24fc1025

bambino

Has anyone used this EEPROM. It's basically the same as the one on the protoboard but has a max bus speed of 1Mhz.
http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1335&dDocName=en024639

Mike Green

I looked at it when I was writing the assembly I2C driver, but I haven't actually used it. I have used a smaller EEPROM in the same series, but not at 1MHz. None of the existing drivers will work at 1MHz, so you'd have to write your own if you want to try it out at the higher speeds.

bambino

So....The one you used was capable of 1Mhz, but you ran it at 400Khz?
That would be fine.

Mike Green

Well, I don't think the assembly I2C driver quite works at 400KHz. Some of the timing is based on minimums for 400KHz, but there's too much overhead in some of the routines to actually transfer data with a 400KHz clock. The bus speed is selectable when you initiate an operation with the assembly routines. 100KHz is the default. Read the comments at the beginning. It's the sdspiFemto.spin object that's part of FemtoBasic.

bambino

Thanks Mike, I just need a boot eeprom , but thought it would be neat to experiment with the higher speeds. I didn't want to get it if it wasn't compatable with the boot loader!

bambino

I was thinking of this chip also because of its capacity, correct me if I'm wrong 1025 means its got 128k bytes right.
I would like to add a sensirion sensor to an app of mine that has like 900 something bytes Longs·left. No room for the float objects required to get 14 bit accuracy from the device. I was hoping to put in, the 96k overhead, a giant look-up table for the temp conversions. But the way they figure capacity in bits has me a little confused! I know I could daisy-chain but I'm running out of real estate too!
Any thoughts!

Post Edited (bambino) : 3/26/2008 10:48:17 PM GMT