sdcc/device/lib/ds390/rtc390.c

   1 /*-------------------------------------------------------------------------
   2    rtc390.c - rtc routines for the DS1315 (tested on TINI)
   3
   4    Copyright (C) 2001, Johan Knol <johan.knol AT iduna.nl>
   5
   6    This library is free software; you can redistribute it and/or modify it
   7    under the terms of the GNU General Public License as published by the
   8    Free Software Foundation; either version 2, or (at your option) any
   9    later version.
  10
  11    This library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this library; see the file COPYING. If not, write to the
  18    Free Software Foundation, 51 Franklin Street, Fifth Floor, Boston,
  19    MA 02110-1301, USA.
  20
  21    As a special exception, if you link this library with other files,
  22    some of which are compiled with SDCC, to produce an executable,
  23    this library does not by itself cause the resulting executable to
  24    be covered by the GNU General Public License. This exception does
  25    not however invalidate any other reasons why the executable file
  26    might be covered by the GNU General Public License.
  27 -------------------------------------------------------------------------*/
  28
  29 #include <tinibios.h>
  30 #include <stdio.h>
  31 #include <time.h>
  32 #include <ctype.h>
  33
  34 /* this is the address of the ds1315 phantom time chip, although
  35    it doesn't really matter as long as it's in the 300000-3fffff
  36    range since the chip only uses CE3*
  37 */
  38
  39 __xdata static volatile unsigned char __at (0x310000) rtc;
  40
  41 // this is the 64bit pattern that has to be recognized by the ds1315
  42 __code unsigned char rtcMagic[8]={0xc5,0x3a,0xa3,0x5c,0xc5,0x3a,0xa3,0x5c};
  43
  44 #define BCDtoINT(x) (((x)&0x0f)+((x)>>4)*10)
  45 #define INTtoBCD(x) (((x)%10)+(((x)/10)<<4))
  46
  47 static void RtcSync(void) {
  48   unsigned char dummy, byte,bitMask;
  49
  50   // reset rtc chip
  51   dummy=rtc;
  52
  53   // say the magic word
  54   for (byte=0; byte<8; byte++) {
  55     for (bitMask=0x01; bitMask; bitMask<<=1) {
  56       rtc = (rtcMagic[byte]&bitMask) ? 0xff : 0x00;
  57     }
  58   }
  59 }
  60
  61 unsigned char RtcRead(struct tm *rtcDate) {
  62   unsigned char rtcBytes[8];
  63   unsigned char byte,bitMask;
  64
  65   RtcSync();
  66
  67   for (byte=0; byte<8; byte++) {
  68     rtcBytes[byte]=0;
  69     for (bitMask=0x01; bitMask; bitMask<<=1) {
  70       if (rtc&1) {
  71         rtcBytes[byte]|=bitMask;
  72       }
  73     }
  74   }
  75   rtcDate->tm_year=BCDtoINT(rtcBytes[7])+100; // year since 1900
  76   rtcDate->tm_mon=BCDtoINT(rtcBytes[6])-1; // jan=0
  77   rtcDate->tm_mday=BCDtoINT(rtcBytes[5]);
  78   rtcDate->tm_wday=(rtcBytes[4]&0x07)-1; // monday=0?
  79   rtcDate->tm_hour=BCDtoINT(rtcBytes[3]);
  80   rtcDate->tm_min=BCDtoINT(rtcBytes[2]);
  81   rtcDate->tm_sec=BCDtoINT(rtcBytes[1]);
  82   rtcDate->tm_hundredth=BCDtoINT(rtcBytes[0]);
  83   if ((rtcBytes[4]&0x30) || (rtcBytes[3]&0x80)) {
  84     //oscillator not running, reset not active or in 12h mode
  85     return 0;
  86   }
  87   return 1;
  88 }
  89
  90 void RtcWrite(struct tm *rtcDate) {
  91   unsigned char rtcBytes[8];
  92   unsigned char byte,bitMask;
  93
  94   rtcBytes[7]=INTtoBCD(rtcDate->tm_year%100);
  95   rtcBytes[6]=INTtoBCD(rtcDate->tm_mon)+1;
  96   rtcBytes[5]=INTtoBCD(rtcDate->tm_mday);
  97   rtcBytes[4]=(INTtoBCD(rtcDate->tm_wday)+1)&0x07; //set 24h  mode
  98   rtcBytes[3]=INTtoBCD(rtcDate->tm_hour)&0x3f; // oscillator on, reset on
  99   rtcBytes[2]=INTtoBCD(rtcDate->tm_min);
 100   rtcBytes[1]=INTtoBCD(rtcDate->tm_sec);
 101   //rtcBytes[0]=INTtoBCD(rtcDate->hundredth);
 102   rtcBytes[0]=0;
 103
 104   RtcSync();
 105
 106   for (byte=0; byte<8; byte++) {
 107     for (bitMask=0x01; bitMask; bitMask<<=1) {
 108       rtc = (rtcBytes[byte]&bitMask) ? 0xff : 0x00;
 109     }
 110   }
 111 }