/*
tlc5940.c
Raspberry Pi driving the TLC5940
to compile : cc tlc5940.c -o tlc5940 -lwiringPi
*/
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include <time.h>
#include <wiringPi.h>
#define SCLK 0
#define
SIN 1
#define VPRG 2
#define XLAT 3
#define BLANK 4
#define GSCLK 5
#define Digs 3
#define D0 10
int firstCycleFlag=1;
static const uint8_t segmentDigits [] =
{
// a b c d e f g
p Segments
// 0 1 2 3 4 5 6
7 wiringPi pin No.
1, 1, 1, 1, 1, 1, 0,
0, // 0
0, 1, 1, 0, 0, 0, 0,
0, // 1
1, 1, 0, 1, 1, 0, 1,
0, // 2
1, 1, 1, 1, 0, 0, 1,
0, // 3
0, 1, 1, 0, 0, 1, 1,
0, // 4
1, 0, 1, 1, 0, 1, 1,
0, // 5
1, 0, 1, 1, 1, 1, 1,
0, // 6
1, 1, 1, 0, 0, 0, 0,
0, // 7
1, 1, 1, 1, 1, 1, 1,
0, // 8
1, 1, 1, 1, 0, 1, 1,
0, // 9
1, 1, 1, 0, 1, 1, 1,
0, // A
0, 0, 1, 1, 1, 1, 1,
0, // b
1, 0, 0, 1, 1, 1, 0,
0, // C
0, 1, 1, 1, 1, 0, 1,
0, // d
1, 0, 0, 1, 1, 1, 1,
0, // E
1, 0, 0, 0, 1, 1, 1,
0, // F
0, 0, 0, 0, 0, 0, 0,
0, // blank
} ;
static void TLC5940pulse(int port)
{
digitalWrite(port,HIGH);
digitalWrite(port,LOW);
}
static void TLC5940sendDC(unsigned char * dcdata)
{
int i,j;
int pos;
unsigned char wk[16];
unsigned int mask;
pos=15;
for(i=0;i<16;i++) {
wk[pos--]=dcdata[i];
}
digitalWrite(VPRG,HIGH);
digitalWrite(XLAT,LOW);
for(i=0;i<16;i++) {
for(j=6;j>0;j--) {
mask=1<<(j-1);
if (wk[i] & mask)
digitalWrite(SIN, 1);
else
digitalWrite(SIN, 0);
TLC5940pulse(SCLK);
}
}
TLC5940pulse(XLAT);
}
static void TLC5940sendGS(unsigned short * gsdata)
{
int i,j;
int pos;
unsigned short wk[16];
unsigned int mask;
pos=15;
for(i=0;i<16;i++) {
wk[pos--]=gsdata[i];
}
digitalWrite(VPRG,LOW);
digitalWrite(XLAT,LOW);
for(i=0;i<16;i++) {
for(j=12;j>0;j--) {
mask=1<<(j-1);
if (wk[i] & mask)
digitalWrite(SIN, 1);
else
digitalWrite(SIN, 0);
TLC5940pulse(SCLK);
TLC5940pulse(GSCLK);
}
}
digitalWrite(BLANK,HIGH);
TLC5940pulse(XLAT);
digitalWrite(BLANK,LOW);
if (firstCycleFlag) {
TLC5940pulse(SCLK);
firstCycleFlag=0;
}
}
static void TLC5940feedPorts(int cnt)
{
int loop;
int i;
for (loop=0;loop<cnt;loop++) {
TLC5940pulse(BLANK);
for(i=0;i<4096;i++){
TLC5940pulse(GSCLK);
}
}
}
static void DisplayDigit (char digit, unsigned short*
gsdata)
{
int i;
uint8_t segment ;
uint8_t index, d, segVal ;
d = toupper (digit) ;
if ((d >= '0') && (d <=
'9')) // Digit
index = d - '0' ;
else if ((d >= 'A') && (d <=
'F')) // Hex
index = d - 'A' + 10 ;
else
index = 16
;
// Blank
for (segment = 0 ; segment < 8 ; ++segment) {
segVal = segmentDigits [index * 8 +
segment] ;
if(segVal)
gsdata[segment] = 0xfff;
else
gsdata[segment] = 0x0;
}
}
static void DisplayDigits (char* digits, unsigned short*
gsdata)
{
uint8_t digit ;
char c1 ;
for (digit = 0 ; digit < Digs; ++digit) {
digitalWrite (D0 + digit, 1) ;
c1 = digits [digit] ;
DisplayDigit(c1,gsdata);
TLC5940sendGS(gsdata);
TLC5940feedPorts(1);
digitalWrite (D0 + digit, 0) ;
}
}
main(){
int i,j;
unsigned char dcval;
unsigned int gsval;
unsigned char dcdata[16];
unsigned short gsdata[16];
char digits[8];
if (wiringPiSetup () == -1) exit(1);
pinMode(SCLK, OUTPUT);
pinMode(SIN, OUTPUT);
pinMode(VPRG, OUTPUT);
pinMode(XLAT, OUTPUT);
pinMode(BLANK, OUTPUT);
pinMode(GSCLK, OUTPUT);
digitalWrite(SCLK,LOW);
digitalWrite(XLAT,LOW);
digitalWrite(BLANK,HIGH);
digitalWrite(GSCLK,LOW);
for(i=0;i<Digs;i++) {
pinMode(D0+i, OUTPUT);
digitalWrite(D0+i, 0);
}
//Send DC Data
dcval=0x0f;
for(i=0;i<16;i++){
dcdata[i]=dcval;
}
TLC5940sendDC(dcdata);
//Clear GS Data
gsval=0x0;
for(i=0;i<16;i++){
gsdata[i]=gsval;
}
//Set GS Data
strcpy(digits,"123");
for(i=0;i<1000;i++)
DisplayDigits(digits,gsdata);
strcpy(digits,"ABC");
for(i=0;i<1000;i++)
DisplayDigits(digits,gsdata);
digitalWrite(SCLK,LOW);
digitalWrite(XLAT,LOW);
digitalWrite(BLANK,LOW);
digitalWrite(GSCLK,LOW);
exit(0);
}
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