topic Re: Can I route a pin to PINT and USART at the same time? in LPC Microcontrollers

Can I route a pin to PINT and USART at the same time?

wangyanjun — Mon, 18 Jan 2021 04:36:50 GMT

My application need to capture the USART's RxD falling edge. Can I route the pin (P0_29) to PINT and USART at the same time?

Thank you!

Re: Can I route a pin to PINT and USART at the same time?

ZhangJennie — Mon, 18 Jan 2021 05:37:11 GMT

Please let me know your chip full part number. I will check.

Thanks,

Jun Zhang

Re: Can I route a pin to PINT and USART at the same time?

wangyanjun — Mon, 18 Jan 2021 06:51:56 GMT

LPC54616J512BD100

Re: Can I route a pin to PINT and USART at the same time?

ZhangJennie — Mon, 18 Jan 2021 08:31:17 GMT

No, you can't config the pin as PINT and USART at the same time.

Re: Can I route a pin to PINT and USART at the same time?

wangyanjun — Tue, 19 Jan 2021 04:51:29 GMT

I just test it.

I config P0_29 as USART RxD and PINT int0 input at the same time. When there is signal on the RxD pin, it can generate PINT interrupt and USART receive interrupt.

Re: Can I route a pin to PINT and USART at the same time?

ZhangJennie — Tue, 19 Jan 2021 08:45:17 GMT

you may get it work during debug. But we can't guarantee both of PINT and UART still work well in run mode or increase the communication speed. This usage is not suggested.

Re: Can I route a pin to PINT and USART at the same time?

wangyanjun — Tue, 19 Jan 2021 12:08:23 GMT

In run mode, it will not work?

I use PINT to capture UART start bit's falling edge only and the baudrate is 19200. Is this OK?

Thank you!

Re: Can I route a pin to PINT and USART at the same time?

ZhangJennie — Wed, 20 Jan 2021 01:21:42 GMT

Because we don't suggest user use one pin as PINT and UART at the same time. You are not using part with our suggested way, so by checking, we can't guarantee it.

Don't have have another pin to get PINT interrupt?

Re: Can I route a pin to PINT and USART at the same time?

wangyanjun — Wed, 20 Jan 2021 07:00:24 GMT

For new design, I can use another pin as PINT. For existing product, I want to add new function by firmware update only.

Re: Can I route a pin to PINT and USART at the same time?

ZhangJennie — Wed, 20 Jan 2021 08:22:42 GMT

As I said this is not our recommended way of using part.

We can't guarantee the function work all well if you insist working this way.