ROM2/display_basic.c

   1 /*
   2  * display_basic.c - simple functions for writing to the screen of the vendie.
   3  *
   4  * Use set_msg(char[10]) to write a new message to the screen, replacing the
   5  * previous one.
   6  *
   7  */
   8
   9 #include "display_basic.h"
  10 #include "vend.h"
  11
  12 /* private prototypes */
  13 void display_send_byte(char c);
  14 void display_reset();
  15
  16 void set_msg(char newmsg[11]) {
  17         int i;
  18         int prevchar = 0;
  19
  20         //display_reset();
  21         spi_enable();
  22         for (i=0; i < 10; i++) {
  23                 if (newmsg[i] == 0) break;
  24         }
  25         display_send_byte(0xaf); // reset ptr to start
  26         for (i--; i >= 0; i--) {
  27                 if (prevchar && newmsg[i] == 0x2E) {
  28                         display_send_byte(newmsg[i]&0x7f);
  29                         continue;
  30                 }
  31
  32                 // check if next character is a period
  33                 if (newmsg[i] == 0x2E) {
  34                         prevchar = newmsg[i];
  35                         continue;
  36                 }
  37
  38                 if (prevchar) {
  39                         display_send_byte(newmsg[i]&0x7f);
  40                         display_send_byte(prevchar&0x7f);
  41                         prevchar = 0;
  42                         continue;
  43                 }
  44
  45                 if (newmsg[i] == 0) break;
  46
  47                 display_send_byte(newmsg[i]&0x7f);
  48         }
  49
  50         if (prevchar) {
  51                 display_send_byte(prevchar&0x7f);
  52         }
  53         spi_disable();
  54 }
  55
  56 void display_send_byte(char c) {
  57         bset_misc_output(A3800_DISPLAY_WRITE);  /* enable the display clock */
  58
  59         _io_ports[M6811_SPDR] = c;                  /* load SPI with byte */
  60         while(!(_io_ports[M6811_SPSR]&M6811_SPIF)); /* wait for completion */
  61         _io_ports[M6811_SPDR];                      /* SPDR read to clear SPIF flag */
  62
  63         bclr_misc_output(A3800_DISPLAY_WRITE);  /* disable the display clock */
  64 }
  65
  66 #define DISPLAY_DELAY  20 /* ms to delay between ops - could be tweaked */
  67 void display_reset() {
  68         /* lower the reset line for a while */
  69         bclr((void*)&_io_ports[M6811_PORTA], PORTA_DISP_RESET);
  70         delay(DISPLAY_DELAY);
  71         bset((void*)&_io_ports[M6811_PORTA], PORTA_DISP_RESET);
  72         delay(DISPLAY_DELAY);
  73
  74         spi_enable();
  75
  76         display_send_byte(0xC0 | 10);    /* tell the controller there are 10 digits */
  77         //display_send_byte(0xE0);    /* set duty cycle to 0%                  */
  78         display_send_byte(0xFF);    /* set duty cycle to 100%                */
  79
  80         spi_disable();
  81 }
  82
  83 void display_init() {
  84         display_reset();
  85 }
  86