Philips PFC8584 or PIC 16F87

[William At MyBlueRoom]

For use as a slave i2c device... Controlling 8 relays or 8 switches or a combination of both.

Pros & Cons of...
Philips PFC8584 or PIC 16F87
?

 

[kjennejohn]

Consider this IC also...

Microchip makes the MCP23016, which is a 'slaved' processor that uses I2C to talk to a 'master' processor. The page below supplies app notes and data sheets. I picked this up from another forum, where someone mentioned purchasing these at Newark Electronics.

**broken link removed**

Hope this helps some,
kenjj

 

[William At MyBlueRoom]

Great, just the part I was looking for. It's funny I love Microchips PICs but I often forget they build other chips too.

 

[Nigel Goodwin]

Is there some specific reason you want to use I2C?.

 

[Mike - K8LH]

Bill,

Did you mean a PCF8584? I'm downloading the Data Sheet now. Does it provide sinking or sourcing drivers with more than the standard 20/25-ma available from the MCP23016/'23017?

Mike

 

[William At MyBlueRoom]

Is there some specific reason you want to use I2C?.

I2C makes for a great two wire expansion bus. Easy to add I/O and the hardware is built into many PICs.

 

[Nigel Goodwin]

I2C makes for a great two wire expansion bus. Easy to add I/O and the hardware is built into many PICs.

I2C was specifically designed to simplify the PCB layout in TV sets, and has since spread to other products as well. If you have a requirement for multiple IC's connected to the same bus (or wish to use IC's that are only available as I2C), then it's a good idea - but it's not really very good as a general purpose bus, and if you're only connecting two PIC's together it's greatly over complicated for the job.

 

[William At MyBlueRoom]

It's for RTCs, EEPROMs and Relays. I'm already using the bus in the design. In another design I have to use SPI 3wire. I like them both, SPI requires CS lines but is very simple and I2C uses only 2 wires but the protocol is more complex.

 

[Mike - K8LH]

I like the 3-wire MIC5841 or MIC5821 serial-to-parallel 8-bit sinking driver chips for relays (500-ma per output and something like 30-50v).

Mike