MSP430G2553: QFN Package TX pin appears to be wrong

Jason Reeder

Part Number: MSP430G2553

Customer states that the processor is transmitting data out signals from its RX pin instead of its TX pin.

The TX pin for this QFN package should be P1.2 (Pin 2) but the processor is talking about from the P1.1 (pin 1) pin instead.

I've confirmed the customer's understanding of pinout matches the datasheet diagram for the QFN package (below).

Any suggestions?

over 3 years ago

0 David Schultz over 3 years ago

Guru 25295 points

Since it would require a change to the die (and the die should be the same no matter which package it is in.) to disassociate the UART functions from the rest of the port I/O, it should be easy to verify which pin is associated with which port pin. In other words, twiddle P1OUT and see what happens.

0 Brandon Fisher94 over 3 years ago in reply to David Schultz

TI__Mastermind 28075 points

Hi Jason,

David's suggestion should prove everything is connected internally as it should be.

If they are really seeing traffic on pin 1.1 (RXD), then I would think they must have another processor or UART transmitter that is sending information on that pin.

What does their hardware setup look like when they are seeing this? Are they probing directly at the pin, or at related test point?

Best Regards,
Brandon Fisher

0 Bruce McKenney over 3 years ago

Guru 100965 points

This looks very similar to:

https://e2e.ti.com/support/microcontrollers/msp-low-power-microcontrollers-group/msp430/f/msp-low-power-microcontroller-forum/1104227/msp430g2553-uart-pins-incorrect-in-qfn-package

What is the test case (equipment/software)? A scope trace of the RST and TEST pins at startup would probably be useful.

**Attention** This is a public forum

MSP low-power microcontrollers

MSP low-power microcontroller forum

MSP430G2553: QFN Package TX pin appears to be wrong