Power-on reset exception

Hi Jason,

According to the device family user's guide, the WDT should automatically be configured in watchdog mode with a ~32ms reset interval unless otherwise changed or halted at the beginning of the code:

This fact would lead me to believe that your MCU is not properly being reset to trigger a POR. This could be the result of a HW issue surrounding the Vcc, Vss, or RST pins. Please refer to the MSP430 Hardware Tools User's Guide to ensure that you are following the recommended HW design for using 4-wire JTAG communication (Figure 2-1).

There are a couple of issues I see already that may address your problem:

• The pullup resistor on the RST line should be 47kOhms
• The capacitor to GND on the RST line should be 10nF
• All Vss signals should be connected directly to the same MCU GND
• All Vcc signals should be connected directly to the same MCU Vcc

Best regards,

Matt

Hi  Matt,

thanks for your advice,this problem has been solved by removing the 1k ohm (vcc).

Jason,

The original circuit was not operating properly because with the addition of R6, the circuit was not following TI's recommended AVCC connection thus it was out of specification. Physically, it was probably not working properly due to an impact on the actual supply voltage level reaching the chip.

Best regards,

Matt