EEPROM verify error using 24LC1025

northcove

Hi there,

This morning I've upgraded my Propeller project's EEPROM from the 64kbyte 24LC512 chip to the larger 128kbyte 24LC1025 version from the same manufacturer, Microchip. Both chips are the 400kHz versions running at 3.3VDC. The I/O timing specs look identical. I'm using 2k ohm pull ups on the clock and data lines. Datasheet for the 24LC1025 is http://www.microchip.com/mymicrochip/filehandler.aspx?ddocname=en022469

Now Propeller Tool 1.3.2 usually (but not always) generates an EEPROM verify error after an F11 using the new EEPROMs.

Has anyone encountered this before?

Thanks,

northcove

Duane Degn

I'm just spouting back what I've read on the forum but I think the problem is the 24LC1025 uses 128 byte pages. The Propeller expects 64 byte pages (IIRC). There are 128KB EEPROMs available which will work with the Propeller but I don't recall their numbers off hand.

You could still use the 24LC1025 for data storage but you won't be able to boot from it.

northcove

Thanks but I don't think the 128 byte page size is the issue. A 128 byte page size should be compatible with any Tool I/O hardcoded for 64 byte page boundaries.

Also, the Propeller Tool succeeds in programming the 128kb EEPROM about 1 out of every 5 attempts. The Prop boots fine on the times it doesn't get an EEPROM verify error from the Propeller Tool.

I'm thinking the cause is related to the Propeller Tool -> USB -> EEPROM I/O activity that either writes data to the EEPROM or checkums memory ranges in the EEPROM.

Any idea what 128kbyte EEPROMs are proven compatible with the Propeller?

Cheers,

Christopher

Duane Degn

northcove wrote: »

Thanks but I don't think the 128 byte page size is the issue. A 128 byte page size should be compatible with any Tool I/O hardcoded for 64 byte page boundaries.

Interesting. I had thought the page size had to be the same. I guess the page size just can't be smaller than 64 bytes.

northcove wrote: »

Any idea what 128kbyte EEPROMs are proven compatible with the Propeller?

I know there are a couple of different 128Kbyte EEPROMs which will work with the Propeller. I have a 24AA1026 in one of my boards and I know it works fine.

BEEP

" *A2 must be tied to VCC. "
Could this be the problem?

ozpropdev

The 24LC1025 is all I use on my projects.
I use a 4K7 pull up resistor on SDA if that helps.

Mike Green

The 24LC1025 has a "wonky" addressing scheme. Address pin A2 HAS to be connected to Vdd for the chip to work as stated clearly on page 5 of the datasheet. In addition, there are 8 64K byte blocks available in the address space, 2 for each 24LC1025. Blocks 0-3 refer to the 1st 64K bytes of each of 4 possible 24LC1025 chips on an I2C bus while blocks 4-7 refer to the 2nd 64K bytes of each of 4 possible 24LC1025 chips on the I2C bus. Look at the datasheet for details.

Atmel makes a similar chip, the AT24C1024, which has a more straightforward addressing scheme, but is limited to two such chips on a single I2C bus.

northcove

Mike & Beep - thanks for your sharp eyes. After quickly glancing the 1st & 2nd pages of their respective data sheets I naively assumed the 24LC1025 would be identical to the 24LC512. Quite odd that the 1025 was successfully programmed about one out of every 5 attempts though.