high-memory chip

[jo]

Hi, my project requires a simple chip.. just an IO pin and a large EEPROM memory of ~3KB in one package.

I know that normally a simple chip like PIC12F629 and I2C to a ext EEPROM would be the way out. But is there any microcontroller that can meet the specification? I am open to other microPs if there is none for microchip.

[jo]

[valemike]

After looking at the Microchip website, 1024 bytes internal eeprom seems to be the most you can get out of a PIC.

It's in your best interest (cost-wise) to use a 6-8 pin PIC and external eeprom. well, then again you might not have enough pins for your serial comms lines (i2c or spi) to communicate with the external eeprom, so what's the next size up? an 18 pinner?

[Ttelmah]

What sort of 'write' life is needed?. Remeber on chips supporting direct programming from the code, you can use the main program flash memory for storage, with the 'caveat' that the write life is typically only perhaps one tenth that of the data EEPROM. If the data is only going to change rarely, you might be able to use this as a solution.

Best Wishes

[treitmey]

I like using the I2C interface to fram. The drivers are like a serial eprom. But the fram is faster.
http://www.ramtron.com/doc/Products/overview.asp

[jo]

thanks for all the reply guys...

well, actually the data is going to change fairly often. The main push factor to go for a all-in-one is because the circuit is going to be power up by another device on-contact.

circuit - 'powers up by another device on contact'

When the device 'on-contact' with the circuit, the device will power up my cct and thus to reduce the noise and other factors, i believe a one chip is going to work more reliable. But i guess there is no microP that caters for such scenerios rite?
Or do u guys have any recommendations for such on-contact-powered situations?

[Ttelmah]

There is no reason for 'all in one' to work more reliably in this context. In fact it may often be worse!. You will notice that the larger PIC's, require multiple ground/supply connections, and when you look at even larger chips, the number of power connections is often 30% of the connections to the chip. The problem here is maintaining a smooth supply across a larger die. Realistically, I'd have to recommend a small PIC, perhaps one supporting an internal oscillator, and a FRAM chip. Add a couple of decoupling capacitors, and you have a combination, that in surface mount, could be the size of a nickel, and would do everything you want.

Best Wishes

[jo]

Actually, thats what that was implemented alr in my company current design.. a PIC12 with a EEPROM.. problem is my boss wants it even smaller and more compact.. thats why i am looking for a small chip with big memory(seems ilogical for a manufacturer from my point of view.. but just trying my luck out here... )

[Mark]

You don't mention your current size or what IC packages that you are using.

[jo]

sorry, its a PIC12F629, with 2 IO ports & I2C connection to ext EEPROM usage.

[Mark]

IC's come is various packages. For example, the pic you mention comes in a PDIP, SOIC, DFN-S. The DFN is a 6mmx5mm body. The 10F's are even smaller.

[Ttelmah]

and the FM24LC04 FRAM, comes in SOIC, at 6*4.9mm. The whole combination (exluding power connections, smooting etc.), could fit in 10*6mm.

Best Wishes

[jo]

Thanks guys.

whats about smooth power transfer from one device to another upon contact? Have anyone done that before? I know there is the RF power tranfer and 1-wire parasite power,.. i there any other more option?

Coz u see, i need to improve on the current cct. The present one uses a direct on powering + a diode and cap on the receiving for power smoothing.