Spencer Davis / TLC5940

This library allows control of the TLC5940 PWM driver IC. It supports both normal operation and controlling multiplexed displays.

Dependencies:   FastPWM

Dependents:   TLC5940LEDtreiber

TLC5940.h@0:be9399a34b15, 2013-05-20 (annotated)

Committer:
Spencer
Date:
Mon May 20 19:07:01 2013 +0000
Revision:
0:be9399a34b15
Child:
1:013a9737441d
This library allows control of the TLC5940 PWM driver IC.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
Spencer 0:be9399a34b15 1 #ifndef TLC5940_H
Spencer 0:be9399a34b15 2 #define TLC5940_H
Spencer 0:be9399a34b15 3
Spencer 0:be9399a34b15 4 #include "FastPWM.h"
Spencer 0:be9399a34b15 5 /*
Spencer 0:be9399a34b15 6
Spencer 0:be9399a34b15 7 ASCII art cat(why not?):
Spencer 0:be9399a34b15 8 /\_/\
Spencer 0:be9399a34b15 9 ____/ o o \
Spencer 0:be9399a34b15 10 /~____ =ø= /
Spencer 0:be9399a34b15 11 (______)__m_m)
Spencer 0:be9399a34b15 12
Spencer 0:be9399a34b15 13 */
Spencer 0:be9399a34b15 14
Spencer 0:be9399a34b15 15 /**
Spencer 0:be9399a34b15 16 * SPI speed used by the mbed to communicate with the TLC5940
Spencer 0:be9399a34b15 17 * The TLC5940 supports up to 30Mhz. This should be kept as high
Spencer 0:be9399a34b15 18 * as possible to ensure that data has time to be sent each reset cycle.
Spencer 0:be9399a34b15 19 */
Spencer 0:be9399a34b15 20 #define SPI_SPEED 30000000
Spencer 0:be9399a34b15 21
Spencer 0:be9399a34b15 22 /**
Spencer 0:be9399a34b15 23 * The rate at which the GSCLK pin is pulsed
Spencer 0:be9399a34b15 24 * This also controls how often the reset function is called
Spencer 0:be9399a34b15 25 * The rate at which the reset function is called can be calculated by: (1/GSCLK_SPEED) * 4096
Spencer 0:be9399a34b15 26 * The maximum reliable rate is around ~32Mhz. I reccomend keeping this as low as possible because
Spencer 0:be9399a34b15 27 * a higher rate will use more CPU. Also, this must be low enough to give time for sending new data
Spencer 0:be9399a34b15 28 * before the completion of a GSCLK cycle (4096 pulses). If you are daisy chaining multiple TLC5940s,
Spencer 0:be9399a34b15 29 * divide 32Mhz by the number of chips to get a good maximum rate.
Spencer 0:be9399a34b15 30 */
Spencer 0:be9399a34b15 31 #define GSCLK_SPEED 2500000
Spencer 0:be9399a34b15 32
Spencer 0:be9399a34b15 33 /**
Spencer 0:be9399a34b15 34 * This class controls a TLC5940 PWM driver IC.
Spencer 0:be9399a34b15 35 * It supports sending dot correction and grayscale data. However, it does not support error checking or writing the EEPROM.
Spencer 0:be9399a34b15 36 * This class uses the FastPWM library by Erik Olieman to continuously pulse the GSLCK pin without CPU intervention. After
Spencer 0:be9399a34b15 37 * 4096 pulses, the private member funciton reset is called by the ticker. It resets the display by pulsing the BLANK pin. If new
Spencer 0:be9399a34b15 38 * data has been set to be sent by the functions setNewGSData or setNewDCData, it is sent here. The definition GSCLK_SPEED in TLC5940.h
Spencer 0:be9399a34b15 39 * controls how often this function is called. A higher GSCLK_SPEED will increase the rate at which the screen is updated but also increase
Spencer 0:be9399a34b15 40 * CPU time spent in that function. The default value is 1Mhz. The rate at which the reset function is called can be calculated by:
Spencer 0:be9399a34b15 41 * (1/GSCLK_SPEED) * 4096.
Spencer 0:be9399a34b15 42 *
Spencer 0:be9399a34b15 43 * Using the TLC5940 to control an LED:
Spencer 0:be9399a34b15 44 * @code
Spencer 0:be9399a34b15 45 * #include "mbed.h"
Spencer 0:be9399a34b15 46 * #include "TLC5940.h"
Spencer 0:be9399a34b15 47 *
Spencer 0:be9399a34b15 48 * // Create the TLC5940 instance
Spencer 0:be9399a34b15 49 * TLC5940 tlc(p7, p5, p21, p9, p10, p11, p12, 1);
Spencer 0:be9399a34b15 50 *
Spencer 0:be9399a34b15 51 * int main()
Spencer 0:be9399a34b15 52 * {
Spencer 0:be9399a34b15 53 * // Create a buffer to store the data to be sent
Spencer 0:be9399a34b15 54 * unsigned short GSData[16] = { 0x0000 };
Spencer 0:be9399a34b15 55 *
Spencer 0:be9399a34b15 56 * // Enable the first LED
Spencer 0:be9399a34b15 57 * GSData[0] = 0xFFF;
Spencer 0:be9399a34b15 58 *
Spencer 0:be9399a34b15 59 * // Set the new data
Spencer 0:be9399a34b15 60 * tlc.setNewGSData(GSData);
Spencer 0:be9399a34b15 61 *
Spencer 0:be9399a34b15 62 * while(1)
Spencer 0:be9399a34b15 63 * {
Spencer 0:be9399a34b15 64 *
Spencer 0:be9399a34b15 65 * }
Spencer 0:be9399a34b15 66 * }
Spencer 0:be9399a34b15 67 * @endcode
Spencer 0:be9399a34b15 68 */
Spencer 0:be9399a34b15 69 class TLC5940
Spencer 0:be9399a34b15 70 {
Spencer 0:be9399a34b15 71 public:
Spencer 0:be9399a34b15 72 /**
Spencer 0:be9399a34b15 73 * Set up the TLC5940
Spencer 0:be9399a34b15 74 * @param SCLK - The SCK pin of the SPI bus
Spencer 0:be9399a34b15 75 * @param MOSI - The MOSI pin of the SPI bus
Spencer 0:be9399a34b15 76 * @param GSCLK - The GSCLK pin of the TLC5940(s)
Spencer 0:be9399a34b15 77 * @param BLANK - The BLANK pin of the TLC5940(s)
Spencer 0:be9399a34b15 78 * @param XLAT - The XLAT pin of the TLC5940(s)
Spencer 0:be9399a34b15 79 * @param DCPRG - The DCPRG pin of the TLC5940(s)
Spencer 0:be9399a34b15 80 * @param VPRG - The VPRG pin of the TLC5940(s)
Spencer 0:be9399a34b15 81 * @param number - The number of TLC5940s (if you are daisy chaining)
Spencer 0:be9399a34b15 82 */
Spencer 0:be9399a34b15 83 TLC5940(PinName SCLK, PinName MOSI, PinName GSCLK, PinName BLANK,
Spencer 0:be9399a34b15 84 PinName XLAT, PinName DCPRG, PinName VPRG, const int number = 1);
Spencer 0:be9399a34b15 85
Spencer 0:be9399a34b15 86 /**
Spencer 0:be9399a34b15 87 * Set the next chunk of grayscale data to be sent
Spencer 0:be9399a34b15 88 * @param data - Array of 16 bit shorts containing 16 12 bit grayscale data chunks per TLC5940
Spencer 0:be9399a34b15 89 * @note These must be in intervals of at least (1/GSCLK_SPEED) * 4096 to be sent
Spencer 0:be9399a34b15 90 */
Spencer 0:be9399a34b15 91 void setNewGSData(unsigned short* data);
Spencer 0:be9399a34b15 92
Spencer 0:be9399a34b15 93 /**
Spencer 0:be9399a34b15 94 * Set the next chunk of dot correction data to be sent
Spencer 0:be9399a34b15 95 * @param data - Array of 8 bit chars containing 16 6 bit dot correction data chunks per TLC5940
Spencer 0:be9399a34b15 96 * @note These must be in intervals of at least (1/GSCLK_SPEED) * 4096 to be sent. Also, this function is optional. If you do not
Spencer 0:be9399a34b15 97 * use it, then the TLC5940 will use the EEPROM, which (by default) conatins the data 0x3F.
Spencer 0:be9399a34b15 98 */
Spencer 0:be9399a34b15 99 void setNewDCData(unsigned char* data);
Spencer 0:be9399a34b15 100
Spencer 0:be9399a34b15 101 protected:
Spencer 0:be9399a34b15 102 /**
Spencer 0:be9399a34b15 103 * Set the next chunk of grayscale data to be sent while in the current reset cycle
Spencer 0:be9399a34b15 104 * @note This is useful to send the next set of data right after the first is finished being displayed.
Spencer 0:be9399a34b15 105 * The primary purpose for this is multiplexing, although it could be used for anything else.
Spencer 0:be9399a34b15 106 */
Spencer 0:be9399a34b15 107 virtual void setNextData() {}
Spencer 0:be9399a34b15 108
Spencer 0:be9399a34b15 109
Spencer 0:be9399a34b15 110 // Number of TLC5940s in series
Spencer 0:be9399a34b15 111 const int number;
Spencer 0:be9399a34b15 112
Spencer 0:be9399a34b15 113 private:
Spencer 0:be9399a34b15 114 // SPI port - only MOSI and SCK are used
Spencer 0:be9399a34b15 115 SPI spi;
Spencer 0:be9399a34b15 116
Spencer 0:be9399a34b15 117 // PWM output using the FastPWM library by Erik Olieman
Spencer 0:be9399a34b15 118 FastPWM gsclk;
Spencer 0:be9399a34b15 119
Spencer 0:be9399a34b15 120 // Digital out pins used for the TLC5940
Spencer 0:be9399a34b15 121 DigitalOut blank;
Spencer 0:be9399a34b15 122 DigitalOut xlat;
Spencer 0:be9399a34b15 123 DigitalOut dcprg;
Spencer 0:be9399a34b15 124 DigitalOut vprg;
Spencer 0:be9399a34b15 125
Spencer 0:be9399a34b15 126 // Call a reset function to manage sending data and GSCLK updating
Spencer 0:be9399a34b15 127 Ticker reset_ticker;
Spencer 0:be9399a34b15 128
Spencer 0:be9399a34b15 129 // Has new GS/DC data been loaded?
Spencer 0:be9399a34b15 130 volatile bool newGSData;
Spencer 0:be9399a34b15 131 volatile bool newDCData;
Spencer 0:be9399a34b15 132
Spencer 0:be9399a34b15 133 // Do we need to send an XLAT pulse? (Was GS data clocked in last reset?)
Spencer 0:be9399a34b15 134 volatile bool need_xlat;
Spencer 0:be9399a34b15 135
Spencer 0:be9399a34b15 136 // Buffers to store data until it is sent
Spencer 0:be9399a34b15 137 unsigned short* gsBuffer;
Spencer 0:be9399a34b15 138 unsigned char* dcBuffer;
Spencer 0:be9399a34b15 139
Spencer 0:be9399a34b15 140 // Function to reset the display and send the next chunks of data
Spencer 0:be9399a34b15 141 void reset();
Spencer 0:be9399a34b15 142 };
Spencer 0:be9399a34b15 143
Spencer 0:be9399a34b15 144
Spencer 0:be9399a34b15 145 /**
Spencer 0:be9399a34b15 146 * This class allows a TLC5940 to be multiplexed.
Spencer 0:be9399a34b15 147 * It inherits the TLC5940 class and uses it to control the TLC5940 driver(s). It does not support sending dot corection data.
Spencer 0:be9399a34b15 148 * This class sets the new grayscale data every iteration of the GSCLK reset loop. It then updates the current row using the
Spencer 0:be9399a34b15 149 * user defined function SetRows. The framerate you will recieve using this function can be calculate by: 1 / (((1/GSCLK_SPEED) * 4096) * rows).
Spencer 0:be9399a34b15 150 * I reccomend maintaining a framerate above 30fps. However, keep in mind that as your framerate increases, so does your CPU usage.
Spencer 0:be9399a34b15 151 *
Spencer 0:be9399a34b15 152 * Using the TLC5940Mux class to control an 8x8 LED matrix:
Spencer 0:be9399a34b15 153 * @code
Spencer 0:be9399a34b15 154 * #include "mbed.h"
Spencer 0:be9399a34b15 155 * #include "TLC5940.h"
Spencer 0:be9399a34b15 156 *
Spencer 0:be9399a34b15 157 * // Bus connecting to the rows of the LED matrix through PNP transistors
Spencer 0:be9399a34b15 158 * BusOut rows(p22, p23, p24, p25, p26, p27, p28, p29);
Spencer 0:be9399a34b15 159 *
Spencer 0:be9399a34b15 160 * // Function to update the rows using the BusOut class
Spencer 0:be9399a34b15 161 * void SetRows(int nextRow)
Spencer 0:be9399a34b15 162 * {
Spencer 0:be9399a34b15 163 * // I am using PNP transistors, so inversion is necessary
Spencer 0:be9399a34b15 164 * rows = ~(1 << nextRow);
Spencer 0:be9399a34b15 165 * }
Spencer 0:be9399a34b15 166 *
Spencer 0:be9399a34b15 167 * // Create the TLC5940Mux instance
Spencer 0:be9399a34b15 168 * TLC5940Mux tlc(p7, p5, p21, p9, p10, p11, p12, 1, 8, &SetRows);
Spencer 0:be9399a34b15 169 *
Spencer 0:be9399a34b15 170 * int main()
Spencer 0:be9399a34b15 171 * {
Spencer 0:be9399a34b15 172 * tlc[0][0] = 0xFFF; // Turn on the top left LED
Spencer 0:be9399a34b15 173 * while(1)
Spencer 0:be9399a34b15 174 * {
Spencer 0:be9399a34b15 175 *
Spencer 0:be9399a34b15 176 * }
Spencer 0:be9399a34b15 177 * }
Spencer 0:be9399a34b15 178 * @endcode
Spencer 0:be9399a34b15 179 */
Spencer 0:be9399a34b15 180 class TLC5940Mux : private TLC5940
Spencer 0:be9399a34b15 181 {
Spencer 0:be9399a34b15 182 public:
Spencer 0:be9399a34b15 183 /**
Spencer 0:be9399a34b15 184 * Set up the TLC5940
Spencer 0:be9399a34b15 185 * @param SCLK - The SCK pin of the SPI bus
Spencer 0:be9399a34b15 186 * @param MOSI - The MOSI pin of the SPI bus
Spencer 0:be9399a34b15 187 * @param GSCLK - The GSCLK pin of the TLC5940(s)
Spencer 0:be9399a34b15 188 * @param BLANK - The BLANK pin of the TLC5940(s)
Spencer 0:be9399a34b15 189 * @param XLAT - The XLAT pin of the TLC5940(s)
Spencer 0:be9399a34b15 190 * @param DCPRG - The DCPRG pin of the TLC5940(s)
Spencer 0:be9399a34b15 191 * @param VPRG - The VPRG pin of the TLC5940(s)
Spencer 0:be9399a34b15 192 * @param number - The number of TLC5940s (if you are daisy chaining)
Spencer 0:be9399a34b15 193 * @param rows - The number of rows you are multiplexing
Spencer 0:be9399a34b15 194 * @param SetRows - The function pointer to your function that sets the current row.
Spencer 0:be9399a34b15 195 * @note The SetRows function allows you to set exactly how you want your rows
Spencer 0:be9399a34b15 196 * to be updated. The TLC5940Mux class calls this function with an argument of int that contains the number of the row to
Spencer 0:be9399a34b15 197 * be turned on. If the TLC5940Mux class needs the first row to be turned on, the int will be 0.
Spencer 0:be9399a34b15 198 */
Spencer 0:be9399a34b15 199 TLC5940Mux(PinName SCLK, PinName MOSI, PinName GSCLK, PinName BLANK,
Spencer 0:be9399a34b15 200 PinName XLAT, PinName DCPRG, PinName VPRG, const int number,
Spencer 0:be9399a34b15 201 const int rows, void (*SetRows)(int));
Spencer 0:be9399a34b15 202
Spencer 0:be9399a34b15 203 // Destructor used to delete memory
Spencer 0:be9399a34b15 204 ~TLC5940Mux();
Spencer 0:be9399a34b15 205
Spencer 0:be9399a34b15 206 /**
Spencer 0:be9399a34b15 207 * Set the contents of the buffer that contains the multiplexed data
Spencer 0:be9399a34b15 208 * @param data - The data to set to the buffer containing 16 12 bit grayscale data chunks per TLC5940
Spencer 0:be9399a34b15 209 * @returns The data provided
Spencer 0:be9399a34b15 210 */
Spencer 0:be9399a34b15 211 unsigned short* operator=(unsigned short* data);
Spencer 0:be9399a34b15 212
Spencer 0:be9399a34b15 213 /**
Spencer 0:be9399a34b15 214 * Get a pointer to one of the rows of the multiplexed data
Spencer 0:be9399a34b15 215 * @param index - The row that you would like the contents of
Spencer 0:be9399a34b15 216 * @returns A pointer to the data containing the requested row containing 16 12 bit grayscale data chunks per TLC5940
Spencer 0:be9399a34b15 217 * @note This operator can also be used to change or get the value of an individual LED.
Spencer 0:be9399a34b15 218 * For example:
Spencer 0:be9399a34b15 219 * @code
Spencer 0:be9399a34b15 220 * TLC5940Mux[0][0] = 0xFFF;
Spencer 0:be9399a34b15 221 * @endcode
Spencer 0:be9399a34b15 222 */
Spencer 0:be9399a34b15 223 unsigned short* operator[](int index);
Spencer 0:be9399a34b15 224
Spencer 0:be9399a34b15 225 private:
Spencer 0:be9399a34b15 226 // Virtual function overriden from TLC5940 class
Spencer 0:be9399a34b15 227 virtual void setNextData();
Spencer 0:be9399a34b15 228
Spencer 0:be9399a34b15 229 // Number of rows
Spencer 0:be9399a34b15 230 const int rows;
Spencer 0:be9399a34b15 231
Spencer 0:be9399a34b15 232 // Function to set the current row
Spencer 0:be9399a34b15 233 void (*SetRows)(int);
Spencer 0:be9399a34b15 234
Spencer 0:be9399a34b15 235 // The current row
Spencer 0:be9399a34b15 236 int index;
Spencer 0:be9399a34b15 237
Spencer 0:be9399a34b15 238 // Buffer containing data to be sent during each frame
Spencer 0:be9399a34b15 239 unsigned short* dataBuffer;
Spencer 0:be9399a34b15 240 };
Spencer 0:be9399a34b15 241
Spencer 0:be9399a34b15 242 #endif