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

Dependencies:   FastPWM

Dependents:   TLC5940LEDtreiber

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TLC5940Mux Class Reference

TLC5940Mux Class Reference

This class allows a TLC5940 to be multiplexed. More...

#include <TLC5940.h>

Inherits TLC5940.

Public Member Functions

 TLC5940Mux (PinName SCLK, PinName MOSI, PinName GSCLK, PinName BLANK, PinName XLAT, PinName DCPRG, PinName VPRG, const int number, const int rows, void(*SetRows)(int))
 Set up the TLC5940.
unsigned short * operator= (unsigned short *data)
 Set the contents of the buffer that contains the multiplexed data.
unsigned short * operator[] (int index)
 Get a pointer to one of the rows of the multiplexed data.

Private Member Functions

void setNewGSData (unsigned short *data)
 Set the next chunk of grayscale data to be sent.
void setNewDCData (unsigned char *data)
 Set the next chunk of dot correction data to be sent.

Detailed Description

This class allows a TLC5940 to be multiplexed.

It inherits the TLC5940 class and uses it to control the TLC5940 driver(s). It does not support sending dot corection data. This class sets the new grayscale data every iteration of the GSCLK reset loop. It then updates the current row using the user defined function SetRows. The framerate you will recieve using this function can be calculate by: 1 / (((1/GSCLK_SPEED) * 4096) * rows). I reccomend maintaining a framerate above 30fps. However, keep in mind that as your framerate increases, so does your CPU usage.

Using the TLC5940Mux class to control an 8x8 LED matrix:

  #include "mbed.h"
  #include "TLC5940.h"
  // Bus connecting to the rows of the LED matrix through PNP transistors
  BusOut rows(p22, p23, p24, p25, p26, p27, p28, p29);
  // Function to update the rows using the BusOut class
  void SetRows(int nextRow)
      // I am using PNP transistors, so inversion is necessary
      rows = ~(1 << nextRow);
  // Create the TLC5940Mux instance
  TLC5940Mux tlc(p7, p5, p21, p9, p10, p11, p12, 1, 8, &SetRows);
  int main()
      tlc[0][0] = 0xFFF; // Turn on the top left LED

Definition at line 180 of file TLC5940.h.

Constructor & Destructor Documentation

TLC5940Mux ( PinName  SCLK,
PinName  MOSI,
PinName  GSCLK,
PinName  BLANK,
PinName  XLAT,
PinName  DCPRG,
PinName  VPRG,
const int  number,
const int  rows,
void(*)(int)  SetRows 

Set up the TLC5940.

SCLK- The SCK pin of the SPI bus
MOSI- The MOSI pin of the SPI bus
GSCLK- The GSCLK pin of the TLC5940(s)
BLANK- The BLANK pin of the TLC5940(s)
XLAT- The XLAT pin of the TLC5940(s)
DCPRG- The DCPRG pin of the TLC5940(s)
VPRG- The VPRG pin of the TLC5940(s)
number- The number of TLC5940s (if you are daisy chaining)
rows- The number of rows you are multiplexing
SetRows- The function pointer to your function that sets the current row.
The SetRows function allows you to set exactly how you want your rows to be updated. The TLC5940Mux class calls this function with an argument of int that contains the number of the row to be turned on. If the TLC5940Mux class needs the first row to be turned on, the int will be 0.

Definition at line 5 of file TLC5940Mux.cpp.

Member Function Documentation

unsigned short * operator= ( unsigned short *  data )

Set the contents of the buffer that contains the multiplexed data.

data- The data to set to the buffer containing 16 12 bit grayscale data chunks per TLC5940
The data provided

Definition at line 26 of file TLC5940Mux.cpp.

unsigned short * operator[] ( int  index )

Get a pointer to one of the rows of the multiplexed data.

index- The row that you would like the contents of
A pointer to the data containing the requested row containing 16 12 bit grayscale data chunks per TLC5940
This operator can also be used to change or get the value of an individual LED. For example:
  TLC5940Mux[0][0] = 0xFFF;

Definition at line 34 of file TLC5940Mux.cpp.