M30802MC Datasheet, PDF (76/315 Pages) Mitsubishi Electric Semiconductor – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER

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M16C/80
SINGLE-CHIP
Mitsubishi microcomputers
(144-pin version) group
16-BIT CMOS MICROCOMPUTER
Watchdog timer control register
b7 b6 b5 b4 b3 b2 b1 b0
00
Symbol
WDC
Address
000F16
Bit symbol
Bit name
High-order bit of watchdog timer
Reserved bit
WDC7
Prescaler select bit
When reset
000XXXXX2
Function
Must always be set to “0”
0 : Divided by 16
1 : Divided by 128
Watchdog timer start register
b7
b0
Symbol
WDTS
Address
000E16
When reset
Indeterminate
RW
Function
RW
The watchdog timer is initialized and starts counting after a write instruction to
this register. The watchdog timer value is always initialized to “7FFF16”
regardless of whatever value is written.
System clock control register 0 (Note 1)
b7 b6 b5 b4 b3 b2 b1 b0
Symbol
CM0
Address
000616
When reset
0816
Bit symbol
CM00
CM01
CM02
CM03
Bit
name
Clock output function
select bit (Note 2)
WAIT peripheral function
clock stop bit
XCIN-XCOUT drive capacity
select bit (Note 4)
Function
b1 b0
0 0 : I/O port P53
0 1 : fC output (Note 3)
1 0 : f8 output (Note 3)
1 1 : f32 output (Note 3)
0 : Do not stop f1, f8, f32 in wait mode
1 : Stop f1, f8, f32 in wait mode
0 : LOW
1 : HIGH
RW
CM04
CM05
Port XC select bit
Main clock (XIN-XOUT)
stop bit (Note 5, 6)
0 : I/O port
1 : XCIN-XCOUT generation
0 : On
1 : Off (Note 7)
CM06
Watchdog timer function
select bit
0 : Watchdog timer interrupt
1 : Reset (Note 8)
CM07
System clock select bit
(Note 9)
0 : XIN, XOUT
1 : XCIN, XCOUT
Note 1: Set bit 0 of the protect register (address 000A16) to “1” before writing to this register.
Note 2: When outputting BCLK (bit 7 of processor mode register 0 is "0"), set these bits to "00". When
outputting ALE to P53 (bit 5 and 4 of processor mode register 0 is "01"), set these bits to "00". The
port P53 function is not selected even when you set "00" in microprocessor or memory expansion
mode and bit 7 of the processor mode register 0 is "1".
Note 3: When selecting fC, f8 or f32 in single chip mode, must use P57 as input port.
Note 4: Changes to “1” when shifting to stop mode or reset.
Note 5: When entering power saving mode, main clock stops using this bit. When returning from stop
mode and operating with XIN, set this bit to “0”.
Note 6: When this bit is "1", XOUT is "H". Also, the internal feedback resistance remains ON, so XIN is pulled
up to XOUT ("H" level) via the feedback resistance.
Note 7: When the main clock is stopped, the main clock division register (address 000C16) is set to the
division by 8 mode.
Note 8: When "1" has been set once, "0" cannot be written by software.
Note 9: To set CM07 "1" from "0", first set CM04 to "1", and an oscillation of sub clock is stable. Then set
CM07. Do not set CM04 and CM07 simultaneously. Also, to set CM07 "0" from "1", first set CM05
to "1", and an oscillation of main clock is stable. Then set CM07.
Figure 1.10.2. Watchdog timer control and start registers
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