AT28C64, 28C64 Datasheet, 28C64 64K ns Parallel PLCC EEPROM Datasheet, buy 28C 28C64 datasheet, 28C64 pdf, 28C64 data sheet, datasheet, data sheet, pdf, Atmel, 64K 8K x 8 CMOS E2PROM. 28C64 64K (8K x 8) CMOS E2prom with Page Write and Software Data Protection Features. Fast Read Access Time ns Automatic Page Write Operation.
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Thanks for the info. 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.
One thing that is missing is on page 7 of the datasheet, it states that you need to write a sequence 28f64 codes to disable write-protection. PeterJ 16k 20 42 Initializing pins for write I don’t really like the design, but my guess is that it was trying to be compatible with an earlier part where one could write locations one at a time and just wait after each one.
Sign up or log in Sign up using Google. Datasheef chips are new, and I actually have two from two different manufacturers. Post as a guest Name. I have edited my question. Here is the serial output.
(Datasheet) 28C64 pdf – 64K EEPROM (1-page)
Mar 26 ’13 at Since I am only using the first three address pins, the rest are tied low. I understand the benefits of separating the code into subroutines and will probably do this, but for now I am just trying to get the byte write working.
Any help would be much appreciated. All behave the same. I’d recommend following that same sequence and also change your write sequence to follow the diagram on the following page.
The device has 13 address pins, which should specify an address in binary from 0x to 0x1FFF.
Thanks for the response, supercat. Looking at the datasheet on page 12 it shows a timing diagram and Chip Enable Access Time can be up to nS. 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.
I wrote a program for the Arduino Uno that writes data to the first 4 addresses and then reads the data back. When the timer expires, an internal write cycle is triggered and additional writes before it completes. You have not indicated that you are doing anything with them?
The same diagram shows CE being asserted followed by OE for a read cycle. Mar 27 ’13 at Email Required, but never shown. Here is my code, sorry if it seems too cluttered: Here is my code, sorry if it seems too cluttered:.
28C64A-15 – 28C64A 64K 150ns Parallel EEPROM Technical Data
If it has, you’ll need to wire up all your address wires datashret order to disable it. Sign up using Facebook. I am using the Xicor 28C64AP chip datasheet. I have tested an earlier version of the above program with a static RAM chip and everything works great. I added ms delays between every control pin change and made sure the order was consistent with the datasheet, but still no luck.
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 have tied the top 10 address bits low and am only using the first 3 for now. Home Questions Tags Users Unanswered.