M16C80 Datasheet, PDF (58/358 Pages) Renesas Technology Corp – RENESAS 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/80 SERIES

M16C/80 Group
8. Clock Generating Circuit
Main clock division register (Note 1)
b7 b6 b5 b4 b3 b2 b1 b0
Symbol
MCD
Address When reset
000C16 XXX010002
Bit symbol
MCD0
MCD1
MCD2
MCD3
MCD4
Bit name
Main clock division select
bit (Note 2)
Function
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
RW
Nothing is assigned.
When write, set "0". When read, their contents are indeterminate.
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.
Figure 8.5 Main clock division register
8.3 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 8.2 shows clock output setting (single chip mode) and Table 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.
Rev.1.00 Aug. 02, 2005 ^{Page 47} of 329
REJ09B0187-0100