LPC MicrocontrollersのトピックRe: LPC 1114/333 UART RX not working

LPC 1114/333 UART RX not working

Sac10 — Fri, 27 Oct 2023 05:48:34 GMT

Dear sir,

I am using the LPC 1114/333 IC in that external frequency(crystal oscillator) is 12Mhz. we pin muxed 11th and 12th pin as UART RX and TX. after pin muxing UART TX pin is working but RX pin is not working in both interrupt and polling method . 46th and 47th pin of controller is used for ISP programming purpose. I attached the project code,can u please give the solution for this issue.

Thanks in advance, waiting for response

Re: LPC 1114/333 UART RX not working

xiangjun_rong — Mon, 06 Nov 2023 03:23:05 GMT

Hi,

sorry for the delay.

The uart of LPC1114 can output waveform for the TXD pin, it means that the uart works fine. Regarding the uart receiver can not work, I suppose that the clock frequency of uart of LPC1114 does not match with that of the transmitter.

Pls try to use system oscillator as the uart clock source, the system oscillator clock accuracy is more accurate than that of internal IRC.

Hope it can help you

XiangJun Rong

Re: LPC 1114/333 UART RX not working

raghavendra_rcb_55 — Mon, 06 Nov 2023 06:54:06 GMT

/* Add this line after setting up uart RX pinmux */

LPC_IOCON->RXD_LOC=0x01;

/*
0x0 Selects RXD function in pin location PIO1_6/RXD/CT32B0_MAT0
0x1 Selects RXD function in pin location PIO2_7/CT32B0_MAT2/RXD
0x2 Selects RXD function in pin location PIO3_1/DSR/CT16B0_MAT1/RXD
0x3 Selects RXD function in pin location PIO3_4/CT16B0_CAP1/RXD