If EEPROM dies, is MCP4706 DAC chip still OK?

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If EEPROM dies, is MCP4706 DAC chip still OK?

Post by treez » Wed Sep 10, 2014 11:28 am

We need a single channel DAC chip , between 8 to 12 bits.
We found the MCP4706, however, it has EEPROM.
We do not need EEPROM and so do not want it, as EEPROM dies after so many read/writes and that will then render the MCP4706 “dead”.
We want it to last and not die on us.

Do you know of a similar chip to MCP4706 that doesn’t have EEPROM?….they all seem to have it.

We only need to write to the DAC once every hour or so.

We wish to load values by bit-bashing the I2C protocol..is this OK?….we do not know how to use the I2C module inside our PIC18F65K22 microcontroller.

MCP4706 DAC datasheet
http://ww1.microchip.com/downloads/en/D ... 22272C.pdf

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Re: If EEPROM dies, is MCP4706 DAC chip still OK?

Post by skimask » Wed Sep 10, 2014 12:22 pm

EEPROM life cycle = 1,000,000
Once per hour = ~114+ years.
Think the DAC is still going to be in use in 114 years?
I ignore "one post wonders".

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Re: If EEPROM dies, is MCP4706 DAC chip still OK?

Post by jremington » Wed Sep 10, 2014 8:20 pm

Agreed that the EEPROM is not an issue, especially in the proposed application, but there are many other options. Consider the Maxim line of DACs, which do not have EEPROM. Here is the selection guide (Maxim gives out free samples): http://para.maximintegrated.com/en/sear ... %20-%20SPI

Of course you can bit-bang the I2C protocol, but with a little study of the data sheet (and some help from Google), it should be pretty easy to use the built-in I2C module.

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Re: If EEPROM dies, is MCP4706 DAC chip still OK?

Post by n1ist » Thu Sep 11, 2014 11:18 am

A quick glance at the data sheet shows that you can write the DAC directly (write volatile command) without touching the EEPROM. In that case, the EEPROM is just used to set the power-up value (which you can of course overwrite as soon as your processor comes up...)

As for bit-banging I2C, yes, it's doable. Just remember that the pins are open-collector or open-drain; you can mimic this by setting your port to 0 and driving the direction bit instead of the port bit.



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