do you know if there is an existing schematic for connect an external EEPROM with a MC9S12P64VLH?
I think we can use a ATMEL25640 on the Pin 58 ,57,56,55 (MISO0,/SSO,MOSI0,/SCK0). Do you know the best circuit?
The S12P features SPI module (MISO0,/SSO,MOSI0,/SCK0) as well, so you can use this serial interface for external EEPROM.
Below post can be of help as an alternative:
External Serial EEPROM | Freescale Community
Moreover, there is an appnote for S12P devices about EEPROM emulation (it comes with the SW driver), so you might not need to use external EEPROM:
AN4483, Emulated EEPROM Routines for the S12P Family - Application Notes
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