mc9s12xf512 Freescale Semiconductor, Inc, mc9s12xf512 Datasheet - Page 831

• Manufacturer Part Number: mc9s12xf512
• Description: S12x Microcontrollers 16-bit Automotive Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

The associated timing numbers for both operations are given in
It is recommended to use the free-running clock (ECLK) at the fastest rate (bus clock rate) to synchronize
the EWAIT input signal.
18.5.2
In emulation mode applications, the development systems use a custom PRU device to rebuild the single-
chip or expanded bus functions which are lost due to the use of the external bus with an emulator.
Accesses to a set of registers controlling the related ports in normal modes (refer to SoC section) are
directed to the external bus in emulation modes which are substituted by PRR as part of the PRU. Accesses
to these registers take a constant time of 2 cycles.
Depending on the setting of ROMON and EROMON (refer to S12X_MMC section), the program code
can be executed from internal memory or an optional external emulation memory (EMULMEM). No wait
state operation (stretching) of the external bus access is done in emulation modes when accessing internal
memory or emulation memory addresses.
In both modes observation of the internal operation is supported through the external bus (internal
visibility).
18.5.2.1
This mode is used for emulation systems in which the target application is operating in normal single-chip
mode.
Figure 18-5
Freescale Semiconductor
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Table ‘Example 1b: Normal Expanded Mode Timing V
Table ‘Example 1b: Normal Expanded Mode Timing V
Emulation Modes
shows the PRU connection with the available external bus signals in an emulator application.
Example 2a: Emulation Single-Chip Mode
MC9S12XF - Family Reference Manual, Rev.1.19
DD5
DD5
= 5.0 V (EWAIT enabled)’
= 3.0 V (EWAIT enabled)’
Chapter 18 External Bus Interface (S12XEBIV4)
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