiconductor chip HLC according to the invention, an integrated microprocessor MC being merely indicated. The microprocessor MC can also be designed as a microcontroller. In addition to the microprocessor MC, a real-time clock EZU is integrated on the semiconductor chip HLC in a manner according to the invention, which clock has a real-time counter RTZ which is driven by an oscillator OSC. The oscillator OSC can also be arranged outside the semiconductor chip, wherein it is also possible to arrange only the oscillator crystal outside the semiconductor chip HLC.In a manner according to the invention, the real-time clock EZU has a number M of comparisons V1... VMs, which in the example shown are connected to the real-time timer RTC by means of a bus. Each comparator V1... VM is assigned a compare register VR1 to VRM. Values can be written into these registers VR1 to VRM, the comparators V1 to VM comparing in each case whether the value of the real-time timer RTC is identical to that in the respective comparison register VR1... VRM is equal to or greater than or less than the stored value and, depending on this, emits a signal to a respective alarm unit AE1 to AEM. The comparators V1 to VM can be set in this case as to whether they compare to greater, less than or equal.The alarm units AE1 to AEM each have a plurality of output terminals at which certain alarms are displayed. The alarm units A1 to AEM can be adjusted in this case, so that the signal of the respectively assigned comparator V1 to VM either leads only to one alarm at an output of an alarm unit AE1 to AEM or else to a plurality of alarms.The figure shows as possible alarms a wake-up alarm wake-up, for example for waking the microprocessor MC from standby mode, an interrupt for interrupting a program sequence in the microprocessor MC, an output HW_trigger for actuating start-stop counters SSZ 1 to SSZK on the semiconductor chip HLC, and an output for connection to input / output connections IO port 0 to IO port N on the semiconductor chip HLC.The terminals HW_trigger for driving the counters SSZ 1 to SSTC and the terminals for driving the input / output terminals IO port 0 to IO port N are connected to a bus BUS, whereby lines can be saved. The bus BUS is likewise connected to the input / output terminals IO port 0 to IO port N of the semiconductor chip HLC.The start-stop counters are assigned SSZ 1 to SSZK respectively at least one start multiplexer STM 1 to STMK and one stop multiplexer SPM 1 to SPMK, which have a number of inputs which can be switched through to the start-stop counters SSZ 1 to SSZK by means of the multiplexers STM 1 to STMK and SPM 1 to SPMK, wherein the multiplexers STM 1 to STMK and SPM 1 to SPMK can be adjusted.In the illustrated exemplary embodiment of the figure, the start and stop multiplexers STM1 to STMK and SPM1 to SPMK each have three inputs, wherein one HW_trigger serves to connect the multiplexers STM1 to STMK and SPM1 to SPMK to the alarm units AE1 to AEM via the bus BUS. The respective second inputs connect the multiplexers STM1 to STMK and SPM1 to SPMK to the input / output terminals IO port 0 to IO port N of the semiconductor chip HLC via the bus BUS. They also have input terminals SW_Trigger which allow them to pass commands of the microprocessor MC to the start-stop counters SSZ1 to SSZK.A real-time timer, comparator and counter are advantageously combined in order to meet the requirements of a real-time clock in the automotive sector with minimal effort. In addition to the purely real-time clock function with date and time, alerting or time measurements can be performed.This functionality can be provided in energized and non-energized operation of a control unit.By combining the microprocessor or microcontroller with the real-time clock on a semiconductor chip, the programming of the clock is particularly simple and flexible. The standard development environment of the microprocessor may be used. Special knowledge is not required and changes are possible at any time.

Claims

Semiconductor chip having an integrated microprocessor (MC) and an integrated real-time clock (EZU), wherein - the microprocessor (MC) and the real-time clock (EZU) have voltage supplies which are independent of one another, - the real-time clock (EZU) has a real-time timer (RTC), the output of which is connected to a plurality of comparators (V1, VM) which are each connected to an associated writable comparison register (VR1, VRM), - the outputs of the comparators (V1, VM) are each connected to a configurable alarm unit (AE1, AEM) which are configured to provide a plurality of different alarm reactions at their outputs, each alarm unit (AE1, AEM) having a plurality of output connections in each case, The real-time clock (EZU) having a plurality of start / stop counters (SSZ1, SSZK) for time measurements, on which predetermined alarms are displayed, and the start / stop counters (SSZ1, SSZK) are each connected to the output of a start (STM1, STMK) and a stop multiplexer (SPM1, SPMK), at least one of the inputs of each start and each stop multiplexer (STM1, STMK, SPM1, SPMK) being connected to one of the outputs of each alarm unit (AE1, AEM) for receiving hardware triggers generated by the alarm units.Semiconductor chip according to Claim 1, characterized in that the comparators (V1, VM) are designed to indicate at their outputs whether the value of the real-time timer (RTC) is greater than, less than or equal to the value of the respective comparison register (VR1, VRM) connected to them.Semiconductor chip according to Claim 1 or 2, characterized in that at least one output of a respective alarm unit (AE1, AEM) is connected to an output connection (IO PORT 0, IO port N) of the semiconductor chip.Semiconductor chip according to one of Claims 1 to 3, characterized in that the connection of the start and stop inputs of the start / stop counters (SSZ1, SSZK) to in each case at least one of the outputs of the alarm units (AE1, AEM) and / or the connection of an output of a respective alarm unit (AE1, AEM) to an output connection (IO PORT 0, IO port N) of the semiconductor chip takes place via a bus (BUS).Semiconductor chip according to one of Claims 1 to 4, characterized in that at least one output of a respective alarm unit (AE1, AEM) is an interrupt output for connection to the microprocessor (MC).Semiconductor chip according to one of Claims 1 to 5, characterized in that at least one of the inputs of each start multiplexer and each stop multiplexer (STM1, STMK, SPM1, SPMK) is connected to the microprocessor (MC).Semiconductor chip according to one of Claims 1 to 6, characterized in that at least one of the inputs of each start multiplexer and each stop multiplexer (STM1, STMK, SPM1, SPMK) is connected to an output terminal (IO PORT 0, IO port N) of the semiconductor chip.Semiconductor chip according to one of Claims 1 to 5 or according to Claim 7, characterized in that the connection is a bus connection (BUS).

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