[hpsdr] hpsdr Digest, Vol 1, Issue 22

[Greg Overkamp]

> 
> There might be a problem with I2C on the FPGA, has
> anyone actually 
> implemented it? SPI is quite easy, on the other
> hand.
> 
> Leon 
> 
> ---

I have used the Opencores I2C master in two projects.
It works great and is well documented. In both cases,
I ripped out the Wishbone bus interface. In one
project the I2C master was controlled by a state
machine, and in the other project it was connected to
a CPU bus inside the FPGA.

I feel that I2C is easier to use (hang chips off of)
than SPI. SPI requires clock, data, and chip select. I
have even seen SPI LCD controllers that require a
fourth data/command strobe. I2C is only two wires, and
each new slave device just "clips" onto the bus. The
multiple master design of the bus is very clever, and
makes it easy to hang two masters on the bus, for
example one I2C master in an FPGA and one in a
microcontroller.

Greg
WD9DEX








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