Modc, Auto OFF / spare, Mode, Oscsel, Romoff

C M L 1 2 S D P 2 5 6

0 7 / 1 7 / 0 2

MODC

The MODC option jumper provides Special Mode enable during Reset. This option must be open or idle when operating with the MON12 or NOICE monitors. If a BDM cable is applied to BDM port, the MODC option must be installed to enable Special Mode. Failure to install the MODC jumper during BDM application may cause communication problems with the host.

AUTO OFF / spare

The AUTO OFF (Spare on REV C. board) option jumper installed defeats the Autostart operation so the MON12 monitor will provide a command prompt. The jumper applies a ground potential to the XIRQ* interrupt line. User should only install the jumper to restore monitor operation, perform the MON12 NOAUTO command to disable the Autostart, and remove or idle the jumper. MON12 operation will then be provided on subsequent Reset conditions.

MODE

The MODE option jumper is not installed on the CML12S-DP256 board and is hard connected by circuit copper trace for Single-chip Mode operation of the CPU. Both the MODA and MODB signals are terminated by this option. Due to the restriction that the HCS12 internal flash memory is the only nonvolatile program memory provided on the board, single Chip Mode is default. All other Modes can be enabled under software control from this mode of operation.

The MODE option jumper may be installed by the user by cutting the hard trace and applying 2 header pins with a shunt jumper. With the shunt jumper removed, the Reset mode will then be Normal Expanded Wide. (Note: mask set 1K79X and earlier will not fetch the Reset vector from external memory in this mode).

OSC_SEL

The OSC_SEL option jumper is not installed on the CML12S-DP256 board. The default configuration is for the provided 4MHz reference crystal to provide the HCS12 oscillator. If the user requires an external clock to be applied, two header pins and shunt jumper can be applied to select the alternate clock source. User should refer to the HCS12 User Guide and CML12S board schematic for proper application of the external clock.

ROM_OFF

The ROM_OFF option jumper is not installed on the CML12S-DP256 board. The default configuration is that the internal flash memory of the HCS12 is enabled at Reset. The user must add external nonvolatile memory to the CML12S board to take advantage of this option. If the external memory is applied, the user may install the two header pins and shunt jumper to select internal or external memory use form Reset.