CHAPTER 3 CPU FUNCTION
70
User’s Manual U14359EJ4V0UM
3.3 Operating Modes
3.3.1 Operating modes
The V850E/MA1 has the following operating modes. Mode specification is carried out using 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 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 PMCAL, PMCAH, PMCDL, PMCCS, PMCCT, PMCCM, and PMCCD
registers to control mode by instruction, an external device can be connected to the external memory
area.
In single-chip mode 1, after 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 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
PD70F3107A only)
If this mode is specified, it becomes possible for the flash programmer to run a program to the on-chip flash
memory.
The initial value of the register differs depending on the mode.
Operating Mode
PMCAL
PMCAH
PMCDL
PMCCS
PMCCT
PMCCM
PMCCD
BSC
ROMless mode 0
FFFFH
03FFH
FFFFH
FFH
F3H
3FH
0FH
5555H
ROMless mode 1
FFFFH
03FFH
FFFFH
FFH
F3H
3FH
0FH
0000H
Single-chip mode 0
0000H
0000H
0000H
00H
00H
00H
00H
5555H
Normal
operation
mode
Single-chip mode 1
FFFFH
03FFH
FFFFH
FFH
F3H
3FH
0FH
5555H