M306H2MC-XXXFP Datasheet, PDF (35/210 Pages) Renesas Technology Corp – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER with DATA ACQUISITION CONTROLLER

MITSUBISHI MICROCOMPUTERS
M306H2MC-XXXFP
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
with DATA ACQUISITION CONTROLLER
Figure 2.5.4 shows the system clock control registers 0 and 1.
System clock control register 0 (Note 1)
b7 b6 b5 b4 b3 b2 b1 b0
Symbol
CM0
Address
000616
When reset
4816
Bit symbol
CM00
CM01
CM02
CM03
CM04
CM05
Bit name
Clock output function
select bit
(Valid in single-chip
mode only)
WAIT peripheral function
clock stop bit
XCIN-XCOUT drive capacity
select bit (Note 2)
Port XC select bit
Main clock (X IN-XOUT)
stop bit (Notes 3,4,5)
b1 b0
0 0 : I/O port P5 7
0 1 : Output f c
1 0 : Output f 8
1 1 : Output f 32
Function
RW
0 : Do not stop peripheral function clock in wait mode
1 : Stop peripheral function clock in wait mode (Note 8)
0 : LOW
1 : HIGH
0 : I/O port
1 : XCIN-XCOUT generation
0 : On
1 : Off
CM06
Main clock division select 0 : CM16 and CM17 valid
bit 0 (Note 7)
1 : Division by 8 mode
CM07
System clock select bit
(Note 6)
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: Changes to “1” when shifting to stop mode and at a reset.
Note 3: When entering power saving mode, main clock stops using this bit. When returning from stop mode and
operating with X IN, set this bit to “0”. When main clock oscillation is operating by itself, set system clock select
bit (CM07) to “1” before setting this bit to “1”.
Note 4: When inputting external clock, only clock oscillation buffer is stopped and clock input is acceptable.
Note 5: If this bit is set to “1”, X OUT turns “H”. The built-in feedback resistor remains being connected, so XIN turns
pulled up to X OUT (“H”) via the feedback resistor.
Note 6: Set port Xc select bit (CM04) to “1” and stabilize the sub-clock oscillating before setting to this bit from “0” to “1”.
Do not write to both bits at the same time. And also, set the main clock stop bit (CM05) to “0” and stabilize the
main clock oscillating before setting this bit from “1” to “0”.
Note 7: This bit changes to “1” when shifting from high-speed/medium-speed mode to stop mode and at a reset. When
shifting from low-speed/low power dissipation mode to stop mode, the value before stop mode is retained.
Note 8: fC32 is not included. Do not set this bit to “1” in the low-speed/ low-power dissipation mode.
Note 9: When the XCIN/XCOUT is used, set ports P86 and P87 as the input ports without pull-up.
System clock control register 1 (Note 1)
b7 b6 b5 b4 b3 b2 b1 b0
0000
Symbol
CM1
Address
000716
When reset
2016
Bit symbol
Bit name
CM10
All clock stop control bit
(Note4)
Function
0 : Clock on
1 : All clocks off (stop mode)
RW
Reserved bit
Always set to “0”
CM15
CM16
CM17
XIN-XOUT drive capacity
select bit (Note 2)
Main clock division
select bit 1 (Note 3)
0 : LOW
1 : HIGH
b7 b6
0 0 : No division mode
0 1 : Division by 2 mode
1 0 : Division by 4 mode
1 1 : Division by 16 mode
Note 1: Set bit 0 of the protect register (address 000A 16) to “1” before writing to this register.
Note 2: This bit changes to “1” when shifting from high-speed/medium-speed mode to stop mode and at a reset. When
shifting from low-speed/low power dissipation mode to stop mode, the value before stop mode is retained.
Note 3: Can be selected when bit 6 of the system clock control register 0 (address 0006 16) is “0”. If “1”, division mode is
fixed at 8.
Note 4: If this bit is set to “1”, XOUT turns “H”, and the built-in feedback resistor is cut off. XCIN and XCOUT turn high-
impedance state.
Figure 2.5.4 Clock control registers 0 and 1
Rev. 1.0
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