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Clarification on M99512 EEPROM

Associate II


I hope to get clarification by the expert regarding the M99512 EEPROM - SPI connectivity. I recently had the chip together with Microchip AVR128DA64 mcu on a custom board. I found that at 500KHz communication with the eeprom, I can only store maximum 126 bytes per page, unlike mentioned by the data sheet. I have done several test as follows:

1. write 128 bytes in single write starting at index 0 of the page - result data stored only 126 bytes from index 0 to 125. Location 126 and 127 data kind of corrupted

2. Then, I write 2 bytes data in one write starting at index 126. I managed to read back the data at index 126 and 127. Infact, I can read 126 bytes of the data starting at index 2 to index 127. I found data at index 0 and 1 were corrupted.

3. similarly about reading data from multiple pages in 1 read operation. I managed to read maximum 252 bytes of data from only 2 pages, provided that at page 0, I stored data starting at index 2 until index 127 (126 bytes) and at page 1, I stored data starting from index 0 until index 125 (126 bytes)


I hope to get clarification on this matter and wonder if there is a way around this issue. Please help.


NOTE: To my testing, doing single write operation or multiple write per page ... will always end up with 2 corrupted data at index 1 and 2 above the last written byte. Example, writing to page 300

1. single write 20 bytes starting at index 0 to 19 with these data:


2. Then write 4 bytes of data "WWWW" starting from index 10 to index 13, the page 300 will end up with these data:


where the 2 dotted  (index 14 and 15) indicate the 2 corrupted data


Thank you,

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