Datasheet

Operating Modes

Technical Data MC68HC912DT128A — Rev 4.0

82 Operating Modes MOTOROLA

while the MCU is in special peripheral mode as internal bus

conflicts between BDM and the external master can cause

improper operation of both functions.

The MODE register controls the MCU operating mode and various

configuration options. This register is not in the map in peripheral mode

SMODN, MODB, MODA — Mode Select Special, B and A

These bits show the current operating mode and reflect the status of

the BKGD, MODB and MODA input pins at the rising edge of reset.

Read anytime.

SMODN may only be written if SMODN = 0 (in special modes) but the

first write is ignored.

MODB, MODA may be written once if SMODN = 1; anytime if SMODN

= 0 but the first write is ignored and in special peripheral and reserved

modes cannot be selected.

Bit 7654321Bit 0

SMODN MODB MODA ESTR IVIS EBSWAI EMK EME

RESET: 0 0 0 1 1 0 1 1 Special Single Chip

RESET: 0 0 1 1 1 0 1 1 Special Exp Nar

RESET: 0 1 0 1 1 0 1 1 Peripheral

RESET: 0 1 1 1 1 0 1 1 Special Exp Wide

RESET: 1 0 0 1 0 0 0 0 Normal Single Chip

RESET: 1 0 1 1 0 0 0 0 Normal Exp Nar

RESET: 1 1 1 1 0 0 0 0 Normal Exp Wide

MODE — Mode Register $000B

Frees

cale Semiconductor,

Freescale Semiconductor, Inc.

For More Information On This Product,

Go to: www.freescale.com

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