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Demo for Glasgow Students that writes to dot matrix display and sends the display data out of the serial port
main.cpp
- Committer:
- jont
- Date:
- 2015-02-19
- Revision:
- 0:bc2c0a19b0e5
File content as of revision 0:bc2c0a19b0e5:
#include "mbed.h" /* example of driving maxim chip for Glasgow Uni Projects. Dr J.J.Trinder 2013,14,15 This one modified to also send display data out of serial port for a remote simulated display for more info email me jon.trinder@glasgow.ac.uk jont@ninelocks.com */ #define max7219_reg_noop 0x00 #define max7219_reg_digit0 0x01 #define max7219_reg_digit1 0x02 #define max7219_reg_digit2 0x03 #define max7219_reg_digit3 0x04 #define max7219_reg_digit4 0x05 #define max7219_reg_digit5 0x06 #define max7219_reg_digit6 0x07 #define max7219_reg_digit7 0x08 #define max7219_reg_decodeMode 0x09 #define max7219_reg_intensity 0x0a #define max7219_reg_scanLimit 0x0b #define max7219_reg_shutdown 0x0c #define max7219_reg_displayTest 0x0f #define LOW 0 #define HIGH 1 //serial port Serial pc(USBTX, USBRX); // tx, rx SPI max72_spi(PTD2, NC, PTD1); DigitalOut load(PTD0); //will provide the load signal char pattern_diagonal[8] = { 0x01, 0x2,0x4,0x08,0x10,0x20,0x40,0x80}; char pattern_square[8] = { 0xff, 0x81,0x81,0x81,0x81,0x81,0x81,0xff}; char pattern_star[8] = { 0x04, 0x15, 0x0e, 0x1f, 0x0e, 0x15, 0x04, 0x00}; /* Write to the maxim via SPI args register and the column data */ void write_to_max( int reg, int col) { load = LOW; // begin max72_spi.write(reg); // specify register max72_spi.write(col); // put data load = HIGH; // make sure data is loaded (on rising edge of LOAD/CS) } //writes 8 bytes to the display void pattern_to_display(char *testdata){ int cdata; for(int idx = 0; idx <= 7; idx++) { cdata = testdata[idx]; write_to_max(idx+1,cdata); //writet to the pretend display on the serial port if(pc != NULL) { pc.printf("%i;%02x\r\n", idx,cdata); } } } void setup_dot_matrix () { // initiation of the max 7219 // SPI setup: 8 bits, mode 0 max72_spi.format(8, 0); max72_spi.frequency(100000); //down to 100khx easier to scope ;-) write_to_max(max7219_reg_scanLimit, 0x07); write_to_max(max7219_reg_decodeMode, 0x00); // using an led matrix (not digits) write_to_max(max7219_reg_shutdown, 0x01); // not in shutdown mode write_to_max(max7219_reg_displayTest, 0x00); // no display test for (int e=1; e<=8; e++) { // empty registers, turn all LEDs off write_to_max(e,0); } // maxAll(max7219_reg_intensity, 0x0f & 0x0f); // the first 0x0f is the value you can set write_to_max(max7219_reg_intensity, 0x08); } void clear(){ for (int e=1; e<=8; e++) { // empty registers, turn all LEDs off write_to_max(e,0); } } int main() { pc.baud(9600); //setup serial port to 9600 setup_dot_matrix (); /* setup matric */ while(1){ //da_star(); pattern_to_display(pattern_diagonal); wait_ms(1000); pattern_to_display(pattern_square); wait_ms(1000); pattern_to_display(pattern_star); wait_ms(1000); clear(); } }