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I understand the benefits catasheet separating the code into subroutines and will probably do this, but for now I am just trying to get the byte write working.
Thanks for the info. BTW, if the chips are equipment pulls as opposed to new parts, it’s possible that the “software protection” feature has previously been enabled. I don’t really like the design, but my guess is that it was trying to be compatible 2c64 an earlier part where one could write locations one at a time and just wait after each one.
Since I am only using the first three address pins, the rest are tied low. Email Required, but never shown. Thanks for the response, supercat. Any help would be much appreciated.
The chips are new, and I actually have two from two different manufacturers.
28C64 Datasheet PDF
Sign up using Email and Password. Mar 26 ’13 at All behave the same. Here is the serial output. PeterJ 16k 20 42 Post as a guest Name. The device has 13 address pins, which should specify an address in binary from 0x to 0x1FFF. Here is my code, sorry if it seems too cluttered: If it has, you’ll need to wire up all your address wires in order to disable it.
28C64 Datasheet(PDF) – ATMEL Corporation
Also, I would suggest that you should write a writebyte procedure which sets all address and data wires to output and puts proper values on them, ensures WE and OE are deasserted, asserts CE, asserts and release WE, and releases CE, and a readbyte procedure which sets all address wires to output and puts proper values on them, sets all data wires to input, asserts CE and OE, samples all the data wires, and releases CE and OE.
When the timer expires, an internal write cycle is triggered and additional writes before it completes.
The same diagram shows CE being asserted followed by OE for a read cycle. Sign up using Facebook. I added ms delays between every control pin change and made sure the order was consistent with the datasheet, but still no luck. That might help things.
That will make the remainder of your code much more 28f64. I have tested an earlier version of the above program with a static RAM chip and everything works great.
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I am using the Xicor 28C64AP chip datasheet. You have not indicated that you are doing anything with them?
28C64 Datasheet PDF –
I’d recommend following that same sequence and also change your write sequence to follow the diagram on the following page. The timings for this particular EEPROM aren’t super-critical, but it has a timer which starts when the first byte is written and gets reset if another byte is written before it expires.