Question regarding hardware serial and GPIO

[Andy Wood]

Hello,

I am receiving some serial data using HSERIN on a 16F88. I don't need to TX any data. Can I use RB5 (the UART TX pin) as GPIO or is it locked to serial TX function once the SPEN bit is set?

Regards,

Andy

[Demon]

Have you tried disabling TX function and blinking an LED on that pin?

Robert

[spcw1234]

I have never tried it with a 16F, but with 18F parts I could not make use on the other USART pin when only one was needed. I may have been setting something up wrong though. Best just give it a try.

[timmers]

When you enable SPEN it takes over both pins as you suspected.

[Andy Wood]

Thanks for the replies. The UART TX pin cannot be used fro GPIO in this case.

Andy

[languer]

From my experience, you can use the TX pin as an input. This same experienced is shared and discussed on the Microchip forum. However, I don't think you should do it if it can be avoided. Again, I have some prototypes which use it that way and they work without issues; but it seems like undocumented (likely unsupported).