We decided to control the 9x5 LED matrix using 14 digital outputs on the Arduino Micro because it simplified the hardware design.
/* RS232_MATRIX_CONTROL_v2p0 Single character driver for LED matrix display. Current code is hardcoded to display 46 characters on a 9 row by 5 column matrix. Each character is sent through serial terminal followed by a carriage return. Jovan Trujillo Arizona State University 03/27/2013 */ byte RN[] = {4,5,6,7,8,9,10,11,12}; byte CN[] = {23,22,21,20,19}; byte LED = 13; byte strobe = 2; // strobe rate for each row of matrix in milliseconds. byte inByte = 0; // Input character received from serial port. byte idx = 0; // Generic index counter. byte i = 0; // Generic index counter. int exposure = 250; // Number of times entire character is displayed. // Exposure time is calculated to be: strobe x # rows x exposure byte rowcnt = 9; // Number of rows to display for matrix arrays that have fewer than 9 rows. // Character database contains the column bit patterns for each row in an array. // Character database is hardcoded for a 9x5 LED matrix. byte D_0[] = {17,14,14,12,10,6,14,14,17}; // 1 byte D_1[] = {3,27,27,27,27,26,26,26,0}; // 2 byte D_2[] = {17,14,30,30,30,17,15,15,16}; // 3 byte D_3[] = {1,30,30,30,17,30,30,30,1}; // 4 byte D_4[] = {15,15,14,14,14,0,30,30,30}; // 5 byte D_5[] = {16,23,23,23,16,30,30,14,17}; // 6 byte D_6[] = {23,15,15,15,15,0,14,14,0}; // 7 byte D_7[] = {0,14,30,30,29,27,27,27,27}; // 8 byte D_8[] = {17,21,21,21,0,14,14,14,0}; // 9 byte D_9[] = {0,14,14,0,30,30,30,30,29}; // 10 byte D_A[] = {27,21,14,14,14,0,14,14,14}; // 11 byte D_B[] = {1,14,14,14,1,14,14,14,1}; // 12 byte D_C[] = {24,23,15,15,15,15,15,23,24}; // 13 byte D_D[] = {3,21,22,22,22,22,22,21,3}; // 14 byte D_E[] = {0,15,15,15,3,15,15,15,0}; // 15 byte D_F[] = {0,15,15,3,15,15,15,15,15}; // 16 byte D_G[] = {24,23,15,15,15,12,14,14,17}; // 17 byte D_H[] = {14,14,14,14,0,14,14,14,14}; // 18 byte D_I[] = {0,27,27,27,27,27,27,27,0}; // 19 byte D_J[] = {30,30,30,30,30,30,14,14,17}; // 20 byte D_K[] = {14,13,11,7,15,7,11,13,14}; // 21 byte D_L[] = {15,15,15,15,15,15,15,15,0}; // 22 byte D_M[] = {14,4,10,10,10,14,14,14,14}; // 23 byte D_N[] = {14,6,6,10,10,10,12,12,14}; // 24 byte D_O[] = {27,21,14,14,14,14,14,21,27}; // 25 byte D_P[] = {1,14,14,14,1,15,15,15,15}; // 26 byte D_Q[] = {30,26,22,14,14,14,10,9,22}; // 27 byte D_R[] = {1,14,14,1,15,7,11,13,14}; // 28 byte D_S[] = {17,14,15,23,27,29,30,14,17}; // 29 byte D_T[] = {0,10,27,27,27,27,27,27,27}; // 30 byte D_U[] = {14,14,14,14,14,14,14,14,0}; // 31 byte D_V[] = {14,14,14,14,14,14,14,21,27}; // 32 byte D_W[] = {14,14,14,10,10,10,10,10,21}; // 33 byte D_X[] = {14,14,14,21,27,21,14,14,14}; // 34 byte D_Y[] = {14,14,14,21,27,27,27,27,27}; // 35 byte D_Z[] = {0,30,30,21,27,21,15,15,0}; // 36 byte COLON[] = {31,17,17,17,31,17,17,17,31}; // 37 byte SEMICOLON[] = {17,17,17,31,17,17,17,25,23}; // 38 byte LESSTHAN[] = {30,29,27,23,15,23,27,29,30}; // 39 byte EQUAL[] = {31,31,0,31,31,31,0,31,31}; // 40 byte GRTRTHAN[] = {15,23,27,29,30,29,27,23,15}; // 41 byte QUESTION[] = {17,14,30,25,27,27,31,27,31}; // 42 byte D_AT[] = {31,0,14,8,10,8,15,0,31}; // 43 byte D_DASH[] = {31,31,31,0,0,0,31,31,31}; // 44 byte D_SPC[] = {31,31,31,31,31,31,31,31,31}; // 45 byte D_PER[] = {31,31,31,31,31,31,17,17,17}; // 46 byte D_BLK[] = {0,0,0,0,0,0,0,0,0}; // 47 char datalist[47]; // datalist holds an array of all available chracters to pattern match. byte *decodelist[47]; // decodelist holds an array of memory references to the bit patterns for each character. byte *refval = 0; // refval contains a reference to the bit pattern for a specific character entered through the serial terminal. // the setup routine runs once when you press reset: void setup() { // Initialize datalist with valid characters. datalist[0] = '0'; datalist[1] = '1'; datalist[2] = '2'; datalist[3] = '3'; datalist[4] = '4'; datalist[5] = '5'; datalist[6] = '6'; datalist[7] = '7'; datalist[8] = '8'; datalist[9] = '9'; datalist[10] = 'A'; datalist[11] = 'B'; datalist[12] = 'C'; datalist[13] = 'D'; datalist[14] = 'E'; datalist[15] = 'F'; datalist[16] = 'G'; datalist[17] = 'H'; datalist[18] = 'I'; datalist[19] = 'J'; datalist[20] = 'K'; datalist[21] = 'L'; datalist[22] = 'M'; datalist[23] = 'N'; datalist[24] = 'O'; datalist[25] = 'P'; datalist[26] = 'Q'; datalist[27] = 'R'; datalist[28] = 'S'; datalist[29] = 'T'; datalist[30] = 'U'; datalist[31] = 'V'; datalist[32] = 'W'; datalist[33] = 'X'; datalist[34] = 'Y'; datalist[35] = 'Z'; datalist[36] = ':'; datalist[37] = ';'; datalist[38] = '<'; datalist[39] = '='; datalist[40] = '>'; datalist[41] = '?'; datalist[42] = '@'; datalist[43] = '-'; datalist[44] = ' '; datalist[45] = '.'; datalist[46] = '*'; // Initialize decodelist with references to the bit patterns for valid characters. decodelist[0] = D_0; decodelist[1] = D_1; decodelist[2] = D_2; decodelist[3] = D_3; decodelist[4] = D_4; decodelist[5] = D_5; decodelist[6] = D_6; decodelist[7] = D_7; decodelist[8] = D_8; decodelist[9] = D_9; decodelist[10] = D_A; decodelist[11] = D_B; decodelist[12] = D_C; decodelist[13] = D_D; decodelist[14] = D_E; decodelist[15] = D_F; decodelist[16] = D_G; decodelist[17] = D_H; decodelist[18] = D_I; decodelist[19] = D_J; decodelist[20] = D_K; decodelist[21] = D_L; decodelist[22] = D_M; decodelist[23] = D_N; decodelist[24] = D_O; decodelist[25] = D_P; decodelist[26] = D_Q; decodelist[27] = D_R; decodelist[28] = D_S; decodelist[29] = D_T; decodelist[30] = D_U; decodelist[31] = D_V; decodelist[32] = D_W; decodelist[33] = D_X; decodelist[34] = D_Y; decodelist[35] = D_Z; decodelist[36] = COLON; decodelist[37] = SEMICOLON; decodelist[38] = LESSTHAN; decodelist[39] = EQUAL; decodelist[40] = GRTRTHAN; decodelist[41] = QUESTION; decodelist[42] = D_AT; decodelist[43] = D_DASH; decodelist[44] = D_SPC; decodelist[45] = D_PER; decodelist[46] = D_BLK; // Initialize serial and wait for port to open: Serial.begin(9600); Serial.println("Started...\n"); // initialize the digital pin as an output. pinMode(4, OUTPUT); pinMode(5, OUTPUT); pinMode(6, OUTPUT); pinMode(7, OUTPUT); pinMode(8, OUTPUT); pinMode(9, OUTPUT); pinMode(10, OUTPUT); pinMode(11, OUTPUT); pinMode(12, OUTPUT); pinMode(19, OUTPUT); pinMode(20, OUTPUT); pinMode(21, OUTPUT); pinMode(22, OUTPUT); pinMode(23, OUTPUT); // Initialize LED matrix to OFF state. This will have to change for different array dimensions. for (i=0; i<=8; i++) { digitalWrite(RN[i], HIGH); } for (i=0; i<=4; i++) { digitalWrite(CN[i], LOW); } } // the loop routine runs over and over again forever: void loop() { // read from port 3 // TODO: Need to shut off serial port if using pins 0 and 1 for digital I/O while (Serial.available() > 0) { inByte = Serial.read(); // Find serial input character in datalist and set refval to bit pattern reference based on datalist index. if (Serial.read() == '\r') { idx = exposure; for (i=0; i<=46; i++) { if (datalist[i] == inByte) { idx = i; } } refval = decodelist[idx]; if (idx != exposure) { idx = 0; } // Write bit pattern to LED matrix. while (idx < exposure) { for (i=0; i<rowcnt; i++) { digitalWrite(RN[i], LOW); digitalWrite(CN[4], !bitRead(refval[i],4)); digitalWrite(CN[3], !bitRead(refval[i],3)); digitalWrite(CN[2], !bitRead(refval[i],2)); digitalWrite(CN[1], !bitRead(refval[i],1)); digitalWrite(CN[0], !bitRead(refval[i],0)); delay(strobe); digitalWrite(RN[i],HIGH); } digitalWrite(RN[i], HIGH); digitalWrite(CN[0], LOW); digitalWrite(CN[1], LOW); digitalWrite(CN[2], LOW); digitalWrite(CN[3], LOW); digitalWrite(CN[4], LOW); idx = idx + 1; } Serial.println(inByte, DEC); } } }
