m3819 Renesas Electronics Corporation., m3819 Datasheet - Page 22

• Manufacturer Part Number: m3819
• Description: Mitsubishi 8-bit Single-chip Microcomputer 740 Family / 38000 Series
• Manufacturer: Renesas Electronics Corporation.

FUNCTIONAL DESCRIPTION
Central Processing Unit (CPU)
The 3819 group uses the standard 740 family instruction set. Re-
fer to the table of 740 family addressing modes and machine
instructions or the 740 Family Software Manual for details on the
instruction set.
Machine-resident 740 family instructions are as follows:
The FST, SLW instruction cannot be used.
The MUL, DIV, WIT and STP instruction can be used.
Fig. 1 Structure of CPU mode register
8
b7
b0
CPU mode register
(CPUM (CM) : address 003B
Processor mode bits
Stack page selection bit
X
Port X
Main clock (X
Main clock division ratio selection bit
Internal system clock selection bit
COUT
b1 b0
0 0 : Single-chip mode
0 1 :
1 0 : Not available
1 1 :
0 : RAM in the zero page is used as stack area
1 : RAM in page 1 is used as stack area
0 : Low drive
1 : High drive
0 : I/O port function
1 : X
0 : Oscillating
1 : Stopped
0 : f(X
1 : f(X
0 : X
1 : X
C
drivability selection bit
CIN
IN
CIN
CPU Mode Register
The CPU mode register is allocated at address 003B
mode register contains the stack page selection bit and the inter-
nal system clock selection bit.
switch bit
IN
IN
-X
-X
-X
)/2 (high-speed mode)
)/8 (middle-speed mode)
OUT
COUT
COUT
IN
selected (middle/high-speed mode)
-X
selected (low-speed mode)
oscillating function
OUT
) stop bit
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
16
)
MITSUBISHI MICROCOMPUTERS
3819 Group
16
. The CPU