slaveTest.cpp
#include <pigpio.h>
#include <iostream>
using namespace std;
void runSlave();
void closeSlave();
int getControlBits(int, bool);
const int slaveAddress = 0x03; // <-- Your address of choice
bsc_xfer_t xfer; // Struct to control data flow
int main(){
// Chose one of those two lines (comment the other out):
runSlave();
//closeSlave();
return 0;
}
void runSlave() {
gpioInitialise();
cout << "Initialized GPIOs\n";
// Close old device (if any)
xfer.control = getControlBits(slaveAddress, false); // To avoid conflicts when restarting
bscXfer(&xfer);
// Set I2C slave Address to 0x0A
xfer.control = getControlBits(slaveAddress, true);
int status = bscXfer(&xfer); // Should now be visible in I2C-Scanners
if (status >= 0)
{
cout << "Opened slave\n";
xfer.rxCnt = 0;
while(1){
bscXfer(&xfer);
if(xfer.rxCnt > 0) {
cout << "Received " << xfer.rxCnt << " bytes: ";
for(int i = 0; i < xfer.rxCnt; i++)
cout << xfer.rxBuf[i];
cout << "\n";
}
//if (xfer.rxCnt > 0){
// cout << xfer.rxBuf;
//}
}
}else
cout << "Failed to open slave!!!\n";
}
void closeSlave() {
gpioInitialise();
cout << "Initialized GPIOs\n";
xfer.control = getControlBits(slaveAddress, false);
bscXfer(&xfer);
cout << "Closed slave.\n";
gpioTerminate();
cout << "Terminated GPIOs.\n";
}
int getControlBits(int address /* max 127 */, bool open) {
/*
Excerpt from http://abyz.me.uk/rpi/pigpio/cif.html#bscXfer regarding the control bits:
22 21 20 19 18 17 16 15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 00
a a a a a a a - - IT HC TF IR RE TE BK EC ES PL PH I2 SP EN
Bits 0-13 are copied unchanged to the BSC CR register. See pages 163-165 of the Broadcom
peripherals document for full details.
aaaaaaa defines the I2C slave address (only relevant in I2C mode)
IT invert transmit status flags
HC enable host control
TF enable test FIFO
IR invert receive status flags
RE enable receive
TE enable transmit
BK abort operation and clear FIFOs
EC send control register as first I2C byte
ES send status register as first I2C byte
PL set SPI polarity high
PH set SPI phase high
I2 enable I2C mode
SP enable SPI mode
EN enable BSC peripheral
*/
// Flags like this: 0b/*IT:*/0/*HC:*/0/*TF:*/0/*IR:*/0/*RE:*/0/*TE:*/0/*BK:*/0/*EC:*/0/*ES:*/0/*PL:*/0/*PH:*/0/*I2:*/0/*SP:*/0/*EN:*/0;
int flags;
if(open)
flags = /*RE:*/ (1 << 9) | /*TE:*/ (1 << 8) | /*I2:*/ (1 << 2) | /*EN:*/ (1 << 0);
else // Close/Abort
flags = /*BK:*/ (1 << 7) | /*I2:*/ (0 << 2) | /*EN:*/ (0 << 0);
return (address << 16 /*= to the start of significant bits*/) | flags;
}
Links
https://raspberrypi.stackexchange.com/questions/76109/raspberry-as-an-i2c-slave