Renesas H8 Series, Руководство пользователя

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3.3 Hardware Features
3.3.1 Memory
The emulator provides standard emulation memory as the substitute for on-chip ROM memory and on-chip
RAM memory. When a device type or device mode without an on-chip ROM or on-chip RAM is selected, the
standard emulation memory is disabled. When debugging with only the emulator and the user program and data
are stored in an external address space, an optional SIMM memory module must be used. The optional SIMM
memory modules can be separately purchased.
The emulation memory can be mapped in 64-byte units to any number of separate memory blocks in the MCU
address space. Each memory block can be specified using the memory mapping function as user (Target) or
emulator (SIMM memory module) and, in each case, the access can be specified as read-write, read-only, or
guarded.
The definition of each type of memory is as follows:
Table 3.1 Memory Types
Memory Type Description
On-chip Uses the MCU on-chip memory.
User Accesses the user system memory.
Emulator Accesses the emulator SIMM memory module.
The contents of a specified block of memory can be displayed using the memory function. The contents of
memory can be modified at any time, even during program execution and the results are immediately reflected in
all other appropriate windows.
Note that modifying memory contents during program execution has the following time requirements:
1. MCU on-chip ROM or RAM, or emulator SIMM memory module
The emulator modifies the memory contents by temporarily switching the memory bus to the emulator side
without stopping the user program execution. Therefore, the emulator uses the memory bus for up to 80
µ s in
reading of 256 bytes (25 MHz, on-chip ROM).
2. MCU on-chip I/O, DTCRAM, or user system memory
The emulator stops the user program execution, then modifies the memory contents. Therefore, the user
program stops for a maximum of 2 ms in reading 256 bytes (25 MHz, emulation memory).