Hey Guys,

I am preparing to use a Parallax Propeller Microcontroller. The MCU's program can either be inputted into the chip directly via USB or read into the chip by way of external 32K Serial EEPROM. I would like to use the external memory option, however, I would like to be able to substitute the EEPROM if I can with a 28C256 Paged EEPROM because it is readily available. I would have to make a few modifications to the circuit because the MCU communicates to external memory serially (Address/Data I/O, Clock). Can you guys offer me any options available to connect a serial MCU with a parallel memory chip?

I believe that I can communicate with memory if I connect its data output pins to a PISO shift register and connect the register's clock to the MCU's clock and have the data shifted out of the register every pulse.

 

Even the most simple circuit would cost more than a commonly available 256kb serial EEPROM. What part of the world can get a Parallax Propeller but not a 24LC256?

 

The schematic calls for 256K but Jameco does not have the 24LC256 at the moment. Will I be able to use a 24C512? I assume this means that the circuit will still work but I will have more space than necessary?

 

The 512 might work, try the Parallax forums for an accurate answer.