Tri state input/output chip

[treitmey]

I am looking for a chip I can put on port d. I would like it to be in transparent mode or tri-state mode. The problem is I want different pins on port be to input and output,... set_tris_d(0b10011010).

Which chip can do both input and output in transparent mode. then switch to tri-stated. I was thinking 74HC573. Can this work in both input and output at the same time?

[Steve H.]

Tri state is really just input mode where you don't read the input, right? For port expansion I have used the Maxim MAX7301, it is an SPI device with pretty good drive levels. Fully programmable for bi-directional I/O.

Philips also makes a I2C device, but as I recall it only has week pullup on output not a true push/pull drive.

Regards,

Steve Hageman

[treitmey]

No. When I say tristate, I want say 8 of these on the port D and then use a 3-8 de-mux to pick the device. so 1 device is active and the rest are tristated.

Good idea the max7301, but I think that may be too slow.
I'll get a sample and experiment.

I think the closest is the 74HC245 transciever.
BUT that is all in or all out. NOT A MIX

[PCM programmer]

[treitmey]

I would like fast IO to say, my keypad, my lcd, my relays, my dip addresses, my wiegand reader(4 readers) ... I run out of pins fast,.. so perhaps the solution is a bigger uP.

[Mark]

Bigger pic or have you thought about using another pic to do what you want.

[treitmey]

yes, I thought about that, not the cleanest, tho...
I'll use this as an excuse to get a bigger chip and lean something new.

(really thought the 18F452 would hold me for a while)

[diogoc]

I want use max7301 with spi interface. someone have some code example?

thanks