Operating Mode

[BaileyAmps]

What operating CPU mode is the NMIS/L-0012 designed to operate in? It looks from the wiring diagram that Port B is the only port wired to the memory socket. When I looked in the MC68HC12B manual there doesn't appear to be any modes that use just Port B for off-chip memory access. Does anyone have any C code that shows an example of a program that's stored in the FLASH EEPROM and runs in the off-chip RAM?

[rob]

> What operating CPU mode is the NMIS/L-0012 designed to operate in?

When it boots up, only the internal memories are enabled but if part of
the dictionary is in external memory, then external memory is enabled.

>It looks from the wiring diagram that Port B is the only port wired to the
>memory socket.

The memory socket is just an 8 bit memory bus, so only port C is used
for data. Ports A and B are used to support the external memory bus.

>When I looked in the MC68HC12B manual there doesn't appear
>to be any modes that use just Port B for off-chip memory access. Does
>anyone have any C code that shows an example of a program that's stored in
>the FLASH EEPROM and runs in the off-chip RAM?

To access the external memory you will need to set registers first:
PEAR = 0x04; // set PE2 on port E as R/W
MODE = 0xB0; // set mode register to Normal expanded narrow, only once

Rob

[rob]

>The memory socket is just an 8 bit memory bus, so only port C is used
>for data. Ports A and B are used to support the external memory bus.

Ignore that, it is for the A4. For the B32, the B port is the lower
address byte and the A port is demultiplexed with U3 (74HC573) to
provide the upper address byte and data bus.