Re: gEDA-user: furnace controller II: I/O driver

[DJ Delorie <dj@xxxxxxxxxxx>]

> Is using the two pins to create an I2C port an option?

Well, I need to signal fast enough (and with sufficiently reliable
timing) to drive the 1wire bus.  Besides, it's not a lack of pins
that's the problem (I can switch to the 144 pin version and gain 44
GPIO pins), it's the flexibility and EMI concerns.

Plus, the "output" pins[*] happen to be tied to the four UART TxDs
inside the m32c, and the "input" pins to the RxDs, so the ports can be
used for serial as well as GPIO.

[*] For each zone, one I/O line uses TxD for output and a GPIO for
    input, and the other I/O line uses a GPIO for output and RxD for
    input.