87 lines
2.1 KiB
C
87 lines
2.1 KiB
C
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#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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#define GPIO_PAD_DIR0 0x80000000
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#define GPIO_DATA0 0x80000008
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#include "embedded_types.h"
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#define reg(x) (*(volatile uint32_t *)(x))
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#define DELAY 400000
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void putc(uint8_t c);
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void puts(uint8_t *s);
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void put_hex(uint8_t x);
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void put_hex16(uint16_t x);
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void put_hex32(uint32_t x);
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const uint8_t hex[16]={'0','1','2','3','4','5','6','7',
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'8','9','a','b','c','d','e','f'};
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__attribute__ ((section ("startup")))
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void main(void) {
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uint8_t c;
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*(volatile uint32_t *)GPIO_PAD_DIR0 = 0x00000100;
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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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reg(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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reg(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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reg(UART1_CON) = 0x00000003; /* enable receive and transmit */
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reg(GPIO_FUNC_SEL0) = ( (0x01 << (14*2)) | (0x01 << (15*2)) ); /* set GPIO15-14 to UART (UART1 TX and RX)*/
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while(1) {
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};
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}
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void putc(uint8_t c) {
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while(reg(UT1CON)==31); /* wait for there to be room in the buffer */
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reg(UART1_DATA) = c;
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}
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void puts(uint8_t *s) {
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while(s && *s!=0) {
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putc(*s++);
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}
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}
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void put_hex(uint8_t x)
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{
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putc(hex[x >> 4]);
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putc(hex[x & 15]);
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}
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void put_hex16(uint16_t x)
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{
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put_hex((x >> 8) & 0xFF);
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put_hex((x) & 0xFF);
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}
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void put_hex32(uint32_t x)
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{
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put_hex((x >> 24) & 0xFF);
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put_hex((x >> 16) & 0xFF);
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put_hex((x >> 8) & 0xFF);
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put_hex((x) & 0xFF);
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}
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