Re: Strange 8255 behavior

From: Gerrit Heitsch <*gerrit_at_laosinh.s.bawue.de*> Date: Sat, 16 Jun 2018 08:03:23 +0200 Message-ID: <2d7f60c9-3aef-aac1-39ce-9d08f4718e3f@laosinh.s.bawue.de> · gerrit_at_laosinh.s.bawue.de

On 06/16/2018 07:29 AM, Jim Brain wrote:
> If NMOS drives hard to ground and not very hard to +5V, you *might* be 
> able to get by with letting the pins float high via 1K resistors and 
> drive only to ground with the CPLD (Xilinx has tristate output buffer 
> options, and I am sure the rest do as well)

Unfortunatly, that would increase power consumption by quite a bit. 16 
I/O with 1 KOhm set to LOW would be 80 mA just for the I/O.

  Gerrit