todbot/softi2cmaster

Software I2C / TWI library for Arduino allows any two pins to be SDA & SCL

softi2cmaster's Issues

CC-BY-SA 3.0 license compatibility with LGPL & GPL license.

It is my understanding that CC-BY-SA 3.0 is not compatible with LGPL & GPL code and that
CC-BY-SA 4.0 was created to address this.
Overall, it looks very tricky to comply with CC-BY-SA licensing given that there is so much LGPL and GPL code that will likely be linked into a given Arduino project that might also use this library.
Would you consider modifying your license to CC-BY-SA 4.0 or LGPL or GPL ?
If the goal is to ensure that the source always remains open source then GPL v3 will ensure that.

Here is more on the subject.
In terms of mixing s/w with different licenses,
there appears to be license compatibility issues when trying to mix CC BY-SA code
with LGPL or GPL code.

From these links:
https://creativecommons.org/compatiblelicenses/
https://wiki.creativecommons.org/wiki/ShareAlike_compatibility:_GPLv3
https://wiki.creativecommons.org/wiki/ShareAlike_compatibility_process_and_criteria

It appears that CC BY-SA 3.0 is only compatible with itself and cannot be used/linked
with LGPL or GPL code.
CC BY-SA 4.0 was created to allow merging & linking CC BY-SA code with LGPL/GPL code and in particular GPLv3.
However, if BY-SA 4.0 code is linked with LGPL or GPL code, the overall work is
licensed based on the other code license (LGPL or GPL).
i.e. if you compile and link CC BY-SA 4.0 code with LGPL 2.1 the entire project
(including the CC BY-SA 4.0 code) will be licensed as LGPL 2.1
i.e. the CC BY-SA 4.0 code converts to LGPL 2.1 for that project.
Likewise when linked against GPLv3, it becomes GPLv3 code.
Essentially it looks like CC BY-SA code is incompatible with LGPL & GPL code and the only way to use CC BY-SA code with LGPL/GPL code is to use CC BY-SA 4.0 and to use the one way convert clause to convert it to LGPL/GPL for the specific project at which point the code in that specific project is no longer CC BY-SA 4.0 and so any improvements/derivatives made to that code by someone else within that project are now LGPL/GPL and cannot go back into the original CC BY-SA 4.0 version of the code.

The person is free to contribute the changes back to the CC BY-SA 4.0 code parent instead to put the changes back into the CC BY-SA code, but it is not a requirement.

Overall, it looks like CC BY-SA licensing is very difficult to work with for s/w, and in particular for s/w that is linking against LGPL and/or GPL code.

In other words, it looks to me like CC BY-SA is a license that was intended for standalone "blobs" that do not incorporate other components, and in particular components that have a different license.
In the case of s/w library, that isn't the case.

i2c scanner example

would be great to have

Library does not compile.

See #11

(just to reopen the issue)

Is this library compatible with ARM-based boards or/and Atmega32u4-based boards?

Thanks

Reading from I2C

Does read work as well? What is the maximum transmission speed that can be achieved?

read issue

I tried to use this library with BME280 from bosch using Arduino Mini and has errors if you read more that 1 byte. For 1 byte read is working fine.

beginTransmission(bmeI2CAddress);
write(0x8E); // Pressure calibration register 2 bytes to read
endTransmission();
requestFrom(bmeI2CAddress, 2);
byte p0 = read();
byte p1 = read();

Here is result of p0 and p1 using arduino Wire
0xDC 0x94

Here is result of p0 and p1 using I2Cmaster
0xDC 0xFF

I noticed that everything that is read after first read() I got FF .
I tried also with readLast() but same faulty data I got.

Any workaround is really appreciated.

Could you ask for inclusion of this library in official Arduino's Library Manager?

This would give more visibility to your job.
Thanks

Redundant set pin in i2c_repstart

In SoftI2CMaster::i2c_repstart there is a call of "i2c_scl_hi" (line 253) followed by "i2c_scl_lo" (line 255) without any delay. So, just for clarification I guess the first call is redundant?

Library does not compile

Last version of the library does not compile ( even the example files ) in Arduino versions 1.6.8 & 1.6.9 & 1.6.10 on Linux with following error messages:

ass_i2c_wait_scl_high' referenced in section.text' of /tmp/ccgkvNNs.ltrans0.ltrans.o: defined in discarded section .text' of sketch/BMA020Soft.ino.cpp.o (symbol from plugin) ass_i2c_delay_half' referenced in section .text' of /tmp/ccgkvNNs.ltrans0.ltrans.o: defined in discarded section.text' of sketch/BMA020Soft.ino.cpp.o (symbol from plugin)
ass_i2c_delay_half' referenced in section.text' of /tmp/ccgkvNNs.ltrans0.ltrans.o: defined in discarded section .text' of sketch/BMA020Soft.ino.cpp.o (symbol from plugin) ass_i2c_delay_half' referenced in section .text' of /tmp/ccgkvNNs.ltrans0.ltrans.o: defined in discarded section.text' of sketch/BMA020Soft.ino.cpp.o (symbol from plugin)
ass_i2c_delay_half' referenced in section.text' of /tmp/ccgkvNNs.ltrans0.ltrans.o: defined in discarded section .text' of sketch/BMA020Soft.ino.cpp.o (symbol from plugin) ass_i2c_wait_scl_high' referenced in section .text' of /tmp/ccgkvNNs.ltrans0.ltrans.o: defined in discarded section.text' of sketch/BMA020Soft.ino.cpp.o (symbol from plugin)
ass_i2c_delay_half' referenced in section.text' of /tmp/ccgkvNNs.ltrans0.ltrans.o: defined in discarded section .text' of sketch/BMA020Soft.ino.cpp.o (symbol from plugin) ass_i2c_delay_half' referenced in section .text' of /tmp/ccgkvNNs.ltrans0.ltrans.o: defined in discarded section.text' of sketch/BMA020Soft.ino.cpp.o (symbol from plugin)
ass_i2c_delay_half' referenced in section.text' of /tmp/ccgkvNNs.ltrans0.ltrans.o: defined in discarded section .text' of sketch/BMA020Soft.ino.cpp.o (symbol from plugin) ass_i2c_wait_scl_high' referenced in section .text' of /tmp/ccgkvNNs.ltrans0.ltrans.o: defined in discarded section.text' of sketch/BMA020Soft.ino.cpp.o (symbol from plugin)
ass_i2c_delay_half' referenced in section.text' of /tmp/ccgkvNNs.ltrans0.ltrans.o: defined in discarded section .text' of sketch/BMA020Soft.ino.cpp.o (symbol from plugin) ass_i2c_wait_scl_high' referenced in section .text' of /tmp/ccgkvNNs.ltrans0.ltrans.o: defined in discarded section.text' of sketch/BMA020Soft.ino.cpp.o (symbol from plugin)
ass_i2c_delay_half' referenced in section.text' of /tmp/ccgkvNNs.ltrans0.ltrans.o: defined in discarded section .text' of sketch/BMA020Soft.ino.cpp.o (symbol from plugin) ass_i2c_delay_half' referenced in section .text' of /tmp/ccgkvNNs.ltrans0.ltrans.o: defined in discarded section.text' of sketch/BMA020Soft.ino.cpp.o (symbol from plugin)
ass_i2c_wait_scl_high' referenced in section.text' of /tmp/ccgkvNNs.ltrans0.ltrans.o: defined in discarded section .text' of sketch/BMA020Soft.ino.cpp.o (symbol from plugin) ass_i2c_delay_half' referenced in section .text' of /tmp/ccgkvNNs.ltrans0.ltrans.o: defined in discarded section.text' of sketch/BMA020Soft.ino.cpp.o (symbol from plugin)
ass_i2c_delay_half' referenced in section.text' of /tmp/ccgkvNNs.ltrans0.ltrans.o: defined in discarded section .text' of sketch/BMA020Soft.ino.cpp.o (symbol from plugin) ass_i2c_wait_scl_high' referenced in section .text' of /tmp/ccgkvNNs.ltrans0.ltrans.o: defined in discarded section.text' of sketch/BMA020Soft.ino.cpp.o (symbol from plugin)
ass_i2c_delay_half' referenced in section.text' of /tmp/ccgkvNNs.ltrans0.ltrans.o: defined in discarded section .text' of sketch/BMA020Soft.ino.cpp.o (symbol from plugin) ass_i2c_delay_half' referenced in section .text' of /tmp/ccgkvNNs.ltrans0.ltrans.o: defined in discarded section.text' of sketch/BMA020Soft.ino.cpp.o (symbol from plugin)
ass_i2c_delay_half' referenced in section.text' of /tmp/ccgkvNNs.ltrans0.ltrans.o: defined in discarded section .text' of sketch/BMA020Soft.ino.cpp.o (symbol from plugin) ass_i2c_wait_scl_high' referenced in section .text' of /tmp/ccgkvNNs.ltrans0.ltrans.o: defined in discarded section.text' of sketch/BMA020Soft.ino.cpp.o (symbol from plugin)
ass_i2c_delay_half' referenced in section.text' of /tmp/ccgkvNNs.ltrans0.ltrans.o: defined in discarded section `.text' of sketch/BMA020Soft.ino.cpp.o (symbol from plugin)
collect2: error: ld returned 1 exit status
exit status 1
Error compiling for board Arduino/Genuino Uno.

Include bit bang support to New LiquidCrystal library

Hi,

I am looking to support this library with all the flavours of driving LCDs that is currently supported in the New LiquidCrystal library: https://bitbucket.org/fmalpartida/new-liquidcrystal/wiki/Home

I am currently supporting it and requesting users to download from here. I was hoping that I could integrate it as part of the distribution of the New LiquidCrystal library but I haven't found the licensing terms of your source code. The distribution would be with your files completely untouched and indeed mention its usage and link to this repo in its wiki.

Please share your thoughts.

Best regards,

fm

i2c_stop seems not to meet 'i2c stop' condition.

Hi, tod!
I'm Kenny Kim from South Korea.

I found a case that SDA is still high before call of the i2c_stop().
In that case, the i2c stop condition does not meet, and any further commands after endTransmission() don't work. To meet the STOP condition: SDA should be low before doing stop.

Need to insert i2c_sda_lo() into the i2c_stop() function like this:

268 // Send a STOP Condition
269 //
270 void SoftI2CMaster::i2c_stop(void)
271 {
272 // To meet the STOP condition: SDA should be low before doing stop.
273 i2c_sda_lo(); // makes sda low surely.
274 i2c_scl_hi();
275 _delay_us(i2cbitdelay);
276

277 i2c_sda_hi();
278 _delay_us(i2cbitdelay);
279 }

Thank you!