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- #include <stdio.h>
- #include <stdlib.h>
- #include <stdint.h>
- #include "config.h"
- 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;
- }
- }
- int main(int argc, char *argv[])
- {
- if (argc != 2)
- {
- printf("usage: %s baud\n", argv[0]);
- return -1;
- }
-
- printf("Baud %d : 0x%X\n", atoi(argv[1]), baud2divisor(atoi(argv[1])));
- return 0;
- }
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