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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One thing that is missing is on page 7 of the datasheet, it states that you need to write a sequence of codes to disable write-protection.
Sign up using Email datasheeet Password. I’d recommend following that same sequence and also change your write sequence to follow the diagram on the following page.
I added ms delays between every control pin change and made sure the order was consistent with the datasheet, but still no luck. I am using the Xicor 28C64AP chip datasheet.
Post as a guest Name. Thanks for the response, supercat. I have tested an earlier version of the above program with a static RAM 28c46 and everything works great.
Since I am only using the first three address pins, the rest are tied low. I wrote a program for the Arduino Uno that writes data to the first 4 addresses and then reads the data back. The device has 13 address pins, which should specify an address in binary from 0x to 0x1FFF.
I have edited my question. If it has, datasgeet need to wire up all your address wires in order to disable it. Sign up or log in Sign up using Google.
I have tied the top 10 address bits low and am only using the first 3 for now. That might help things. That will make the remainder of your code much more readable. I datsheet the benefits of separating the code into subroutines and will probably do this, but for now I am just datashewt to get the byte 28c664 working. BTW, if the chips are equipment pulls as opposed to new parts, it’s possible that the “software protection” feature has previously been enabled.
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 Dataseet 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 vatasheet OE, samples all the data wires, and releases CE and OE.
PeterJ 16k 20 42 When the timer expires, an internal write cycle is triggered and additional writes before it completes. Here is the serial output.
Looking at the datasheet on page 12 it shows a timing diagram and Chip Enable Access Time 286c4 be up to nS. Home Questions Tags Users Unanswered. Thanks for the info. All behave the same. Mar 27 ’13 at Initializing pins for write 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.
Any help would be much appreciated. Sign up using Facebook.