Just found that by going through the adafruit install rtc install it’s working again. Hopefully this info will prove useful to others.

Thanks for all your hard work.

Jon

Keith,

I am rather sure it is not that simple code needed to make an ATTiny 2313 listening as a slave to the master RPi. Googling for “AVR i2c slave library” will lead you to apropriate pages for free download.

Next challenge could be that RPi is not enabled for clock stretching, so you will have to slow down i2C-speed dramatically ?

Regards
Karl

Hi Gordon,

thanks for your library.
I append a small i2c test program. It may be useful for quick test of their i2c devices or as another example for your library.

With Best Regards,

tmm

/*
* Copyright (c) 2013 tmm GPL
***********************************************************************

gcc -O3 -Wall -I/usr/local/include -Winline -pipe -L/usr/local/lib i2ctst.c -lwiringPi -lpthread -lm -o i2ctst

*/

#include
#include
#include

#include
#include

int GetNum(char *str)
{
int a;
int b;
b = (sscanf(str, “%i”, &a) == 0);
if (b != 0) a = -1;
return a;
}

int main(int argc,
char *argv[])
{
int i,n;
int j=0;
int fd = -1;
int adr = -1;
int dly = -1;
int reg = -1;
int ver = 0;
int dat = -1;
int err;
for (i = 1; i =0) fd = wiringPiI2CSetup((adr&0xff)>>1);
if (ver) printf(“open res=%d for slaveadr %02x\n”, fd, adr);
break;
case ‘v’: ver = 1-ver;
break;
case ‘p’: dly = GetNum(&argv[i][2]);
if (dly>=0) delay(dly);
break;
case ‘a’: reg = GetNum(&argv[i][2]);
break;
case ‘r’: n = GetNum(&argv[i][2]);
if (fd>=0) {
if (n==0) dat = wiringPiI2CRead(fd);
else if (n==1) dat = wiringPiI2CReadReg8(fd, reg & 0xff);
else if (n==2) dat = wiringPiI2CReadReg16(fd, reg & 0xff);
printf(“0x%x %d\n”, dat, dat);
}
case ‘w’: dat = GetNum(&argv[i][2]);
if (fd>=0) {
err = wiringPiI2CWrite(fd, dat & 0xff);
if (ver) printf(“writing %02x to slavenr %02x result:%d\n”, dat, adr, err);
}
break;
case ‘1’: dat = GetNum(&argv[i][2]);
if (fd>=0) {
err = wiringPiI2CWriteReg8(fd, reg, dat & 0xff);
if (ver) printf(“writing %02x to slavenr %02x result:%d\n”, dat, adr, err);
}
break;
case ‘2’: dat = GetNum(&argv[i][2]);
if (fd>=0) {
err = wiringPiI2CWriteReg16(fd, reg, dat & 0xffff);
if (ver) printf(“writing %02x to slavenr %02x result:%d\n”, dat, adr, err);
}
break;
case ‘h’: printf(
” -h this help (and exit)\n”
” -v toggles verbosity (default off)\n”
” -dXX select device with i2caddress XX\n”
” -pXX wait for XX milliseconds\n”
” -aXX set register to XX\n”
” -rX read device X:0=byte 1=register byte 2=register word\n”
” -1XX write 8bit data XX to device and register\n”
” -2XX write 16bit data XX to device and register\n”
” -wXX write 8bit data XX to device\n”
” XX write 8bit data XX to device\n”
“\n”
“e.g.: ./i2c -v -d0x40 0x55 -w1000 0xAA -r0 -w1000 0xff # PCF8574\n”
” ./i2c -v -d0x44 -a0 -20×1234\n”
);
exit(0);
break;
}
}
else {
dat = GetNum(&argv[i][0]);
if (fd>=0) {
err = wiringPiI2CWrite(fd, dat & 0xff);
if (ver) printf(“writing %02x to slavenr %02x result:%d\n”, dat, adr, err);
}
}
}

return 0;
}

Hello Gordon,

great library, but I don’t know how to setup a working I2C conversation to my 7 Segment driver SAA1064. Which function should I use? I tried wiringPiI2CWriteReg8 and wiringPiI2CWriteReg16, unfortunately i get always “-1”. wiringPiI2CSetup works return is “3”.

With this shell command: sudo i2cset -y 1 0x38 0x00 0x17 0x06 0x4F 0x5B 0x7F i
I get something displayed on the four 7 segment displays.

C code:
int main (void)
{ int ok;
ok = wiringPiI2CSetup(0x38);
printf(“%d \n”,ok);
//ok = wiringPiI2CWriteReg16(0x0017, 0x064F, 0x5B00);
ok = wiringPiI2CWriteReg8(0x00, 0x00, 0x0000);
printf(“%d \n”,ok);
}

Andreas

Hello,
i’m using archlinux, i can use i2cdetect and i2cset with my MCP23008 to enabled LED.
I build wiringPi but i receive this: “the wiringpi i2c helper librtaries will not be built.”

So, when i compile C files with this command: “gcc fichier.c -o exec -lwiringPi”
i receive this nevertheless i declared #include in C file.

“undefined reference to ‘wiringPiI2CSetup’
undefined reference to ‘wiringPiI2CWriteReg8’ ”

I don’t understand.

If you can help me please.
Cordially.

Hi Gordon,

First of all, thanks a lot for the library and support.

I am using this library for interfacing 3-Axis Acceleration sensor Ic (MMA7660),which is based on I2C communication protocol. Device ID 0x4c, verified with $ i2cdetect -y 1
Here are some important lines from my code….

if(wiringPisetup() == -1)
error msg;
if( (fd=wiringPiI2CSetup(0x4c)) = 0) // oxo7 : mode register, 0x01 : for active mode
printf(“Mode set as : Active”);

while(1)
{
x = wiringPiI2CReadReg8(fd, 0x00); // 0x00 : for X-axis value
y = wiringPiI2CReadReg8(fd, 0x01); // 0x01 : for Y-axis value
z = wiringPiI2CReadReg8(fd, 0x02); // 0x02 : for Z-axis value

printf(” x=%d, y=%d, z=%d”, x,y,z);
}

But while executing it, it is giving me all the three values same which is nothing but the value of X-axis only, i have verified it but tilting the acceleration sensor in all three directions, it changes only X-axis values, and same value for Y & Z .

Probably it is reading X-axis register (0x00) only, even when we are sending 0x01 & 0x02 for Y & Z respectively.

if you have any clue or suggestion regarding this problem, please help me out.

Thanks in Advance.

ref. compiling wiringPiI2C-libraries

i have on my raspberry pi 2 wiringPi-libraries
– 1) wiringPi-98bcb20
– 2) wiringPi-25895a8 the newest version, i think

in the moment i write a program with your wiringPiI2C-library
and the L3G4200D

i included

i compile my programm with :
gcc -o l3g4200d-wp-1 l3g4200d-wp-1.c -lwiringPi

then i have following errors
/tmp/ccFufjMn.o: In function `main’:
l3g4200d-wp-1.c:(.text+0x248): undefined reference to `wringPiI2CReadReg16′
l3g4200d-wp-1.c:(.text+0x268): undefined reference to `wringPiI2CWriteReg16′
l3g4200d-wp-1.c:(.text+0x288): undefined reference to `wringPiI2CWriteReg16′
l3g4200d-wp-1.c:(.text+0x2a8): undefined reference to `wringPiI2CWriteReg16′
/tmp/ccFufjMn.o: In function `setupL3G4200D’:
l3g4200d-wp-1.c:(.text+0x3ac): undefined reference to `wringPiI2CWriteReg16′
l3g4200d-wp-1.c:(.text+0x3cc): undefined reference to `wringPiI2CWriteReg16′
/tmp/ccFufjMn.o:l3g4200d-wp-1.c:(.text+0x3ec): more undefined references to `wringPiI2CWriteReg16′ follow
collect2: ld returned 1 exit status

i read the posting from jishnu_oman on 21.february 2013 on your
side

you wrote when this happend:
– sudo apt-get install lib2c-dev
– remake wiringPi
– ./build clean; ./build
all done

but after a new compile: the same errors are idented
its possible that the error comes from my 2 libraries ???

excuse my bad english.
thanks for help, hints and tricks.
regards stephan

hi gordon,
what are you thinking about my code?
regards stephan

I am always getting a return of -1 whenever I read or write from any register on the MMA8452Q. I have heard that this accelerometer has problems with i2c because it has a repeat start signal. This is my code. I don’t see where the issue is. The device id is always 0x1d.

#include
#include
#include
#include
#include
using namespace std;

int main()
{
cout << "hello world\n";
int fd = wiringPiI2CSetup(0x1d);
//status reg
int e = wiringPiI2CReadReg8(fd,0x00);
//data config reg
int d = wiringPiI2CWriteReg8(fd, 0x0e, 0x00) ;
cout << fd << " " << e << " " << d << "\n";

Gordon,
I am looking to use your library (or the Python port of it) but I am planning to install a DS3231 RTC on P5 ( i2c-0 on second rev board), I saw comments that there were problems using both i2c busses ( I plan to use the other bus to drive port expanders to control 48 relays), is this possible? Or do I need to find another way to access the RTC outside of your library?
Thanks
Ben.

Hi Gordon,

Thanks for the excellent library – I’m using it with a c# wrapper in Mono applications (tho that’s not really relevant to what I’m going to ask!) and it’s make my life a whole lot easier.

My current pet project is trying to use an i2c broadcast radio tuner (it’s the SI 4735), for which I need to both read and write data in lumps of more than 2 bytes and using registers. I’m wondering what the best way to do this is – should I do an initial register read/write and then a series of registerless generic read/writes to get or set the remaining bytes of the i2c slave response or command, or should I add some more methods to the library i2c class?

Thanks again for the superb library!
Regards,
Mike

wiringPiNewNode: Pin 100 overlaps with existing definition

I can’t seem to resolve the problem above. Can I can some help please?