stephane/modbusino — pull request #3 by karlp (2011-10-20 12:30:15+00:00)
Title: make modbusino 56% moah awesome.

Fixes/tweaks/changes included:
* fix flushing. This is probably the most important. Earlier, the timing would often mean that uart.isAvailable() would sometimes fail, purely because it was between bytes. It needs to properly wait for a genuine clear space.
* support a tx enable pin, necessary for many rs485 transceiver chips
* support setting the slave id later, if for instance, you generate the slave id from a EUI48 chip, or similar
* support logical addressing (td: registers at base address 0x4000, rather than at 0)
* properly ignore packets not addressed to us
* more return codes for the various conditions
* added example compatible with the jpzomenta code
* added example showing usage of 485 transceiver and logical addressing

Reasons for being so slow to submit this: had to remove some timings specific to an internal part being used here :)