lpcware

LPC11U68 USART0 auto-cts not working

Discussion created by lpcware Employee on Jun 15, 2016
Latest reply on Dec 4, 2016 by Todd Wade
Content originally posted in LPCWare by David Perry on Wed Mar 30 12:47:40 MST 2016
I'm having an issue where the UART will transmit even though CTS should be preventing it. When I look at the Modem Status Register with the debugger I see the CTS bit is 1, so it's no surprise that UART transmits. However this bit is supposed to be the complement of the input signal CTS, which is high (3.3v).

So it appears the CTS input signal is not finding its way to the register. I have the pin mux set up like so:

Chip_IOCON_PinMuxSet(LPC_IOCON, UART0_PORT, UART0_CTS_BIT, IOCON_FUNC1);

I'm using the 48 pin part and the CTS signal is connected to pin 24, PIO0_7.

I've enabled auto-cts and auto-rts like this:

Chip_UART0_SetModemControl(LPC_USART0, UART0_MCR_AUTO_RTS_EN | UART0_MCR_AUTO_CTS_EN);

Everything else is working : RX, TX and auto-rts all function as expected.

Am I missing something besides setting up the pin mux?

Thanks for any suggestions,
Dave

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