[Coco] serial port problems on coco2

[chris]

No dice :(

All I get is 1's. The number does not flip with pin 2 going high or low.





On Jul 28, 2012, at 2:25 PM, Aaron Banerjee wrote:

> Hmmm.  I'm not sure if this has been answered (e-mail glitch), but...
>
> Try checking bit 0 of &HFF22 while changing the voltage of your  
> "status" line (RS232IN - pin 2).  E.g.
>
> 5  PRINT PEEK(&HFF22)
> 10 GOTO 5
>
> and then change the voltage on pin 2 of the RS232.  The number you  
> get should change (e.g. from an even to odd number) based on the  
> voltage.  If it doesn't, there's something wrong.  My first guess  
> would be either the PIA (6821) (U2 on a Coco 2, located on the  
> "left" {away from cartridge connector} side of the board) or the  
> SALT chip (U1 - located nearby the big power transistor).
>
>             - Aaron
>
>
> On Jul 27, 2012, at 6:26 PM, chris wrote:
>
>> Hello list,
>>
>> Im having a problem with my main coco2 now.
>>
>> When I try and print anything the machine just hangs until I hit  
>> the reset. llist also makes it hang.
>>
>> I verified that the "printer ready" high voltage is making it in to  
>> the machine by testing it right on the back of the port inside the  
>> computer. I hook the printer up to my 16K coco2 and it prints fine.
>>
>> Could this be a problem with one of the PIA's?
>>
>>
>> Thanks
>>
>> -chris
>>
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>
>
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