Expanding I/O Pins
jkroylance
Posts: 12
I'm planning on using a propeller chip as the processor for a digital instrument panel I'm designing for my car and I need a way to control 392 LEDs with minimal I/O pins. I've seen 24-port I/O expanders on eBay but can't figure out what chip they're using. Any advice would be greatly appreciated.
Comments
The 74HC595 is an 8 bit output expander that's cascadable, needs 4 I/O pins, but several can be shared among several strings of them. TI makes a similar chip that includes MOSFET drivers on chip.
my 2 cents
Why not use the I2C bus if high speed is not really an issue..
You could use the 2 lines that connect to the eeprom (24LC256) ..
Mike G suggested the MPC23017 that is a good one also consider looking at http://www.nxp.com/pip/PCA9635_2.html
Or start at http://nxp.com and search thru the I2C devices.
It is amazing what chips these people make for the I2C bus..
Ronald Nollet
Parallax Australia Distributor