Under
development
Preliminary Specifications REV.D
Specifications in this manual are tentative and subject to change.
Mitsubishi Microcomputers
M16C/80 group
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
Clock Generating Circuit
47
Figure 1.8.5. Main clock division register
Main clock division register (Note 1)
Symbol
Address
When reset
MCD
000C16
XXX010002
Bit name
Function
Bit symbol
b7
b6
b5
b4
b3
b2
b1
b0
1 0 0 1 0 : No division mode
0 0 0 1 0 : Division by 2 mode
0 0 0 1 1 : Division by 3 mode
0 0 1 0 0 : Division by 4 mode
0 0 1 1 0 : Division by 6 mode
0 1 0 0 0 : Division by 8 mode
0 1 0 1 0 : Division by 10 mode
0 1 1 0 0 : Division by 12 mode
0 1 1 1 0 : Division by 14 mode
0 0 0 0 0 : Division by 16 mode
b4 b3 b2 b1 b0
MCD4
MCD3
MCD1
MCD2
MCD0
Main clock division select
bit (Note 2)
Note 1: Set bit 0 of the protect register (address 000A16) to “1” before writing to
this register.
Note 2: These bits are "010002" (8-division mode) when main clock is stopped
or you shift to stop mode.
Note 3: Do not attempt to set combinations of values other than those shown in
this figure.
W
R
Nothing is assigned.
When write, set "0". When read, their contents are indeterminate.
Clock Output
In single chip mode, when the BCLK output function select bit (bit 7 at address 000416 :PM07) is “1”, you
can output f8, f32, or fc from the P53/BCLK/ALE/CLKOUT pins by setting the clock output function select
bits (bits 1 and 0 at address 000616 :CM01, CM00).(Note)
Even when you set PM07 to “0” and CM01 and CM00 to “002”, no BCLK is output.
In memory expansion mode or microprocessor mode, when the ALE pin select bits (bits 5 and 4 at ad-
dress 000516 :PM15, PM14) are other than “012(P53/BCLK)” and PM07 is “1”, you can output f8, f32, or fc
from the P53/BCLK/ALE/CLKOUT pins by setting CM01 and CM00.
In memory expansion mode or microprocessor mode, when PM15 and PM14 are other than “012(P53/
BCLK)” and PM07 is “0” and CM01 and CM00 to “002”, BCLK is output from the P53/BCLK/ALE/CLKOUT
pins.
When stopping clock output in memory expansion mode or microprocessor mode, set PM07 to “1” and
CM01 and CM00 to “002” (IO port P53). The P53 function is not selected. When PM15 and PM14 are “012
(P53/BCLK)” and CM01 and CM00 are “002”, PM07 is ignored and the P53 pin is set for ALE output.
When the WAIT peripheral function clock stop bit (bit 2 at address 000616) is set to “1”, f8 or f32 clock
output is stopped when a WAIT command is executed.
Table 1.8.2 shows clock output setting (single chip mode) and Table 1.8.3 shows clock output setting
(memory expansion/microprocessor mode).
Note :When outputting the f8, f32 or fc from port P53/BCLK/ALE/CLKOUT pin in single chip mode, use port
_______
P57/RDY as an input only port.