obviously, amazingly, the code seems to work...
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/* Tx master
* Raspberry Pi
* ============
* ver 0006.2
* Raspbian 8.0
*/
// (C) Helmut Wunder (HaWe) 2015
// freie Verwendung für private Zwecke
// für kommerzielle Zwecke nur nach Genehmigung durch den Autor.
// Programming language: gcc C/C++, Geany IDE
// protected under the friendly Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License
// http://creativecommons.org/licenses/by-nc-sa/3.0/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <math.h>
#include <fcntl.h>
#include <string.h>
#include <sys/ioctl.h>
#include <stdint.h>
#include <time.h>
#include <sys/time.h>
#include <errno.h>
#include "VG/openvg.h"
#include "VG/vgu.h"
#include "fontinfo.h"
#include "shapes.h"
#include "shapes_plus.h"
#include <wiringPi.h>
#include <wiringSerial.h>
#define byte uint8_t
char * uart = "/dev/ttyAMA0";
int Serial1;
//=====================================================================================
// timer
uint32_t millisec()
{
struct timeval now;
uint32_t ticks;
gettimeofday(&now, NULL);
ticks=now.tv_sec*1000+now.tv_usec/1000;
return(ticks);
}
#define millis millisec
//=====================================================================================
// openvg + shapes_plus
int _scrwidth_, _scrheight_;
#define vgHidewindow HideWindow
#define vgShowwindow End
#define vgcls() ClearWindowRGB(_scrwidth_, _scrheight_, 0, 0, 0);
#define vgStart Start
#define vgInit init
#define vgCleanup finish
int _fontsize_ = 10;
Fontinfo _font_ = MonoTypeface;
inline void setfontsize(int size) { _fontsize_ = size; }
inline void setfonttype(Fontinfo myfont) { _font_ = myfont; }
inline void lcdprintxytop(float x, float y, char * buf) {
Text(x, _scrheight_-y, buf, _font_ , _fontsize_);
}
inline void lcdprintxy(float x, float y, char * buf) {
Text(x, y, buf, _font_ , _fontsize_);
}
void vgInitgraph() {
vgInit(& _scrwidth_, & _scrheight_); // Graphics initialization
vgStart(_scrwidth_, _scrheight_); // Start the picture
vgcls();
Stroke(255, 255, 255, 1); // Set these at the start, no need to
Fill(255,255,255, 1); // keep calling them if colour hasn't changed
setfonttype(MonoTypeface);
setfontsize(20);
}
//=====================================================================================
// debug monitor
void displayvalues(int line, char * caption, uint8_t array[]) {
int cnt;
char sbuf[128];
sprintf(sbuf, "%s cks=%-4d", caption, array[1]);
//lcdprintxy(0, line, sbuf);
printf(sbuf); printf("\n");
for(cnt=0; cnt<8; ++cnt) {
sprintf(sbuf, "%3d ", array[cnt]); // print on TFT
lcdprintxy(cnt*3*8, line+10, sbuf);
printf(sbuf);
}
printf("\n");
}
//=====================================================================================
//=====================================================================================
// serial com
const uint8_t MSGSIZE=32;
uint8_t bsync=255;
uint8_t sendbuf[MSGSIZE];
uint8_t recvbuf[MSGSIZE];
uint8_t calcchecksum(uint8_t array[]) {
int32_t sum=0;
for(int i=2; i<MSGSIZE; ++i) sum+=(array[i]);
return (sum & 0x00ff);
}
bool checksumOK(uint8_t array[]){
return (calcchecksum(array)==array[1]);
}
// ================================================================
// addToBuffer and receive function courtesy of chucktodd
bool addToBuffer( uint8_t buf[], uint8_t *cnt, uint16_t timeout){
bool inSync = *cnt>0;
unsigned long start=millis();
while((*cnt<MSGSIZE)&&(millis()-start<timeout)){
if( serialDataAvail( Serial1 ) ) { // grab new char, test for sync char, if so start adding to buffer
buf[*cnt] = (uint8_t)serialGetchar( Serial1 );
if(inSync) *cnt += 1; // my origional *cnt++ was updating the pointer address, not
// the pointed to sendbuffer
else{
if(buf[*cnt]==0xFF){
inSync = true;
*cnt +=1;
}
}
}
}
return (*cnt==MSGSIZE);
}
//=====================================================================================
bool receive(uint8_t * buf, uint16_t timeout, uint8_t *cnt){ // by passing cnt in and out,
// i can timeout and still save a partial buffer, so a resync costs less (less data lost)
bool inSync=false;
unsigned long start=millis();
uint8_t * p; // pointer into buf for reSync operation
bool done=false;
do{
done = addToBuffer(buf,cnt,timeout); // if this return false, a timeout has occured, and the while will exit.
if(done){ // do checksumOK test of buffer;
done=checksumOK(buf);
if(!done){ // checksumOK failed, scan buffer for next sync char
p = (uint8_t*)memchr((buf+1),0xff,(MSGSIZE-1)); //forgot to skip the current sync at 0
if(p){ // found next sync char, shift buffer content, refill buffer
*cnt = MSGSIZE -(p-buf); // count of characters to salvage from this failure
memcpy(buf,p,*cnt); //cnt is now where the next character from Serial is stored!
}
else *cnt=0; // whole buffer is garbage
}
}
} while(!done&&(millis()-start<timeout));
return done; // if done then buf[] contains a sendbufid buffer, else a timeout occurred
}
//=====================================================================================
void loop()
{
char sbuf[128], resOK;
static uint8_t cnt=0;
uint8_t cbuf[MSGSIZE], chk;
// send to Rx slave Arduino
//Serial.println();
sendbuf[0]=bsync;
sendbuf[1]=calcchecksum(sendbuf);
for(uint8_t i=0; i<MSGSIZE; i++) { // better use write() ?
serialPutchar( Serial1, sendbuf[i]); // Send values to the Rx Arduino
}
//serialFlush( Serial1 ); // clear output buffer
//displayvalues(20, "Transmitted...: ", sendbuf);
sprintf(sbuf, "%4d %4d", sendbuf[4], sendbuf[6]);
//lcdprintxy(0, 20, sbuf);
printf(sbuf); printf("\n");
// Receive from Rx slave Arduino
memset(cbuf, 0, sizeof(cbuf));
resOK = receive ( cbuf, 10000,&cnt);
if( resOK ) { // byte 0 == syncbyte ?
cnt=0;
//displayvalues(60, "Received...:", cbuf);
chk=(byte)calcchecksum(cbuf);
memcpy(recvbuf, cbuf, sizeof(cbuf));
// change values to send back!
memcpy(sendbuf, recvbuf, sizeof(sendbuf)); // copy inbuf to outbuf
sendbuf[4]+=1; // change [4] to send back
}
}
//=====================================================================================
int main() {
unsigned long timesav;
char sbuf[128];
char instr[128];
printf("initializing..."); printf("\n");
// UART Serial com port
Serial1 = serialOpen (uart, 115200); // for Arduino code compatibility reasons
while(1) { loop(); }
serialClose( Serial1);
exit(0);
}
//=====================================================================================
//=====================================================================================
