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