MITSUBISHI MICROCOMPUTERS
M37274EFSP
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER with CLOSED CAPTION DECODER
and ON-SCREEN DISPLAY CONTROLLER
Table 12. Setting for P63/OSC1/XCIN, P64/OSC2/XCOUT
(4) Clock for OSD
As a clock for display to be used for OSD, it is possible to select one
of the following 4 types.
OSD Clock
I/O Pin
Sub-clock
I/O Pin
Input
Port
Function
Register
Main clock (8 MHz)
b7 of port P3 direction
register
•
0
0
1
Data slicer clock output from the data slicer (approximately 26 MHz)
•
Clock from the LC oscillator supplied from the pins OSC1 and OSC2
•
•
Clock source
1
0
1
1
0
0
0
1
b5
b4
Clock from the ceramic resonator or the quartz-crystal oscillator
control register
from the pins OSC1 and OSC2
This OSD clock for each block can be selected by the following bits
: bit 7 of the port P3 direction register, bits 5 and 4 of the clock source
control register (addresses 021616). A variety of character sizes can
be obtained by combining dot sizes with OSD clocks. When not us-
ing the pins OSC1 and OSC2 for the OSD clock I/O pins, the pins
can be used as sub-clock I/O pins or port P6.
(Note)
Data slicer clock
“0”
Data slicer
circuit
Except “10”
CC mode block
CS0
“1”
“0”
“00”
CS2, CS1
Except “10”
“10”
32 kHZ
OSC1 clock
CS1
OSD mode block
“1”
“0”
CS2 = “0”
CS2, CS1
Except “10”
“10”
LC
CS5, CS4
“11”
Ceramic
•
quartz-crystal
EXOSD mode block
CS3
“1”
CS2, CS1
“10”
Oscillating mode for OSD
Main clock
Clock oscillation
circuit
Note : To use data slicer clock, set bit 0 of data slicer control register to “1.”
Fig. 76. Block Diagram of OSD Selection Circuit
75
RENESAS [ RENESAS TECHNOLOGY CORP ]
