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- /*
- uart.c: UART access routines
- */
- #include <arm/NXP/LPC17xx/LPC17xx.h>
- #include "bits.h"
- #include "config.h"
- #include "uart.h"
- #include "led.h"
- /* A few symbols to make this code work for all four UARTs */
- #if defined(CONFIG_UART_NUM) && CONFIG_UART_NUM == 0
- # define UART_PCONBIT 3
- # define UART_PCLKREG PCLKSEL0
- # define UART_PCLKBIT 6
- # define UART_REGS LPC_UART0
- # define UART_HANDLER UART0_IRQHandler
- # define UART_IRQ UART0_IRQn
- #elif CONFIG_UART_NUM == 1
- # define UART_PCONBIT 4
- # define UART_PCLKREG PCLKSEL0
- # define UART_PCLKBIT 8
- # define UART_REGS LPC_UART1
- # define UART_HANDLER UART1_IRQHandler
- # define UART_IRQ UART1_IRQn
- #elif CONFIG_UART_NUM == 2
- # define UART_PCONBIT 24
- # define UART_PCLKREG PCLKSEL1
- # define UART_PCLKBIT 16
- # define UART_REGS LPC_UART2
- # define UART_HANDLER UART2_IRQHandler
- # define UART_IRQ UART2_IRQn
- #elif CONFIG_UART_NUM == 3
- # define UART_PCONBIT 25
- # define UART_PCLKREG PCLKSEL1
- # define UART_PCLKBIT 18
- # define UART_REGS LPC_UART3
- # define UART_HANDLER UART3_IRQHandler
- # define UART_IRQ UART3_IRQn
- #else
- # error CONFIG_UART_NUM is not set or has an invalid value!
- #endif
- static uint8_t uart_lookupratio(float f_fr) {
- uint16_t errors[72]={0,67,71,77,83,91,100,111,125,
- 133,143,154,167,182,200,214,222,231,
- 250,267,273,286,300,308,333,357,364,
- 375,385,400,417,429,444,455,462,467,
- 500,533,538,545,556,571,583,600,615,
- 625,636,643,667,692,700,714,727,733,
- 750,769,778,786,800,818,833,846,857,
- 867,875,889,900,909,917,923,929,933};
- uint8_t ratios[72]={0x10,0xf1,0xe1,0xd1,0xc1,0xb1,0xa1,0x91,0x81,
- 0xf2,0x71,0xd2,0x61,0xb2,0x51,0xe3,0x92,0xd3,
- 0x41,0xf4,0xb3,0x72,0xa3,0xd4,0x31,0xe5,0xb4,
- 0x83,0xd5,0x52,0xc5,0x73,0x94,0xb5,0xd6,0xf7,
- 0x21,0xf8,0xd7,0xb6,0x95,0x74,0xc7,0x53,0xd8,
- 0x85,0xb7,0xe9,0x32,0xd9,0xa7,0x75,0xb8,0xfb,
- 0x43,0xda,0x97,0xeb,0x54,0xb9,0x65,0xdb,0x76,
- 0xfd,0x87,0x98,0xa9,0xba,0xcb,0xdc,0xed,0xfe};
- int fr = (f_fr-1)*1000;
- int i=0, i_result=0;
- int err=0, lasterr=1000;
- for(i=0; i<72; i++) {
- if(fr<errors[i]) {
- err=errors[i]-fr;
- } else {
- err=fr-errors[i];
- }
- if(err<lasterr) {
- i_result=i;
- lasterr=err;
- }
- }
- return ratios[i_result];
- }
- static uint32_t baud2divisor(unsigned int baudrate) {
- uint32_t int_ratio;
- uint32_t error;
- uint32_t dl=0;
- float f_ratio;
- float f_fr;
- float f_dl;
- float f_pclk = (float)CONFIG_CPU_FREQUENCY / CONFIG_UART_PCLKDIV;
- uint8_t fract_ratio;
- f_ratio=(f_pclk / 16 / baudrate);
- int_ratio = (int)f_ratio;
- error=(f_ratio*1000)-(int_ratio*1000);
- if(error>990) {
- int_ratio++;
- } else if(error>10) {
- f_fr=1.5;
- f_dl=f_pclk / (16 * baudrate * (f_fr));
- dl = (int)f_dl;
- f_fr=f_pclk / (16 * baudrate * dl);
- fract_ratio = uart_lookupratio(f_fr);
- }
- if(!dl) {
- return int_ratio;
- } else {
- return ((fract_ratio<<16)&0xff0000) | dl;
- }
- }
- static char txbuf[1 << CONFIG_UART_TX_BUF_SHIFT];
- static volatile unsigned int read_idx,write_idx;
- void UART_HANDLER(void) {
- int iir = UART_REGS->IIR;
- if (!(iir & 1)) {
- /* Interrupt is pending */
- switch (iir & 14) {
- #if CONFIG_UART_NUM == 1
- case 0: /* modem status */
- (void) UART_REGS->MSR; // dummy read to clear
- break;
- #endif
- case 2: /* THR empty - send */
- if (read_idx != write_idx) {
- int maxchars = 16;
- while (read_idx != write_idx && --maxchars > 0) {
- UART_REGS->THR = (unsigned char)txbuf[read_idx];
- read_idx = (read_idx+1) & (sizeof(txbuf)-1);
- }
- if (read_idx == write_idx) {
- /* buffer empty - turn off THRE interrupt */
- BITBAND(UART_REGS->IER, 1) = 0;
- }
- }
- break;
-
- case 12: /* RX timeout */
- case 4: /* data received - not implemented yet */
- (void) UART_REGS->RBR; // dummy read to clear
- break;
- case 6: /* RX error */
- (void) UART_REGS->LSR; // dummy read to clear
- default: break;
- }
- }
- }
- void uart_putc(char c) {
- if (c == '\n')
- uart_putc('\r');
- unsigned int tmp = (write_idx+1) & (sizeof(txbuf)-1) ;
- if (read_idx == write_idx && (BITBAND(UART_REGS->LSR, 5))) {
- /* buffer empty, THR empty -> send immediately */
- UART_REGS->THR = (unsigned char)c;
- } else {
- #ifdef CONFIG_UART_DEADLOCKABLE
- while (tmp == read_idx) ;
- #endif
- BITBAND(UART_REGS->IER, 1) = 0; // turn off UART interrupt
- txbuf[write_idx] = c;
- write_idx = tmp;
- BITBAND(UART_REGS->IER, 1) = 1;
- }
- }
- /* Polling version only */
- unsigned char uart_getc(void) {
- /* wait for character */
- while (!(BITBAND(UART_REGS->LSR, 0))) ;
- return UART_REGS->RBR;
- }
- /* Returns true if a char is ready */
- unsigned char uart_gotc(void) {
- return BITBAND(UART_REGS->LSR, 0);
- }
- void uart_init(void) {
- uint32_t div;
- /* Turn on power to UART */
- BITBAND(LPC_SC->PCONP, UART_PCONBIT) = 1;
- /* UART clock = CPU clock - this block is reduced at compile-time */
- if (CONFIG_UART_PCLKDIV == 1) {
- BITBAND(LPC_SC->UART_PCLKREG, UART_PCLKBIT ) = 1;
- BITBAND(LPC_SC->UART_PCLKREG, UART_PCLKBIT+1) = 0;
- } else if (CONFIG_UART_PCLKDIV == 2) {
- BITBAND(LPC_SC->UART_PCLKREG, UART_PCLKBIT ) = 0;
- BITBAND(LPC_SC->UART_PCLKREG, UART_PCLKBIT+1) = 1;
- } else if (CONFIG_UART_PCLKDIV == 4) {
- BITBAND(LPC_SC->UART_PCLKREG, UART_PCLKBIT ) = 0;
- BITBAND(LPC_SC->UART_PCLKREG, UART_PCLKBIT+1) = 0;
- } else { // Fallback: Divide by 8
- BITBAND(LPC_SC->UART_PCLKREG, UART_PCLKBIT ) = 1;
- BITBAND(LPC_SC->UART_PCLKREG, UART_PCLKBIT+1) = 1;
- }
- /* set baud rate - no fractional stuff for now */
- UART_REGS->LCR = BV(7) | 3; // always 8n1
- div = baud2divisor(CONFIG_UART_BAUDRATE);
- UART_REGS->DLL = div & 0xff;
- UART_REGS->DLM = (div >> 8) & 0xff;
- BITBAND(UART_REGS->LCR, 7) = 0;
- if (div & 0xff0000) {
- UART_REGS->FDR = (div >> 16) & 0xff;
- }
- /* reset and enable FIFO */
- UART_REGS->FCR = BV(0);
- /* enable transmit interrupt */
- BITBAND(UART_REGS->IER, 1) = 1;
- NVIC_EnableIRQ(UART_IRQ);
- UART_REGS->THR = '?';
- }
- /* --- generic code below --- */
- void uart_puthex(uint8_t num) {
- uint8_t tmp;
- tmp = (num & 0xf0) >> 4;
- if (tmp < 10)
- uart_putc('0'+tmp);
- else
- uart_putc('a'+tmp-10);
- tmp = num & 0x0f;
- if (tmp < 10)
- uart_putc('0'+tmp);
- else
- uart_putc('a'+tmp-10);
- }
- void uart_trace(void *ptr, uint16_t start, uint16_t len) {
- uint16_t i;
- uint8_t j;
- uint8_t ch;
- uint8_t *data = ptr;
- data+=start;
- for(i=0;i<len;i+=16) {
- uart_puthex(start>>8);
- uart_puthex(start&0xff);
- uart_putc('|');
- uart_putc(' ');
- for(j=0;j<16;j++) {
- if(i+j<len) {
- ch=*(data + j);
- uart_puthex(ch);
- } else {
- uart_putc(' ');
- uart_putc(' ');
- }
- uart_putc(' ');
- }
- uart_putc('|');
- for(j=0;j<16;j++) {
- if(i+j<len) {
- ch=*(data++);
- if(ch<32 || ch>0x7e)
- ch='.';
- uart_putc(ch);
- } else {
- uart_putc(' ');
- }
- }
- uart_putc('|');
- uart_putcrlf();
- start+=16;
- }
- }
- void uart_flush(void) {
- while (read_idx != write_idx) ;
- }
- void uart_puts(const char *text) {
- while (*text) {
- uart_putc(*text++);
- }
- }
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