MC9S12T64 Datasheet, PDF (113/608 Pages) Motorola, Inc – Specification

Freescale Semiconductor, Inc.
Operating Modes
Operating Modes
Special Test Mode
This mode is intended for Motorola factory testing of the MCU. In
expanded wide modes, Ports A and B are configured as a 16-bit
multiplexed address and data bus and Port E provides bus control and
status signals. In special test mode, the write protection of many control
bits is lifted so that they can be thoroughly tested without needing to go
through reset.
Test Operating
Mode
There is a test operating mode in which an external master, such as an
I.C. tester, can control the on-chip peripherals.
Peripheral Mode
This mode is intended for Motorola factory testing of the MCU. In this
mode, the CPU is inactive and an external (tester) bus master drives
address, data and bus control signals in through Ports A, B and E. In
effect, the whole MCU acts as if it was a peripheral under control of an
external CPU. This allows faster testing of on-chip memory and
peripherals than previous testing methods. Since the mode control
register is not accessible in peripheral mode, the only way to change to
another mode is to reset the MCU into a different mode. Background
debugging should not be used 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.
Operating Modes
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MC9S12T64Revision 1.1.1