Use of empty space in Prizm

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Re: Use of empty space in Prizm

Postby SimonLothar » Wed Mar 06, 2013 7:05 am

Arkhs wrote:I was thinking about removing the db9 connector and soldering a 3pin female (connected to Rx, Tx and Gnd).
I think you have to remove the MAX233, too. Otherwise the MAX233's TTL-IO-lines would compete against the calculator's.

Arkhs wrote:...because it needs 3,3V (and it is also very large).
The TTL-specifications are: low:<=0.8V and high:>=2V.
As the PIC can be interfaced by a MAX233, its signal levels are obviously TTL.
2.8V and 3.3V should make no difference concerning the signal-level.
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Re: Use of empty space in Prizm

Postby Arkhs » Thu Mar 07, 2013 11:29 pm

Thanks for the info.


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