Greg Solberg <greg@MIGSOL.COM> wrote:

>I'm implementing an I2C interface to an 24LC01 EEPROM.  I had, of
>course, planned to use the built in I2C ports of the '73.  After
>reading the data sheet and a few Microchip App. notes, it seems that
>all the fancy I2C hardware in the '73 is only usefull for slave mode.
>As far as I can tell, I have to push all the bits out in software, and
>I gain nothing by using the I2C ports over any other port for Master
>Mode.
>
>Is this true or am I missing something?

Greg:

It's true... The Microchip databook boasts of "support in hardware to
facilitate software implementations of the master functions", but for
single-master mode, this so-called "support" amounts to nothing more
than forcing two bits in the PORTB output latch low.  This saves a
whopping two BCF instructions, but requires an extra pullup resistor...
Not exactly a fair trade.

It this point, I'm tempted to ask the following question:

    Given that Microchip wants to become a leading supplier of I2C
    EEPROMs, doesn't the lack of hardware support for communication
    between those EEPROMs and Microchip's only other products (the PIC
    microcontrollers) seem sort of stupid?

However, I'll refrain... My local FAE is busy enough without having to
field angry phone calls from Microchip's list-monitors.

-Andy

--
Andrew Warren - fastfwd@ix.netcom.com
Fast Forward Engineering, Vista, California