ZX40n Port A

[FFMan]

Is there any unusual about port A on a ZX40N that would cause it to not reflect putpin commands properly ?

I'm building a Nixie based time and temp display. I'm using port b to drive 4 tubes (4 x anodes, 4 x BCD) and now trying to add port A to drive the same for time display.

I can't get port A to put the pins high. I've tried 2 different processors, and written simple test program with just the pin assignments but I can't seem to get port A to behave.

Anything unusual here ?

[dkinzer]

Is there any unusual about port A on a ZX40N that would cause it to not reflect putpin commands properly ?

Do you have both Vcc pins connected to the power supply? Also, external circuitry can prevent a pin from going high when it should. You might try your experiment with nothing connected to the pins.

Also, you might try manipulating the port directly using Register.DDRA and Register.PORTA. If that works then it is an issue with PutPin().

[FFMan]

I only have VCC connected 5v.

Should i also connect AVCC and/or AREF (I guess that's only for ADC ?)

Been a while since I used a zx40n

[dkinzer]

Should i also connect AVCC and/or AREF (I guess that's only for ADC ?)

AVcc, yes. ARef not needed unless using the ADC. From the datasheet:

AVcc is the supply voltage pin for Port A and the Analog-to-Digital Converter. It should be externally connected to Vcc even if the ADC is not used.

All AVR devices have this in common.

[FFMan]

thanks don - that sorted the issue.

i should read the 'Required external components' list more often !