M95128-W EEPROM. First byte of each page not writing or reading correctly

[Daniel Beyzade]

Posted on February 21, 2017 at 22:48

I am working on a library for controlling the

http://www.st.com/content/ccc/resource/technical/document/datasheet/11/47/cf/4a/88/23/42/87/CD000014pdf/files/CD000014pdf/jcr:content/translations/en.CD000014pdf

from an STM32 device. I have the library writing and reading back data however the first byte of each page it not as expected and seems to be fixed at

0x04

.

For example I write 128 bytes across two pages starting at

0x00

address with value

0x80

. When read back I get:

byte[0] = 0x04;
byte[1] = 0x80;
byte[2] = 0x80;
byte[3] = 0x80;
.......
byte[64] = 0x04;
byte[65] = 0x80;
byte[66] = 0x80;
byte[67] = 0x80;

I have debugged the SPI with a logic analyzer and confirmed the correct bytes are being sent. When using the logic analyzer on the read command the mysterios

0x04

is transmitted from the EEPROM.

Here is my code:

void FLA::write(constvoid* data,unsignedint dataLength,uint16_t address)

{ int pagePos =0; int pageCount =(dataLength +64-1)/64; int bytePos =0;int startAddress = address; while(pagePos < pageCount) { HAL_GPIO_WritePin(GPIOB,GPIO_PIN_2, GPIO_PIN_SET); // WP High chipSelect(); _spi->transfer(INSTRUCTION_WREN); chipUnselect(); uint8_t status = readRegister(INSTRUCTION_RDSR); chipSelect(); _spi->transfer(INSTRUCTION_WRITE); uint8_t xlow = address &0xff; uint8_t xhigh =(address >>8); _spi->transfer(xhigh);// part 1 address MSB _spi->transfer(xlow);// part 2 address LSB for(unsignedint i =0; i <64&& bytePos < dataLength; i++) { uint8_t byte =((uint8_t*)data)[bytePos]; _spi->transfer(byte); printConsole(''Wrote byte to ''); printConsoleInt(startAddress + bytePos); printConsole(''with value ''); printConsoleInt(byte); printConsole(''\n''); bytePos ++; } _spi->transfer(INSTRUCTION_WRDI); chipUnselect(); HAL_GPIO_WritePin(GPIOB,GPIO_PIN_2, GPIO_PIN_RESET); //WP LOW bool writeComplete =false; while(writeComplete ==false) { uint8_t status = readRegister(INSTRUCTION_RDSR); if(status&1<<0) { printConsole(''Waiting for write to complete....\n''); } else { writeComplete =true; printConsole(''Write complete to page ''); printConsoleInt(pagePos); printConsole(''@ address ''); printConsoleInt(bytePos); printConsole(''\n''); } } pagePos++; address = address +64; } printConsole(''Finished writing all pages total bytes ''); printConsoleInt(bytePos); printConsole(''\n''); } void FLA::read(char* returndata,unsignedint dataLength,uint16_t address) { chipSelect(); _spi->transfer(INSTRUCTION_READ); uint8_t xlow = address &0xff; uint8_t xhigh =(address >>8); _spi->transfer(xhigh);// part 1 address _spi->transfer(xlow);// part 2 address for(unsignedint i =0; i < dataLength; i++) { returndata[i]= _spi->transfer(0x00); } chipUnselect(); }

Additionally I have tried writing sequentially 255 bytes increasing data to check for rollover. The results are as follows:

byte[0] = 4; // Incorrect Mystery Byte 
byte[1] = 1; byte[2] = 2;
byte[3] = 3; 
....... 
byte[63] = 63; 
byte[64] = 4; // Incorrect Mystery Byte 
byte[65] = 65; 
byte[66] = 66;
....... 
byte[127] = 127; 
byte[128] = 4; // Incorrect Mystery Byte 
byte[129} = 129;

Pattern continues. I have also tried writing just 8 bytes from address 0x00 and the same problem persists so I think we can rule out rollover.

I have tried removing the debug printConsole and it has had no effect.

Here is a SPI logic trace of the write command:

And a close up of the first byte that is not working correctly:

Code can be viewed on gitlab here:

https://gitlab.com/DanielBeyzade/stm32f107vc-home-control-master/blob/master/Src/flash.cpp

Init code of SPI can be seen here in MX_SPI_Init()

https://gitlab.com/DanielBeyzade/stm32f107vc-home-control-master/blob/master/Src/main.cpp

I have another device on the SPI bus (RFM69HW RF Module) which works as expected sending and receiving data.

Any suggestion or help appreciated.

Daniel

#spi-stm32-flash-eeprom #m95128

[Tesla DeLorean]

Posted on February 22, 2017 at 17:18

Show the chip select in the context of the signals being diagrammed here