lpcopen with lpc1114 and UART

Discussion created by lpcware Employee on Jun 15, 2016
Latest reply on Jun 15, 2016 by lpcware
Content originally posted in LPCWare by kingsob on Fri Apr 11 13:54:21 MST 2014
I am using the nxp_lpcxpresso_11c24_periph_uart example code as a reference.

I basically created a blank lpcopen project in lpcxpresso, using the lpc_chip_11cxx_lib, and no board lib.

I then copied the source from the uart example, and changed the 2 lines for the Init_UART_PinMux.


Below is the entire code.

Everything complies fine, and I can run the example... but the problem is that the output I read in coolterm is scrambled. I have checked my terminal's settings, and verified many times its configured the same as the example code (baud rate 115200, stop bits 1, data bits 8, and no parity). The output I am seeing looks as if there is an issue with the baud rate (its similar to what you would see if you selected the wrong baud rate in your terminal).

I am using a lpc1114fn28, with no external crystal.. its just a lpc1114fn28 on a breadboard with a debugger and a uart connected.

Any ideas would be greatly appreciated.

* @brief UART interrupt example with ring buffers
* @note
* Copyright(C) NXP Semiconductors, 2012
* All rights reserved.
* @par
* Software that is described herein is for illustrative purposes only
* which provides customers with programming information regarding the
* LPC products.  This software is supplied "AS IS" without any warranties of
* any kind, and NXP Semiconductors and its licensor disclaim any and
* all warranties, express or implied, including all implied warranties of
* merchantability, fitness for a particular purpose and non-infringement of
* intellectual property rights.  NXP Semiconductors assumes no responsibility
* or liability for the use of the software, conveys no license or rights under any
* patent, copyright, mask work right, or any other intellectual property rights in
* or to any products. NXP Semiconductors reserves the right to make changes
* in the software without notification. NXP Semiconductors also makes no
* representation or warranty that such application will be suitable for the
* specified use without further testing or modification.
* @par
* Permission to use, copy, modify, and distribute this software and its
* documentation is hereby granted, under NXP Semiconductors' and its
* licensor's relevant copyrights in the software, without fee, provided that it
* is used in conjunction with NXP Semiconductors microcontrollers.  This
* copyright, permission, and disclaimer notice must appear in all copies of
* this code.

#include "chip.h"
//#include "board.h"
#include "string.h"

* Private types/enumerations/variables

/* Transmit and receive ring buffers */
STATIC RINGBUFF_T txring, rxring;

/* Transmit and receive ring buffer sizes */
#define UART_SRB_SIZE 128/* Send */
#define UART_RRB_SIZE 32/* Receive */

/* Transmit and receive buffers */
static uint8_t rxbuff[UART_RRB_SIZE], txbuff[UART_SRB_SIZE];

const char inst1[] = "LPC11xx UART example using ring buffers\r\n";
const char inst2[] = "Press a key to echo it back or ESC to quit\r\n";

* Public types/enumerations/variables

* Private functions

static void Init_UART_PinMux(void)

* Public functions

* @briefUART interrupt handler using ring buffers
* @returnNothing
void UART_IRQHandler(void)
/* Want to handle any errors? Do it here. */

/* Use default ring buffer handler. Override this with your own
   code if you need more capability. */
Chip_UART_IRQRBHandler(LPC_USART, &rxring, &txring);

const uint32_t OscRateIn = 0;
const uint32_t ExtRateIn = 0;

* @briefMain UART program body
* @returnAlways returns 1
int main(void)
uint8_t key;
int bytes;


/* Setup UART for 115.2K8N1 */
Chip_UART_SetBaud(LPC_USART, 115200);

/* Before using the ring buffers, initialize them using the ring
   buffer init function */
RingBuffer_Init(&rxring, rxbuff, 1, UART_RRB_SIZE);
RingBuffer_Init(&txring, txbuff, 1, UART_SRB_SIZE);

/* Enable receive data and line status interrupt */

/* preemption = 1, sub-priority = 1 */
NVIC_SetPriority(UART0_IRQn, 1);

/* Send initial messages */
Chip_UART_SendRB(LPC_USART, &txring, inst1, sizeof(inst1) - 1);
Chip_UART_SendRB(LPC_USART, &txring, inst2, sizeof(inst2) - 1);

/* Poll the receive ring buffer for the ESC (ASCII 27) key */
key = 0;
while (key != 27) {
bytes = Chip_UART_ReadRB(LPC_USART, &rxring, &key, 1);
if (bytes > 0) {
/* Wrap value back around */
if (Chip_UART_SendRB(LPC_USART, &txring, (const uint8_t *) &key, 1) != 1) {

/* DeInitialize UART0 peripheral */

return 1;