CHAPTER 3 CPU FUNCTION
67
User’s Manual U14492EJ3V0UD
3.3
Operation Modes
3.3.1
Operation modes
The V850E/IA1 has the following operation modes. Mode specification is carried out by the MODE0 to MODE2
pins.
(1) Normal operation mode
(a) Single-chip modes 0, 1
Access to the internal ROM is enabled.
In single-chip mode 0, after the system reset is cleared, each pin related to the bus interface enters the
port mode, program execution branches to the reset entry address of the internal ROM, and instruction
processing starts. By setting the PMCDH, PMCDL, PMCCS, PMCCT, and PMCCM registers to control
mode by instruction, an external device can be connected to the external memory area.
In single-chip mode 1, after the system reset is cleared, each pin related to the bus interface enters the
control mode, program execution branches to the external device’s (memory) reset entry address, and
instruction processing starts. The internal ROM area is mapped from address 100000H.
(b) ROMless modes 0, 1
After the system reset is cleared, each pin related to the bus interface enters the control mode, program
execution branches to the external device’s (memory) reset entry address, and instruction processing
starts. Fetching of instructions and data access for internal ROM becomes impossible.
In ROMless mode 0, the data bus is a 16-bit data bus and in ROMless mode 1, the data bus is an 8-bit
data bus.
(2) Flash memory programming mode (
µµµµ
PD70F3116 only)
If this mode is specified, it becomes possible for the flash programmer to run a program to the internal flash
memory.
The initial values of the registers differ depending on the mode.
Operation Mode
PMCDH
PMCDL
PMCCS
PMCCT
PMCCM
BSC
ROMless mode 0
FFH
FFFFH
FFH
53H
0FH
5555H
ROMless mode 1
FFH
FFFFH
FFH
53H
0FH
0000H
Single-chip mode 0
00H
0000H
00H
00H
00H
5555H
Normal
operation
mode
Single-chip mode 1
FFH
FFFFH
FFH
53H
0FH
5555H
Содержание V850E/IA1 mPD703116
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