Philips PFC8584 or PIC 16F87

William At MyBlueRoom

New Member

• Aug 9, 2006

• #1

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
?

 

K

kjennejohn

New Member

• Aug 9, 2006

• #2

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

New Member

• Aug 10, 2006

• #3

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

Super Moderator

Most Helpful Member

• Aug 10, 2006

• #4

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

 

Mike - K8LH

Well-Known Member

• Aug 10, 2006

• #5

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

New Member

• Aug 11, 2006

• #6

Nigel Goodwin said:

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

Click to expand...

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

 

Nigel Goodwin

Super Moderator

Most Helpful Member

• Aug 11, 2006

• #7

William At MyBlueRoom said:

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

Click to expand...

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

New Member

• Aug 11, 2006

• #8

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

Well-Known Member

• Aug 11, 2006

• #9

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