Look-up tables were used for determining the delay loop counts before.
Based on these hand-tuned values, the loop overhead was estimated for
each option -- 80 and 160 MHz, fast and slow GPIO access. Instead of the
great number of tunable parameters one now only has to tune the overhead
values if the code is changed.
Functions were added to the API which allow setting an arbitrary
frequency. API backward compatibility is retained.
i2c: fix potential overflow situation
* custom delay
* Update comment
* add bus control status, add some missing include & fixed display output on sh1104 (#319)
* add some missing include
* Fixed display on SH1106
* Fix comment, add force sytem, rework flag, 16 bits data transfert
* Update all library with new I2C API
* custom delay
* Update comment, add bus control status
* fix i2c read + fix ds3231 temp + fix ssd1306 send
Configure the pins as open-drain just in case the code forces them
high although it should be configuring them as inputs to let them float high.
Initialize the pins when the driver is initialized.
Enable the internal pull-ups to prevent them floating too high if not
connected and damaging the circuit.
Fixed reference to unknown environment var
Moved drivers into extras folder and added additional documentations.
Changed LOCAL to static and renamed DEBUG to BMP180_DEBUG
