osd-contiki/tests/uart1-loopback.c
2009-04-04 15:52:09 -04:00

43 lines
1.5 KiB
C

#define GPIO_FUNC_SEL0 0x80000018 /* GPIO 15 - 0; 2 bit blocks */
#define BASE_UART1 0x80005000
#define UART1_CON 0x80005000
#define UART1_STAT 0x80005004
#define UART1_DATA 0x80005008
#define UR1CON 0x8000500c
#define UT1CON 0x80005010
#define UART1_CTS 0x80005014
#define UART1_BR 0x80005018
#include "embedded_types.h"
__attribute__ ((section ("startup")))
void main(void) {
/* Restore UART regs. to default */
/* in case there is still bootloader state leftover */
*(volatile uint32_t *)UART1_CON = 0x0000c800; /* mask interrupts, 16 bit sample --- helps explain the baud rate */
/* INC = 767; MOD = 9999 works: 115200 @ 24 MHz 16 bit sample */
#define INC 767
#define MOD 9999
*(volatile uint32_t *)UART1_BR = INC<<16 | MOD;
/* see Section 11.5.1.2 Alternate Modes */
/* you must enable the peripheral first BEFORE setting the function in GPIO_FUNC_SEL */
/* From the datasheet: "The peripheral function will control operation of the pad IF */
/* THE PERIPHERAL IS ENABLED. */
*(volatile uint32_t *)UART1_CON = 0x00000003; /* enable receive and transmit */
*(volatile uint32_t *)GPIO_FUNC_SEL0 = ( (0x01 << (14*2)) | (0x01 << (15*2)) ); /* set GPIO15-14 to UART (UART1 TX and RX)*/
uint8_t c;
while(1) {
// *(volatile uint32_t *)UART1_DATA = (uint8_t)'U';
if(*(volatile uint32_t*)UR1CON > 0) {
/* Receive buffer isn't empty */
/* read a byte and write it to the transmit buffer */
c = *(volatile uint32_t *)UART1_DATA;
*(volatile uint32_t *)UART1_DATA = c;
}
};
}