Loading circuit supporting skipping watchdog circuit

Abstract

The utility model 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 utility model relates to the technical field of medical devices, in particular to a loading circuit that supports skipping the watchdog circuit. Background Art

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

[0003] At the same time, these medical devices need to collect data continuously for 24 hours. 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 1.6 s) is preset. When the MCU stops sending signals to the watchdog chip for more than the preset time T, that is, when the "feeding the dog" operation stops 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, it is found in actual research and development tests or device use that if the MCU is firmware-updated based on the wired method of BSL / JTAG, the upgrade process is as follows: first, the existing program in the MCU is erased, and then the new firmware is written in. The time for this firmware upgrade and update 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, technicians must open the outer shell of the device, disconnect the reset wire of the watchdog circuit from the MCU, and then perform the firmware loading operation. Such an 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 Utility Model

[0005] In order to solve the problem that when the medical device in the prior art updates the firmware in a wired manner, it is necessary to manually disconnect the watchdog circuit, which reduces the work efficiency, the present utility model provides a loading circuit that supports skipping the watchdog circuit. It does not require manual disconnection of the watchdog circuit and skips the watchdog circuit during the firmware loading process, effectively reducing the complexity of the upgrade steps and improving the work efficiency.

[0006] The technical solution of the present utility model is as follows: A loading circuit that supports skipping the watchdog circuit, which includes: watchdog chip U513. It is characterized in that it further includes: analog switch chip U514, resistors R531, R532, R533, R534 and R535, capacitor C530 and firmware loading socket;

[0007] 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 grounded; 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; The WDI pin of pin 8 of the watchdog chip U513 is connected to the WDI pin of the main control chip of the medical device;

[0008] 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;

[0009] 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 main control chip of the medical device and one end of the resistor R535;

[0010] 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.

[0011] Its further features are as follows:

[0012] It further includes: resistors R525, R526 and R529, switches SW501, SW502 and SW503;

[0013] 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;

[0014] 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;

[0015] It further includes: an upgrade data insertion interface, the upgrade data insertion interface is of a model matching the firmware loading socket, and the pins corresponding to Pin 6 and Pin 9 of the firmware loading socket in the upgrade data insertion interface are shorted to each other;

[0016] The firmware loading socket supports the BSL standard and the JTAG standard;

[0017] The firmware loading socket is implemented based on a 9-terminal serial port connector;

[0018] It further includes: a capacitor C529 and a capacitor C528, 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.

[0019] The loading circuit supporting watchdog circuit skipping provided by this application sets an analog switch chip U514. The reset signal output terminal of pin 1 of the watchdog chip is first connected to pin 6 of the simulator switch U514 chip, and then sent to the RST pin of the medical device main control chip through pin 5 of the simulator switch chip U514. The medical device main control chip is connected to pin 8 of the watchdog chip through the WDI pin for dog feeding operation. In the default startup state, pins 5 and 6 of the simulator switch U514 chip are conducting. During normal operation, the reset signal sent from pin 1 of the watchdog chip can be sent to the RST pin of the medical device main control chip through pin 6 of the simulator switch U514 chip. In this application, pin 1 of the analog switch chip U514 is connected to pin 6 of the firmware loading socket, and at the same time, pin 9 of the firmware loading socket is grounded. When it is necessary to load updated firmware, pins 6 and 9 of the firmware loading socket are conducting and grounded at the same time. At this time, 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, at this time, pin 5 of the simulator switch U514 chip will be disconnected from pin 6 and conduct with pin 4. After pins 5 and 4 of the simulator switch U514 chip are conducting, the reset signal of pin 1 of the watchdog chip cannot be transmitted to the medical device main control chip, thus realizing skipping the reset signal of the watchdog chip and enabling the firmware loading process to continue. The technical solution of this application does not require opening the shell of the medical device. By conducting pins 9 and 6 in the firmware loading socket, the reset signal of the watchdog chip can be skipped, effectively reducing the complexity of the upgrade steps and improving work efficiency. Description of the Drawings

[0020] Figure 1 It is the connection circuit of the watchdog chip and the simulator switch chip in the loading circuit of this application;

[0021] Figure 2 It is the BSL loading port circuit in this application;

[0022] Figure 3 It is an example circuit of the medical device main control chip. Detailed Implementation Manner

[0023] As Figure 1 and Figure 2 shown, this application includes a loading circuit supporting watchdog circuit skipping, which includes: watchdog chip U513, analog switch chip U514, resistors R531, R532, R533, R534 and R53, capacitor C530 and firmware loading socket XS505, resistors R525, R526 and R529, and switches SW501, SW502 and SW503.

[0024] In this embodiment, the watchdog chip U513 is implemented based on the watchdog chip with the model number TPS3705DGN; the analog switch chip U514 is implemented based on the switch chip with the model number 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 arranged on the shell of the medical device, providing a wired connection data interface. Based on the firmware loading socket XS505, the corresponding data cable is used to implement wired data transmission, including operations such as firmware upgrade or device memory data reading. The firmware loading socket supports the BSL (Bootstraploader) standard and the JTAG (Joint Test Action Group) standard.

[0025] The medical device in this embodiment is a dynamic electrocardiograph recorder, and the main control chip, as Figure 3 shown, is implemented based on the MCU chip U504. The specific models include: TMS430F5438IPZ, TMS430F5436IPZ, TMS430F5419IPZ, TMS430F5438AIPZ, TMS430F5436AIPZ or TMS430F5419AIPZ, all of which are applicable to the loading circuit of this application.

[0026] 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 grounded; 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; the WDI pin of 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.

[0027] To ensure power supply stability, bypass capacitors are set 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 stability of the watchdog chip U513 is ensured through capacitor C529, and the power supply stability of the analog switch chip U514 is ensured through capacitor C528.

[0028] 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 the stability of the power signal connected to the chip.

[0029] Pin 1 of the firmware loading socket is connected to the BOOTTCK pin (pin 95) of the medical device main control chip; 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.

[0030] Pin 3 of the switch SW501 is connected to the TMS pin (pin 94) 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 (pin 93) of the medical device main control chip; pin 1 of the switch SW502 is connected to the BOOTRXD pin (pin 19) of the medical device main control chip; pin 3 of the switch SW503 is connected to the TDO pin (pin 92) of the medical device main control chip; pin 1 of the switch SW502 is connected to the BOOTTXD pin (pin 18) of the medical device main control chip.

[0031] The switches SW501, SW502, and SW503 are set between the firmware loading socket XS505 and the medical device main control chip U504 to connect 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.

[0032] Since the firmware loading socket supports the BSL standard and the JTAG standard, the specific switch connection methods in the switches SW501, SW502, and SW503 are selected according to the used standard. The pins included in the standard JTAG are: TMS, TCK, TDI, TDO; the pins included in the BSL are: TXD, RXD, RST, TCK. Figure 2When the connection method in it is used for data transmission using the BSL protocol, all three switches connect the 2-pin and the 1-pin; if the JTAG standard is used, all three switches are adjusted to connect the 2-pin and the 3-pin. Based on the switches SW501, SW502, and SW503, it is ensured that the hardware in this application can support both the BSL standard and the JTAG standard, making it more practical.

[0033] By default, the connection between pin 6 and pin 9 of the firmware loading socket XS505 is disconnected. Only when the firmware needs to be upgraded, do they need to be connected together. There are many ways to connect pin 6 and pin 9 of the specific firmware loading socket XS505 to each other, such as directly shorting through a cable or connecting through a switch. In this application, 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 is matched with the firmware loading socket model, and the pins corresponding to pin 6 and pin 9 of the firmware loading socket in the upgrade data insertion interface are shorted to each other. It is ensured that as long as the upgrade data insertion interface is inserted into the firmware loading socket, the short connection between pin 6 and pin 9 of the firmware loading socket can be achieved.

[0034] Based on Figure 1 In the shown loading circuit, the reset signal of pin 1 of the watchdog chip U513 is first connected to pin 6 of the simulator switch U514 chip. During normal operation, pin 1 of the simulator switch U514 chip is at a high level after passing through the pull-up resistor R534, and at this time, pin 5 and pin 6 of the U514 chip are conducting. During normal operation, the main control chip of the medical device connects to pin 8 of the watchdog chip through the WDI pin (pin 26) for the dog feeding operation; once the main control chip of the medical device fails and does not send a dog feeding signal to the watchdog chip for a period exceeding a predetermined time, such as 1.6 s, the reset signal sent from pin 1 of the watchdog chip is sent to the reset pin RST of the main control chip of the medical device through pin 6 of the simulator switch U514 chip, and the main control chip of the medical device is restarted and reset.

[0035] When firmware needs to be loaded, it is connected to the download through a customized connector and the firmware loading socket XS505. The 6th and 9th pins of the pins inserted into the XS505 socket are grounded simultaneously. When the pins inserted into the interface for the loaded upgrade data are docked with the socket XS505, the 6th and 9th pins of XS505 are short-circuited to GND 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 conducted; the reset signal of the 1st pin of the watchdog chip cannot be transmitted to the medical device main control chip through the 6th pin of the U514 chip, thus automatically skipping the watchdog signal and performing normal loading work. 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 conducted, and the 4th pin is connected to the 7th pin BOOTRST of the firmware loading socket XS505. The medical device main control chip receives the restart reset signal sent by the programmer during the firmware upgrade process.

[0036] After using the technical solution of the present application, a loading circuit including an analog switch chip U514 is set up. By using the external socket originally available on the medical device: the firmware loading socket XS505, the 6th and 9th pins of the firmware loading socket XS505 are connected to the analog switch. By using the characteristics of the analog switch, the internal switch change of 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 realize sending the reset signal sent by the watchdog chip to the medical device main control chip, or disconnecting the sending of the watchdog reset signal to the medical device main control chip. When firmware needs to be loaded, only a customized data cable is needed to realize the occurrence of disconnecting the watchdog reset signal, without the need to disassemble the shell of the medical device, greatly reducing the operation complexity and improving the efficiency. Moreover, the cost of this solution is extremely low and is very suitable for use in various low-cost medical devices.

Claims

1. A loading circuit that supports skipping the watchdog circuit, comprising: Watchdog chip U513, characterized in that it further includes: analog switch chip U514, resistors R531, R532, R533, R534 and R535, capacitor C530 and 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 grounded; pin 6 of the watchdog chip U513 is connected to the other end of the resistor 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; the WDI pin of pin 8 of the watchdog chip U513 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 main control chip of the medical device 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. The loading circuit supporting skipping the watchdog circuit according to claim 1, wherein: It further 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.

3. The loading circuit for supporting skipping the watchdog circuit according to claim 1, wherein: It further includes: an upgrade data insertion interface, the upgrade data insertion interface being of a model matching that of the firmware loading socket, and the pins corresponding to the 6th and 9th pins of the firmware loading socket in the upgrade data insertion interface being shorted to each other.

4. The loading circuit for supporting skipping the watchdog circuit according to claim 1, wherein: The firmware loading socket supports the BSL standard and the JTAG standard.

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

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

Images