contrib/firmware/angie/c/src/serial.c

   1 // SPDX-License-Identifier: LGPL-2.1-or-later
   2
   3 /*
   4  * This code was taken from the fx2lib project from this link:
   5  * https://github.com/djmuhlestein/fx2lib
   6  *
   7  * Copyright (C) 2009 Ubixum, Inc.
   8 */
   9
  10 #include <reg_ezusb.h>
  11 #include <fx2macros.h>
  12 #include <serial.h>
  13 #include <stdint.h>
  14 /**
  15  * using the comp port implies that timer 2 will be used as
  16  * a baud rate generator.  (Don't use timer 2)
  17  **/
  18 void sio0_init(uint32_t baud_rate) __critical
  19 {
  20         uint16_t hl;     /* hl value for reload */
  21         uint8_t mult;   /* multiplier for clock speed */
  22         uint32_t tmp;   /* scratch for mult/divide */
  23
  24         mult = (CPUFREQ == CLK_12M) ? 1 : ((CPUFREQ == CLK_24M) ? 2 : 4);
  25
  26         /* set the clock rate */
  27         /* use clock 2 */
  28         RCLK = 1; TCLK = 1;
  29         tmp = mult * 375000L * 2;
  30         tmp /= baud_rate;
  31         tmp += 1;
  32         tmp /= 2;
  33         hl = 0xFFFF - (uint16_t)tmp;
  34         RCAP2H = (uint8_t)(((uint16_t)(hl) >> 8) & 0xff);
  35
  36         /* seems that the 24/48mhz calculations are always one less than suggested values */
  37   /* trm table 14-16 */
  38         RCAP2L = ((uint8_t)((uint16_t)(hl) & 0xff)) + (mult > 0 ? 1 : 0);
  39
  40   /* start the timer */
  41         TR2 = 1;
  42
  43         /* set up the serial port       */
  44         SM0 = 0; SM1 = 1; /* serial mode 1 (asyncronous)        */
  45         SM2 = 0 ;       /* has to do with receiving */
  46         REN = 1 ;       /* to enable receiving */
  47         PCON |= 0x80;    /* SET SMOD0, baud rate doubler */
  48         TI = 1;         /* we send initial byte */
  49 }
  50
  51 int getchar(void)
  52 {
  53         char c;
  54         while (!RI)
  55                 ;
  56         c = SBUF0;
  57         RI = 0;
  58         return c;
  59 }
  60
  61 void _transchar(char c)
  62 {
  63         while (!TI)
  64                 ; /* wait for TI=1 */
  65         TI = 0;
  66         SBUF0 = c;
  67 }
  68
  69 int putchar (char c)
  70 {
  71         if (c == '\n')
  72                 _transchar('\r'); /* transmit \r\n */
  73         _transchar(c);
  74         if (c == '\r')
  75                 _transchar('\n'); /* transmit \r\n */
  76         return c;
  77 }