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MSP430F5438A-EP: Different software behavior with JTAG vs without JTAG

Part Number: MSP430F5438A-EP

Hi,

Our team has designed a PCB board based on MSP430F438A. For using CAN bus we are using Microchip MCP2515 along with TI CAN transceiver. 

We are using MSP-TS430PZ5X100 to verify our software before flashing on the actual PCB. We are using JTAG to flash the code.

We are interfacing Komodo CAN analyser to the MCP2515 CAN to check the CAN interface.

There are four different scenarios that we test:

1. CAN bus behavior when new software is flashed through JTAG.

2. CAN bus behavior after external power reset with JTAG still connected.

3. CAN bus behavior after removing the JTAG following the code flash without external power reset.

4. CAN bus behavior after removing the JTAG following code flash and external power reset.

With the MSP-TS430PZ5X100 connected to MCP2515 (along with TI can transceiver) all the four scenarios work. However, on our PCB the fourth scenario doesn't work. It gives CAN bus error.

We are hoping to debug it but we would need the support to know the starting point.

Thanks and Regards,

Ankit

  • Hello Ankit,

    Does your JTAG circuitry match what's recommended in Section 2.1 Signal Connections for In-System Programming and Debugging in the MSP430 Hardware Tools User's Guide? Also, are you using 4-wire JTAG or SBW? Is this consistent across both boards or is one 4-wire while the other board is SBW?

    Be mindful of the length of your JTAG traces which can negatively affect the communication speed if too long. The 14-conductor cable that connects the FET interface module and the target socket module must not exceed 8 inches (20 centimeters) in length. 

    Regards,

    James

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