cerebrum_firmware.c

   1 #include <avr/io.h>
   2 #include <util/delay.h>
   3 #include <avr/pgmspace.h>
   4 #include <avr/interrupt.h>
   5 #include "uart.h"
   6
   7 void setup(void);
   8 void loop(void);
   9
  10 int main(void){
  11     setup();
  12     for(;;) loop();
  13 }
  14
  15 void setup(){
  16     uart_init(UART_BAUD_SELECT_DOUBLE_SPEED(115201, F_CPU));
  17     //software PWM init FIXME
  18     DDRH |= 0x20;
  19     PORTH |= 0x20;
  20     sei();
  21 }
  22
  23 //this scary construct is in place to make the compiler happy. if you know a better way, feel free to improve.
  24 uint8_t _frameBuffer[] = {0,0,0,0};
  25 uint8_t _secondFrameBuffer[] = {0,0,0,0};
  26 uint8_t* frameBuffer = _frameBuffer;
  27 uint8_t* secondFrameBuffer = _secondFrameBuffer;
  28 char nbuf;
  29 int state = 0;
  30 uint8_t switch_last_state = 0;
  31 int switch_debounce_timeout = 0;
  32 uint8_t mcnt = 0;
  33 uint8_t ccnt = 0;
  34
  35 uint8_t pwm_cycle = 0;
  36 uint8_t pwm_val[4];
  37
  38 void swapBuffers(void){
  39     uint8_t* tmp = frameBuffer;
  40     frameBuffer = secondFrameBuffer;
  41     secondFrameBuffer = tmp;
  42 }
  43
  44 void setLED(int num, int val){
  45     if(num<32){
  46         frameBuffer[num>>3] &= ~(1<<(num&7));
  47         if(val)
  48             frameBuffer[num>>3] |= 1<<(num&7);
  49     }
  50 }
  51
  52 int parseHex(char* buf){
  53     int result = 0;
  54     int len = 2;
  55     for(int i=0; i<len; i++){
  56         char c = buf[len-i];
  57         int v = 0;
  58         if(c>='0' && c<='9'){
  59             v=(c-'0');
  60         }else if(c>='a' && c<= 'f'){
  61             v=(c-'a'+10);
  62         }else if(c>='A' && c<= 'F'){
  63             v=(c-'A'+10);
  64         }
  65         result |= v<<(4*i);
  66     }
  67     return result;
  68 }
  69
  70 void loop(){ //one frame
  71     static uint8_t escape_state = 0;
  72     uint16_t receive_status = 1;
  73     //primitive somewhat messy state machine of the uart interface
  74     do{ //Always empty the receive buffer since there are _delay_xxs in the following code and thus this might not run all that often.
  75         receive_status = uart_getc();
  76         char c = receive_status&0xFF;
  77         receive_status &= 0xFF00;
  78         //eats three commands: 's' (0x73) led value                     sets led number [led] to [value]
  79         //                     'b' (0x62) buffer buffer buffer buffer   sets the whole frame buffer
  80         //                     'a' (0x61) meter value                   sets analog meter number [meter] to [value]
  81         if(!receive_state){
  82             if(!escape_state){
  83                 receive_state |= 0x02;
  84                 if(c == '\\'){
  85                     escape_state = 1;
  86                 }else if(c == '\n'){
  87                     state = 0;
  88                 }
  89             }else{
  90                 receive_state = 0;
  91                 escape_state = 0;
  92                 switch(c){
  93                     case '\\':
  94                         break;
  95                     case 'n':
  96                         c = '\n';
  97                         break;
  98                 }
  99             }
 100         }
 101         if(!receive_status){
 102             switch(state){
 103                 case 0: //Do not assume anything about the variables used
 104                     switch(c){
 105                         case 's':
 106                             state = 2;
 107                             break;
 108                         case 'b':
 109                             nbuf = 0;
 110                             state = 4;
 111                             break;
 112                         case 'a':
 113                             state = 5;
 114                             nbuf = 0;
 115                             break;
 116                     }
 117                     break;
 118                 case 2:
 119                     nbuf=c;
 120                     state = 3;
 121                     break;
 122                 case 3:
 123                     setLED(nbuf, c);
 124                     state = 0;
 125                     break;
 126                 case 4:
 127                     secondFrameBuffer[(uint8_t) nbuf] = c;
 128                     nbuf++;
 129                     if(nbuf == 4){
 130                         swapBuffers();
 131                         state = 0;
 132                     }
 133                     break;
 134                 case 5:
 135                     nbuf = c;
 136                     state = 6;
 137                     if(nbuf >= 4) //prevent array overflows
 138                         nbuf = 0;
 139                     break;
 140                 case 6:
 141                     pwm_val[(uint8_t) nbuf] = c;
 142                     state = 0;
 143             }
 144         }
 145     }while(!receive_status);
 146     for(int i=0; i<8; i++){
 147         uint8_t Q = 0x80>>i; //select the currently active "row" of the matrix. On the protoboards I make, this actually corresponds to physical traces.
 148         //de-packing of frame data: data is packed like this: [11111117][22222266][33333555][4444----]
 149         if(!(i&4))
 150             Q |= frameBuffer[i&3] >> i;
 151         else
 152             Q |= frameBuffer[i&3] & (0xFF << (i&3));
 153         //equivalent to the code above: <== revisiting this, I'm not quite sure about this anymore.
 154         //Q |= frameBuffer[i&3]>>(i&(0x30>>(i&4))) & (0xFF<<(i&(0x30>>(!i&4))));
 155         PORTD &= 0x0F;
 156         PORTD |= Q&0xF0;
 157         PORTB &= 0xF0;
 158         PORTB |= Q&0x0F;
 159         _delay_ms(1); //Should result in >100Hz refresh rate
 160     }
 161 }