Behaviour was changed from stack to queue in
8977c7eb58, and this updates variable names
to match. Also updates other references (docs, error messages).
This allows to efficiently send to an I2C slave data that is made up of
more than one buffer. Instead of needing to allocate temporary memory to
combine buffers together this new method allows to pass in a tuple or list
of buffers. The name is based on the POSIX function writev() which has
similar intentions and signature.
The reasons for taking this approach (compared to having an interface with
separate start/write/stop methods) are:
- It's a backwards compatible extension.
- It's convenient for the user.
- It's efficient because there is only one Python call, then the C code can
do everything in one go.
- It's efficient on the I2C bus because the implementation can do
everything in one go without pauses between blocks of bytes.
- It should be possible to implement this extension in all ports, for
hardware and software I2C.
Further discussion is found in issue #3482, PR #4020 and PR #4763.
It's more common to need non-blocking behaviour when reading from a UART,
rather than having a large timeout like 1000ms (the original behaviour).
With a large timeout it's 1) likely that the function will read forever if
characters keep trickling it; or 2) the function will unnecessarily wait
when characters come sporadically, eg at a REPL prompt.
Damien George
Jim Mussared
Paul m. p. P
Peter Hinch
Vicki Lowe
Tom McDermott
Arsenijs
Nicko van Someren
Mike Causer
Yonatan Goldschmidt