====== EEPROM 4K ======

The SST-6809 contains a 32KB EEPROM.

The [[Memory Latch Select 256b]] allows mapping one of eight 4KB sections of the EEPROM into the memory range $F000-$FFFF which includes the MPU interrupt vectors.

Make use of the boot ROM select jumper(s).

The 2.0 can boot from 4 different segments, the 2.1 only 2.

But the current EEPROM only has [[ASSIST09]] burned into it.

The "external ROM" is just the unused space in the other half of the 4k boot ROM.
 
Ken just never put anything there.

At some point Ken could burn another boot into an EEPROM.

The [[PTM]] on the [[Mezzanine board]] can support tracing with [[ASSIST09]], but it needs a jumper to put its interrupt on NMI.

Return to [[:SST-6809:]]