EEPROM on '24N

[Don_Kirby]

As the 2526A is still on the board on a 24N, does this mean I get another chunk of EEPROM to use?


-Don

[dkinzer]

As the 2526A is still on the board on a 24N, does this mean I get another chunk of EEPROM to use?

Well, it is EEPROM but it is not part of the Persistent Memory space (which is internal EEPROM).

You can read data from it and write data to it using SPICmd().

[Don_Kirby]

Perhaps this should be less ambiguous.

Bearing in mind that the 24n devices recently shipped are beta devices, is the plan to use the same 24 or 24a hardware for the n devices, leaving the SPI EEPROM on the board, or is the plan to remove the chip for the release version of the N devices.

If it is the former, perhaps the compiler could integrate the extra memory, and treat it as standard persistent storage rather than using SPICmd().

-Don

[dkinzer]

s the plan to use the same 24 or 24a hardware for the n devices, leaving the SPI EEPROM on the board?

Yes, that is the plan. Everything is the same except the processor is an ATmega644P with different firmware.

[spamiam]

The 644P is able to use a pretty low voltage supply. What is the lower limit of voltage for the overall device?

-Tony

[dkinzer]

What is the lower limit of voltage for the overall device?

To remain within spec at 14.7456MHz, the supply voltage must be at least 3.55 volts. According to the datasheet, the supply voltage vs frequency curve is linear from 2.7V @ 10MHz to 4.5V @ 20MHz.

[spamiam]

So, the inverter and the EEPROM will function at that voltage too?

-Tony

[dkinzer]

So, the inverter and the EEPROM will function at that voltage too?

The inverter is not a problem at all. The operating voltage for it is 2.0 to 5.0 volts. The specs for the EEPROM are similar to those of the AVR. At 2.7V it is specified to operate at 10MHz and at 4.5V it can go to 20MHz. I suspect that the voltage/frequency curve is linear between those points as it is with the AVR.