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Topic: Can someone combine multiple eeprom chips together as one? (Read 417 times) previous topic - next topic

josephchrzempiec

Hello i know this is a far fetch question but is there away to combine 2 or more eeprom chips as a single chip? Just wondering some thoughts in my mind.

robtillaart

you could make an abstract library or a wrapper that hides the individual addressing

a bit like this

Code: (NOT tested) [Select]
void eepromWrite(uint32_t memAddress, uint8_t data)
{
  uint8_t table[] = { 0x80, 0x81, 0x82, 0x83 }; // example I2C addresses

  uint8_t I2Caddress = table[ memAddress / EEPROMSIZE] ; // e.g. 32768;

  uint16_t_addr = memAddress % EEPROMSIZE; // address within chip

  I2CEEPROM.write(I2Caddress, addr, data):
}

uint8_t eepromRead(uint32_t memAddress)
{
  uint8_t table[] = { 0x80, 0x81, 0x82, 0x83 }; // example I2C addresses

  uint8_t I2Caddress = table[ memAddress / EEPROMSIZE] ; // e.g. 32768;

  uint16_t_addr = memAddress % EEPROMSIZE; // address within chip

  return I2CEEPROM.read(I2Caddress, addr):
}


my eeprom lib might be a base to extend
- http://playground.arduino.cc/Main/LibraryForI2CEEPROM -
Rob Tillaart

Nederlandse sectie - http://arduino.cc/forum/index.php/board,77.0.html -
(Please do not PM for private consultancy)

josephchrzempiec

Thank you this is just a future project not sure of it but thank you for comfirmig with me something can be done.
I'll post a update in the near future if i decide to make this project.

josephchrzempiec

Hello robtillaart i have one question is there a wau to only write to a external eeprom chip once and never right to it again?
But keep it as many reads as it can do?

CrossRoads

Yes.
Many (most? all?) serial interface I2C and SPI EEPROMs have a write protect pin, you can tie that high or low (read the datasheet) to prevent writes after the initial loading.

Read the datasheet for the parts you are using to see if there are software means to prevent writing also.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

josephchrzempiec

#5
Jan 12, 2015, 03:51 pm Last Edit: Jan 12, 2015, 06:16 pm by josephchrzempiec
Hello crossroads thank you. My problem is I build this board in a enclosure box sealed so can't be reopen. That is my problem I have a visual Basic application that I can write to the eeprom chip and it's displays on lcd  what is saved. But I would like to somehow block it from writing again in software from the arduino ide.

josephchrzempiec

i think i might have to brake open the project and wire up that pin. so if i write to the eeprom chip and send it i guess it can make the pin go high/low to disable the write so it can be only written to it once that might be okay.

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