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// Code to copy a MCM font file to the Arduino + Max7456 OSD//// MAX7456_font Sketch// at 9600 baud it take about 3min to download a mcm file// http://www.maxim-ic.com/tools/evkit/index.cfm?EVKit=558// max7456 evaluation kit software#define DATAOUT 11//11-MOSI#define DATAIN 12//12-MISO#define SPICLOCK 13//13-sck#define MAX7456SELECT 6 //6#define USBSELECT 10//10-ss#define VSYNC 2// INT0//MAX7456 opcodes#define VM0_reg 0x00#define VM1_reg 0x01#define DMM_reg 0x04#define DMAH_reg 0x05#define DMAL_reg 0x06#define DMDI_reg 0x07#define CMM_reg 0x08#define CMAH_reg 0x09#define CMAL_reg 0x0A#define CMDI_reg 0x0B#define STAT_reg 0xA0//MAX7456 commands#define CLEAR_display 0x04#define CLEAR_display_vert 0x06#define END_string 0xff#define WRITE_nvr 0xa0// with NTSC#define ENABLE_display 0x08#define ENABLE_display_vert 0x0c#define MAX7456_reset 0x02#define DISABLE_display 0x00// with PAL// all VM0_reg commands need bit 6 set//#define ENABLE_display 0x48//#define ENABLE_display_vert 0x4c//#define MAX7456_reset 0x42//#define DISABLE_display 0x40#define WHITE_level_80 0x03#define WHITE_level_90 0x02#define WHITE_level_100 0x01#define WHITE_level_120 0x00#define MAX_font_rom 0xff#define STATUS_reg_nvr_busy 0x20#define NVM_ram_size 0x36// with NTSC#define MAX_screen_rows 0x0d //13// with PAL//#define MAX_screen_rows 0x10 //16volatile byte screen_buffer[MAX_font_rom];volatile byte character_bitmap[0x40];volatile byte ascii_binary[0x08];volatile byte bit_count;volatile byte byte_count;volatile int font_count;volatile int incomingByte;volatile int count;//////////////////////////////////////////////////////////////void setup(){byte spi_junk;int x;Serial.begin(38400);Serial.flush();digitalWrite(USBSELECT,HIGH); //disable USB chippinMode(MAX7456SELECT,OUTPUT);digitalWrite(MAX7456SELECT,HIGH); //disable devicepinMode(DATAOUT, OUTPUT);pinMode(DATAIN, INPUT);pinMode(SPICLOCK,OUTPUT);pinMode(VSYNC, INPUT);// SPCR = 01010000//interrupt disabled,spi enabled,msb 1st,master,clk low when idle,//sample on leading edge of clk,system clock/4 rate (4 meg)SPCR = (1<<SPE)|(1<<MSTR);spi_junk=SPSR;spi_junk=SPDR;delay(250);// force soft reset on Max7456digitalWrite(MAX7456SELECT,LOW);spi_transfer(VM0_reg);spi_transfer(MAX7456_reset);digitalWrite(MAX7456SELECT,HIGH);delay(500);// set all rows to same character white level, 90%digitalWrite(MAX7456SELECT,LOW);for (x = 0; x < MAX_screen_rows; x++){spi_transfer(x + 0x10);spi_transfer(WHITE_level_90);}// make sure the Max7456 is enabledspi_transfer(VM0_reg);spi_transfer(ENABLE_display);digitalWrite(MAX7456SELECT,HIGH);incomingByte = 0;count = 0;bit_count = 0;byte_count = 0;font_count = 0;//display all 256 internal MAX7456 charactersfor (x = 0; x < MAX_font_rom; x++){screen_buffer[x] = x;}count = MAX_font_rom;write_new_screen();Serial.println("Ready for text file download");Serial.println("");delay(100);}//////////////////////////////////////////////////////////////void loop(){byte x;if (Serial.available() > 0){// read the incoming byte:incomingByte = Serial.read();switch(incomingByte) // parse and decode mcm file{case 0x0d: // carridge return, end of line//Serial.println("cr");if (bit_count == 8 && (ascii_binary[0] == 0x30 || ascii_binary[0] == 0x31)){// turn 8 ascii binary bytes to single byte '01010101' = 0x55// fill in 64 bytes of character datacharacter_bitmap[byte_count] = decode_ascii_binary();byte_count++;bit_count = 0;}elsebit_count = 0;break;case 0x0a: // line feed, ignore//Serial.println("ln");break;case 0x30: // ascii '0'case 0x31: // ascii '1'ascii_binary[bit_count] = incomingByte;bit_count++;break;default:break;}}// we have one completed character// write the character to NVMif(byte_count == 64){write_NVM();byte_count = 0;font_count++;}// we have burned all 256 characters in NVMif(font_count == 256){font_count = 0;// force soft reset on Max7456digitalWrite(MAX7456SELECT,LOW);spi_transfer(VM0_reg);spi_transfer(MAX7456_reset);digitalWrite(MAX7456SELECT,HIGH);delay(500);// display all 256 new internal MAX7456 charactersfor (x = 0; x < MAX_font_rom; x++){screen_buffer[x] = x;}count = MAX_font_rom;write_new_screen();Serial.println("");Serial.println("Done with file download");}}//////////////////////////////////////////////////////////////byte spi_transfer(volatile byte data){SPDR = data; // Start the transmissionwhile (!(SPSR & (1<<SPIF))) // Wait the end of the transmission{};return SPDR; // return the received byte}//////////////////////////////////////////////////////////////void write_new_screen(){int x, local_count;byte char_address_hi, char_address_lo;byte screen_char;local_count = count;char_address_hi = 0;char_address_lo = 60; // start on third line//Serial.println("write_new_screen");// clear the screendigitalWrite(MAX7456SELECT,LOW);spi_transfer(DMM_reg);spi_transfer(CLEAR_display);digitalWrite(MAX7456SELECT,HIGH);// disable displaydigitalWrite(MAX7456SELECT,LOW);spi_transfer(VM0_reg);spi_transfer(DISABLE_display);spi_transfer(DMM_reg); //dmm//spi_transfer(0x21); //16 bit trans backgroundspi_transfer(0x01); //16 bit trans w/o backgroundspi_transfer(DMAH_reg); // set start address highspi_transfer(char_address_hi);spi_transfer(DMAL_reg); // set start address lowspi_transfer(char_address_lo);x = 0;while(local_count) // write out full screen{screen_char = screen_buffer[x];spi_transfer(DMDI_reg);spi_transfer(screen_char);x++;local_count--;}spi_transfer(DMDI_reg);spi_transfer(END_string);spi_transfer(VM0_reg); // turn on screen next verticalspi_transfer(ENABLE_display_vert);digitalWrite(MAX7456SELECT,HIGH);}//////////////////////////////////////////////////////////////byte decode_ascii_binary(){byte ascii_byte;ascii_byte = 0;if (ascii_binary[0] == 0x31) // ascii '1'ascii_byte = ascii_byte + 128;if (ascii_binary[1] == 0x31)ascii_byte = ascii_byte + 64;if (ascii_binary[2] == 0x31)ascii_byte = ascii_byte + 32;if (ascii_binary[3] == 0x31)ascii_byte = ascii_byte + 16;if (ascii_binary[4] == 0x31)ascii_byte = ascii_byte + 8;if (ascii_binary[5] == 0x31)ascii_byte = ascii_byte + 4;if (ascii_binary[6] == 0x31)ascii_byte = ascii_byte + 2;if (ascii_binary[7] == 0x31)ascii_byte = ascii_byte + 1;//Serial.print(ascii_byte, HEX);return(ascii_byte);}//////////////////////////////////////////////////////////////void write_NVM(){byte x;byte char_address_hi, char_address_lo;byte screen_char;char_address_hi = font_count;char_address_lo = 0;//Serial.println("write_new_screen");// disable displaydigitalWrite(MAX7456SELECT,LOW);spi_transfer(VM0_reg);spi_transfer(DISABLE_display);spi_transfer(CMAH_reg); // set start address highspi_transfer(char_address_hi);for(x = 0; x < NVM_ram_size; x++) // write out 54 (out of 64) bytes of character to shadow ram{screen_char = character_bitmap[x];spi_transfer(CMAL_reg); // set start address lowspi_transfer(x);spi_transfer(CMDI_reg);spi_transfer(screen_char);}// transfer a 54 bytes from shadow ram to NVMspi_transfer(CMM_reg);spi_transfer(WRITE_nvr);// wait until bit 5 in the status register returns to 0 (12ms)while ((spi_transfer(STAT_reg) & STATUS_reg_nvr_busy) != 0x00);spi_transfer(VM0_reg); // turn on screen next verticalspi_transfer(ENABLE_display_vert);digitalWrite(MAX7456SELECT,HIGH);}