I was running out of program memory on a 16F84 the other day, and looked
at the line card for possible replacements. EPROM would still be OK, so I
picked the 16CE625. It says, 2k-words program memory, 128 bytes data EEPROM.
Sounds fine. So, I ordered a 16CE625JW for testing. When I got it today,
I stared at it in disbelief for some minutes (really!), it had two chips
inside the case, and was actually labeled 16C625 /JW 9842HAR , note the
'C' not 'CE'... Hmm. This led me to actually look at the datasheet, while
still (foolishly, it seems so now) believing that the EEPROM would be
accessed much like in the 16C84 or 16F84.
And sure enough, you can imagine my disappointment when I saw the reference
to "EEPROM Peripheral Operation", bi-directional 2-wire bus, etc... HEY!!
It's just an on-chip (or, in this case, in the same case, but not on chip)
I2C bus EEPROM. Sigh... Okay, the difference to having a separate EEPROM
is two saved I/O but that wouldn't have been a problem anyway; the price
difference is about the same as buying a 16C622 and sticking a separate
I2C EEPROM next to it.
Next I checked 12CE518/9, and 12CE673/4 - they were the same internal I2C
stuff. Give me a break... Only the 16F877 seems to act like 16F84, but it's
too big (and expensive) for this application. So I guess I'm now stuck
with it :(
Dr. Imre Bartfai
I understand your disappointment, but I think, it is not so bad as it
seems to be. I wrote the appropriate routines for myself and I could
handle that on-board EEPROM w/o any problems. The s/w overhead is moderate
(approx. 100 words or so). And the circuit is simpler than to get a
separate external I2C module.
I hope this comfort you.
More... (looser matching)
- Last day of these posts
- In 1999
, 2000 only
- New search...