Getting More From Your EEPROM Slot
Brian Riley
Posts: 626
First stop on the Propeller CPU board tour is the PPDB or any single slot Prop EEPROM board that originally came with a Microchip 24LC256 (32KB) or 24LC512 (64KB). Now these chips have pins 1,2,&3 for A0, A1, and A2. But the next chip larger the 24LC1025 (128KB) is not quite the same ... it wants A2 pulled up and it differentiates chips with A0 and A1 and software.
Enter the Atmel AT24C1024B. Same command structure and size. Differentiates chips on A1 and A2. Pin 1 has No Connection. Now this chip will seat mechanically and electrically in a socket addressed as 0 (pins 1,2,&3 to GND - Pin 1 is NC but doesn't care if it is grounded)
Power up, loaded a program to EEPROM ... all OK. I loaded PropForth v5 EEPROM configuration, It has an auto-recognize and sizes the EEPROM and it read 131,000+ bytes .... success!
Just for grins I loaded up Peter Jakacki's Tachyon Forth VM with EEPROM support and its power up test reported two devices. I assume this is correct ... each 'device' representing one 64KB address block.
I have just received prototype boards with two EEPROM sockets address as 0 and 1 for the Atmel 1024 part. As soon as I build it up I will test it and report the results.
Meanwhile PPDB and similar single sockets boards can boost their EEPROM capacity with a simple chip switch costing about $3.
The Mouser p/n: 556-AT24C1024BPU25
Enter the Atmel AT24C1024B. Same command structure and size. Differentiates chips on A1 and A2. Pin 1 has No Connection. Now this chip will seat mechanically and electrically in a socket addressed as 0 (pins 1,2,&3 to GND - Pin 1 is NC but doesn't care if it is grounded)
Power up, loaded a program to EEPROM ... all OK. I loaded PropForth v5 EEPROM configuration, It has an auto-recognize and sizes the EEPROM and it read 131,000+ bytes .... success!
Just for grins I loaded up Peter Jakacki's Tachyon Forth VM with EEPROM support and its power up test reported two devices. I assume this is correct ... each 'device' representing one 64KB address block.
I have just received prototype boards with two EEPROM sockets address as 0 and 1 for the Atmel 1024 part. As soon as I build it up I will test it and report the results.
Meanwhile PPDB and similar single sockets boards can boost their EEPROM capacity with a simple chip switch costing about $3.
The Mouser p/n: 556-AT24C1024BPU25
Comments
Been meaning to check out Peter's TACHYON FORTH for a while.
Thanks for the info!
Jim
Thanks for your work. I couldn't find that exact PN (The Mouser p/n: 556-AT24C1024B-PU25) so I searched for:
Atmel AT24C1024. This returns 9 hits. Of those, one is DIP, 3.3 v and 1Mhz. Will this work?
Mouser Part #: 556-A24C1024BPU25
Manufacturer Part #: AT24C1024B-PU25
Dumb question, can this be setup to run at 1Mhz on the Prop? Thanks!
The "25" signifies 2.5 to 5.5v operation, it is DIP-8
Usefull info, thanks. For the search impaired (like me):
http://www.mouser.com/ProductDetail/Atmel/AT24C1024B-PU25/?qs=j6lVIf5KywDc%2bnjW4IKuatbmz45vTZgV
Does anyone know about 1Mhz operation?
It all worked out fine ... PropForth EEPROM (V 5.2.1) code read the EEPROMTop as 261,144 and Tachyon 1208006.0000 read the two EEPROMs as 4 64K devices
So ... the Prop bootloader, and both current Forths (PropForth and Tachyon) read and write to multiple AT24C1024Bs ... and now back to figuring out what's wrong with the PCB and maybe wiring up a third and fourth EEPROM.