Changing a normally input pin to an output.

Gramps

Senior Member
How to change C.3 on the 08M2 chip to an output. I'm sure we saw the command in the getting started manual.
Please jog my memory with a page number.
Thanks, Gramps
 

lbenson

Senior Member
How to change C.3 on the 08M2 chip to an output. I'm sure we saw the command in the getting started manual.
There is no command to do this and as the post linked to by Bear indicates, you need external hardware to be able to do anything very useful with it. Time to step up to a 14M2 perhaps.
 

inglewoodpete

Senior Member
The 08M2's pin C.3 is the base PIC's master reset and Vpp pin. As a result, it can never be configured as an output, although some members have demonstrated how the weak pullup can be used to make it perform as an output when used with other additional components. The trouble with that solution is that you have to add three components which involves 7 additional component leads - one more than replacing the 08M2 with a 14M2! Go for the 14M2 and you get 6 additional I/O pins and more memory.
 

erco

Senior Member
I'm in the middle of a project and having excellent results using an 08m2's C.3 pin with a 2N7000 mosfet to provide Picaxe auto-off power control using the PULLUP command. Not a full soft on/off switch, but very useful.

Edit: Project finished, details & video at https://picaxeforum.co.uk/threads/08m2-christmas-gift.32233/ I used a 1M pulldown on the 2N7000 gate per bear's prior post, easily overpowered by the software-controlled PULLUP on C.3, which is ~35K per https://picaxeforum.co.uk/threads/internal-pullup-resistors.25916/
 
Last edited:

westaust55

Moderator
Okay I found it.
Called reverse command
And Pin Three on an 08M2 is exempt.
It cannot be reversed!


😥
Albeit that Gramps’ message is 5months old, for some completeness,
The OUTPUT command will also change pin to be an output
within the limits of the hardware/silicon so again C.3 on the 8 pin devices is excluded.
 
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