S912XEG128J2MAA Datasheet, PDF (224/1324 Pages) Freescale Semiconductor, Inc – Microcontrollers

Chapter 3 Memory Mapping Control (S12XMMCV4)
3.5.3.4 ROM Control in Emulation Expanded Mode
In emulation expanded mode the external bus will be connected to the emulator and to the application. If
the ROMON bit is set, the internal FLASH provides the data. If the EROMON bit is set as well the
emulator observes all CPU internal actions, otherwise the emulator provides the data and traces all CPU
actions (see Figure 3-27). When the ROMON bit is cleared, the application memory provides the data and
the emulator will observe the CPU internal actions (see Figure 3-28).
MCU
Emulator
Observer
Flash
Application
MCU
Memory
EROMON = 1
Emulator
Generator
Flash
Application
Memory
EROMON = 0
Figure 3-27. ROMON = 1 in Emulation Expanded Mode
MC9S12XE-Family Reference Manual Rev. 1.25
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Freescale Semiconductor