M37221M4H_15 Datasheet, PDF (66/114 Pages) Renesas Technology Corp – SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER for VOLTAGE SYNTHESIZER with ON-SCREEN DISPLAY CONTROLLER

M37221M4H/M6H/M8H/MAH–XXXSP/FP M37221EASP/FP
8.11.3 Clock for OSD
The following 2 types of clocks can be selected for OSD display.
• Main clock supplied from XIN pin
• Main clock supplied from XIN pin divided by I.5
• Clock from the ceramic resonator or the LC or oscillator from the
pins OSC1 and OSC2
• Clock from the ceramic resonator or the quartz-crystal oscillator
supplied from pins OSC1 and OSC2.
The OSD clock for each block can be selected by the OSD clock
selection register (address 00ED16).
When selecting the main clock, set the oscillation frequency to
8 MHz.
OSD Clock Selection Register
b7 b6 b5 b4 b3 b2 b1 b0
000000
OSD clock selection register (CK) [Address 00ED16]
B
Name
Functions
After reset R W
0, 1 OSD clock b1 b0
Functions
selection bits _{0 0 The clock for display is supplied by connecting RC}
(CK0,CK1)
or LC across the pins OSC1 and OSC2.
0
RW
0 1 Since the main clock is used as the OSD oscillation
clock for display, the oscillation
frequency
frequency is limited. Because of this, = f(XIN)
the character size in width (horizontal)
1 0 _{direction is also limited. In this case,} OSD oscillation
pins OSC1 and OSC2 are also used ^frequency
as input ports P33 and P34 respectively. ^{= f(XIN)/1.5}
1 1 The clock for OSD is supplied by connecting the
following across the pins OSC1 and OSC2.
• a ceramic resonator only for OSD
• a quartz-crystal oscillator only for OSD and a
feedback resistor (See note)
2 to 7 Fix these bits to “0.”
0
RW
Note: It is necessary to connect other ceramic resonator or quartz-crystal oscillator for OSD across the pINs XIN and XOUT.
Fig. 8.11.10 OSD clock selection Circuit
Rev.1.00 Oct 01, 2002 page 64 of 110
REJ03B0134-0100Z