LP-MSP430FR2476: Can't communicate at lower baud rate

Danilo A.

Part Number: LP-MSP430FR2476
Other Parts Discussed in Thread: MSP-FET

Hi Team,

Our customer is using LP-MSP430FR2476 evaluation module. He can communicate with the MCU through UART at 4800 and 9600 bps but when he changed the baud rate to 1200 and 2400 bps he doesn't received any data from the device. He had tried all the configurations at able 22-5 of the MSP430FRxx and MSP430FR2xx User's Guide but it still doesn't work. What could be the cause of this issue?

Regards,

Danilo

over 2 years ago

0 Keith Barkley over 2 years ago

Guru 35620 points

Has he put a scope on it?

0 Bruce McKenney47378 over 2 years ago

Guru 88700 points

The MSP430 debugger guide (SLAU647O) Table 14 suggests that the backchannel UART doesn't support <4800bps. I haven't tried it, so I'm not sure what symptom to expect.

0 Danilo A. over 2 years ago in reply to Bruce McKenney47378

TI__Mastermind 24715 points

Hi Keith and Bruce,

Thank you for your response. Here are the waveforms of the UART and codes at different baud rates.

Baud rate = 1200

Baud rate = 2400

Baud rate = 4800

Baud rate = 9600

Baud rate = 1200

Baud rate = 2400

Baud rate = 4800

Baud rate = 9600

Regards,

Danilo

0 Keith Barkley over 2 years ago in reply to Danilo A.

Guru 35620 points

If Bruce is correct, and he usually is, than the issue is with the MSP-FET not the MCU.

0 Eddie LaCost over 2 years ago in reply to Keith Barkley

TI__Mastermind 38620 points

As Bruce mentioned, the back channel UART on the launchpad board is the limitation. The device can communicate at lower speeds, but this cannot be tested with the back channel UART.

0 Danilo A. over 2 years ago in reply to Eddie LaCost

TI__Mastermind 24715 points

Hi Team,

Thank you for your response. Alternatively, our customer could disconnect the back channel UART from the MCU through J101 then connect an external USB to UART converter to MCU to be able to communicate at lower baud rate.

Thank you very much for your help.

Regards,

Danilo

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LP-MSP430FR2476: Can't communicate at lower baud rate