Steve,

This isn't the first time you have been caught defending the i8255!

I think this chip is not a good choice for high volume product placement. That said, i think it is just fine for "one of a kind" or even a "swiss army knife" cpu pcb.

You just have to be aware of it's warts.

It is slow, you have to delay between consecutive writes to the device. The 5 MHz device shortens this time. Writes to the control reg momentarily glitches the ports.
Chuck Peddle (Mr. 6502) made lot's of noise about this when he designed the Moto PIA and later his VIA (which do not glitch).

I find i have never yet used the agility of the port definition in real time instead i would set it at "init time" and leave it in state. 1 momentary glitch never impacted that which i was doing. (keyboards, LEDs, DACs, etc).

I have observed however that i often thought that if i were to do a device again that i would just use latches or buffers to achieve the needed functionality.

a ref:

HDL 8255

regards,
p