Question
M95M04-DR EEPROM roll-over issue
I am working with the M95M04-DR eeprom. In my program, I must save logs of data inside the EEPROM memory. I wriite data in chunks of 25 bytes.
I have written 11 chunks of data ant noticed a problem. I have a function to read back multiple bytes of data :
void EEPROM_read_multiple_bytes(spi_device_handle_t spi,uint32_t start, uint32_t number,uint8_t* data_bufer){
if( (start + number) > 512000 ){
printf("EEPROM out of bounds \n");
return;
}
while(EEPROM_check_if_busy(spi) != true){ // return true if flash is not busy
vTaskDelay(10/portTICK_PERIOD_MS);
//printf("waiting for busy flag to clear \n");
}
uint32_t length = number;
spi_transaction_ext_t trans = {
.base = {
.flags = SPI_TRANS_VARIABLE_ADDR,
.cmd = 0b00000011,
.addr = (uint32_t)start,
.rxlength = length*8,
.rx_buffer = data_bufer,
},
.address_bits = 24,
};
spi_device_polling_transmit(spi, (spi_transaction_t*)&trans);
data_bufer = (uint8_t*)trans.base.rx_buffer;
}I write some sample data to my chunks, for example:
The first chunk will have 25 bytes all set 0
the second chunk will have 25 bytes all set to 1
the third chunk will have 25 bytes all set to 2 and so on...
I am able to read back chunks and the data seemed to be correct at first, but once I reach 256 address, I start to receive incorrect data.
In my main, I call the function:
uint8_t data_holder[275];
EEPROM_read_multiple_bytes(external_eeprom,25,275,data_holder);
for(int i = 0; i <250;i++){
printf("data_holder[%i]=%u \n",(25+i),data_holder[i]);
}
Please note that I ignore first 25 bytes because they are used for something else in my program. I write chunks from starting address = 25; so if I write 10 chunks it will start at 25 and end at 275.
The data in serial monitor:
data_holder[25]=0
data_holder[26]=0
data_holder[27]=0
data_holder[28]=0
data_holder[29]=0
data_holder[30]=0
data_holder[31]=0
data_holder[32]=0
data_holder[33]=0
data_holder[34]=0
data_holder[35]=0
data_holder[36]=0
data_holder[37]=0
data_holder[38]=0
data_holder[39]=0
data_holder[40]=0
data_holder[41]=0
data_holder[42]=0
data_holder[43]=0
data_holder[44]=0
data_holder[45]=0
data_holder[46]=0
data_holder[47]=0
data_holder[48]=0
data_holder[49]=0
data_holder[50]=1
data_holder[51]=1
data_holder[52]=1
data_holder[53]=1
data_holder[54]=1
data_holder[55]=1
data_holder[56]=1
data_holder[57]=1
data_holder[58]=1
data_holder[59]=1
data_holder[60]=1
data_holder[61]=1
data_holder[62]=1
data_holder[63]=1
data_holder[64]=1
data_holder[65]=1
data_holder[66]=1
data_holder[67]=1
data_holder[68]=1
data_holder[69]=1
data_holder[70]=1
data_holder[71]=1
data_holder[72]=1
data_holder[73]=1
data_holder[74]=1
data_holder[75]=2
data_holder[76]=2
data_holder[77]=2
data_holder[78]=2
data_holder[79]=2
data_holder[80]=2
data_holder[81]=2
data_holder[82]=2
data_holder[83]=2
data_holder[84]=2
data_holder[85]=2
data_holder[86]=2
data_holder[87]=2
data_holder[88]=2
data_holder[89]=2
data_holder[90]=2
data_holder[91]=2
data_holder[92]=2
data_holder[93]=2
data_holder[94]=2
data_holder[95]=2
data_holder[96]=2
data_holder[97]=2
data_holder[98]=2
data_holder[99]=2
data_holder[100]=3
data_holder[101]=3
data_holder[102]=3
data_holder[103]=3
data_holder[104]=3
data_holder[105]=3
data_holder[106]=3
data_holder[107]=3
data_holder[108]=3
data_holder[109]=3
data_holder[110]=3
data_holder[111]=3
data_holder[112]=3
data_holder[113]=3
data_holder[114]=3
data_holder[115]=3
data_holder[116]=3
data_holder[117]=3
data_holder[118]=3
data_holder[119]=3
data_holder[120]=3
data_holder[121]=3
data_holder[122]=3
data_holder[123]=3
data_holder[124]=3
data_holder[125]=4
data_holder[126]=4
data_holder[127]=4
data_holder[128]=4
data_holder[129]=4
data_holder[130]=4
data_holder[131]=4
data_holder[132]=4
data_holder[133]=4
data_holder[134]=4
data_holder[135]=4
data_holder[136]=4
data_holder[137]=4
data_holder[138]=4
data_holder[139]=4
data_holder[140]=4
data_holder[141]=4
data_holder[142]=4
data_holder[143]=4
data_holder[144]=4
data_holder[145]=4
data_holder[146]=4
data_holder[147]=4
data_holder[148]=4
data_holder[149]=4
data_holder[150]=5
data_holder[151]=5
data_holder[152]=5
data_holder[153]=5
data_holder[154]=5
data_holder[155]=5
data_holder[156]=5
data_holder[157]=5
data_holder[158]=5
data_holder[159]=5
data_holder[160]=5
data_holder[161]=5
data_holder[162]=5
data_holder[163]=5
data_holder[164]=5
data_holder[165]=5
data_holder[166]=5
data_holder[167]=5
data_holder[168]=5
data_holder[169]=5
data_holder[170]=5
data_holder[171]=5
data_holder[172]=5
data_holder[173]=5
data_holder[174]=5
data_holder[175]=6
data_holder[176]=6
data_holder[177]=6
data_holder[178]=6
data_holder[179]=6
data_holder[180]=6
data_holder[181]=6
data_holder[182]=6
data_holder[183]=6
data_holder[184]=6
data_holder[185]=6
data_holder[186]=6
data_holder[187]=6
data_holder[188]=6
data_holder[189]=6
data_holder[190]=6
data_holder[191]=6
data_holder[192]=6
data_holder[193]=6
data_holder[194]=6
data_holder[195]=6
data_holder[196]=6
data_holder[197]=6
data_holder[198]=6
data_holder[199]=6
data_holder[200]=7
data_holder[201]=7
data_holder[202]=7
data_holder[203]=7
data_holder[204]=7
data_holder[205]=7
data_holder[206]=7
data_holder[207]=7
data_holder[208]=7
data_holder[209]=7
data_holder[210]=7
data_holder[211]=7
data_holder[212]=7
data_holder[213]=7
data_holder[214]=7
data_holder[215]=7
data_holder[216]=7
data_holder[217]=7
data_holder[218]=7
data_holder[219]=7
data_holder[220]=7
data_holder[221]=7
data_holder[222]=7
data_holder[223]=7
data_holder[224]=7
data_holder[225]=8
data_holder[226]=8
data_holder[227]=8
data_holder[228]=8
data_holder[229]=8
data_holder[230]=8
data_holder[231]=8
data_holder[232]=8
data_holder[233]=8
data_holder[234]=8
data_holder[235]=8
data_holder[236]=8
data_holder[237]=8
data_holder[238]=8
data_holder[239]=8
data_holder[240]=8
data_holder[241]=8
data_holder[242]=8
data_holder[243]=8
data_holder[244]=8
data_holder[245]=8
data_holder[246]=8
data_holder[247]=8
data_holder[248]=8
data_holder[249]=8
data_holder[250]=9
data_holder[251]=9
data_holder[252]=9
data_holder[253]=9
data_holder[254]=9
data_holder[255]=9
data_holder[256]=255
data_holder[257]=255
data_holder[258]=255
data_holder[259]=255
data_holder[260]=255
data_holder[261]=255
data_holder[262]=255
data_holder[263]=255
data_holder[264]=255
data_holder[265]=255
data_holder[266]=255
data_holder[267]=255
data_holder[268]=255
data_holder[269]=255
data_holder[270]=255
data_holder[271]=255
data_holder[272]=255
data_holder[273]=255
data_holder[274]=255What is a possible issue here?