NVSRAM vs. EEPROM

Compare the two. I'm designing an 8-bit CPU and I want to know which is better for program storage.

bitbyteword3 said:

Compare the two. I'm designing an 8-bit CPU and I want to know which is better for program storage.

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Conventionally in 8 bit CPU's , the 'program' is in UV eraseable ROM or EEPROM, with 'data' memory in RAM or Non volatile RAM.

Ill mannered code can corrupt itself in RAM, making debugging difficult. It's just better practice to put it where access/alteration is a process.

We used NV SRAM in a Display unit... never again! Some (quite cold) boot ups destroy's the data... Moved to EEPROM never done it since..

Ian Rogers said:

We used NV SRAM in a Display unit... never again! Some (quite cold) boot ups destroy's the data... Moved to EEPROM never done it since..

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Funnily enough, one of the major causes of faults in TV's over the last decade or two has been EEPROM corruption - and this includes Plasma and LCD.

Sharp were one of the main offenders, and even brought out sets that kept three copies of the data, and compared all three - correcting if one was faulty (those sets suffered from EEPROM corruption as well).

I suspect this is why PIC's require the complicated 0x55/0xAA to write to their data EEPROM.

Funny that Nigel! Its microchip EEPROMS we use now 24LC256 I think these have internal coding.

Of course we moved to I2C instead of parallel

Ian Rogers said:

Funny that Nigel! Its microchip EEPROMS we use now 24LC256 I think these have internal coding.

Of course we moved to I2C instead of parallel

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The ones in the TV's were obviously I2C (it's what I2C was designed for), and make seemed to make difference.