Hi folks,
I was working on programming I2C on a 28X when I had a problem.
Testing the SCL (pin c3) showed that it wasn't changing.
I then ran a quick programmed basic output check, monitoring the port with LED's on each pin.
This revealed that pins c2 and c3 were not responding to "high portc pin" commands.
I found that if pinsc = %11111111 is invoked, all outputs do activate.
Thinking that it may be a case of a damaged chip, I tried two more brand new 28X's on my proto board and discovered that they behaved exactly the same!
So, I checked the datasheet for the IC (16F873) thinking there may be something different about those two pins, but found nothing.
There was a note re being carefull when using Trisc register because of possible interaction of any peripheral control, which can over-ride the Trisc setting.
Of course, in the case of a Picaxe, this would only refer to controls implemented by the bootstrap program (I assume).
Anyway, it is time to ask the Forum for any ideas/answers.
kenmac
I was working on programming I2C on a 28X when I had a problem.
Testing the SCL (pin c3) showed that it wasn't changing.
I then ran a quick programmed basic output check, monitoring the port with LED's on each pin.
This revealed that pins c2 and c3 were not responding to "high portc pin" commands.
I found that if pinsc = %11111111 is invoked, all outputs do activate.
Thinking that it may be a case of a damaged chip, I tried two more brand new 28X's on my proto board and discovered that they behaved exactly the same!
So, I checked the datasheet for the IC (16F873) thinking there may be something different about those two pins, but found nothing.
There was a note re being carefull when using Trisc register because of possible interaction of any peripheral control, which can over-ride the Trisc setting.
Of course, in the case of a Picaxe, this would only refer to controls implemented by the bootstrap program (I assume).
Anyway, it is time to ask the Forum for any ideas/answers.
kenmac