M35061 Datasheet, PDF (28/40 Pages) Mitsubishi Electric Semiconductor – SCREEN CHARACTER and PATTERN DISPLAY CONTROLLERS

MITSUBISHI MICROCOMPUTERS
M35061-XXXSP/FP
SCREEN CHARACTER and PATTERN DISPLAY CONTROLLERS
Notes on others
1. At system start-up
At system start-up, always set the AC pin to low level before setting
registers.
2. Power supply noise
When power supply noise is generated, the internal oscillator circuit
does not stabilize, whereby causing horizontal jitters across the pic-
ture display. Therefore, connect a bypass capacitor between the
power supply and GND.
3. At power on
When power to the M35061-XXXSP/FP is activated, characters are
sometimes output without defining the internal display RAM, com-
posite RAM and register. Also, immediately after power is turned on,
up until the oscillator circuit stabilizes, data is sometimes not set cor-
rectly in the register. Therefore, use the following start-up procedure.
(a) Activate power. (AC pin = “L”)
(b) Engage auto clear. (AC pin = “H”)
(c) Disable data input for a 200 m sec (time enough to allow the
internal oscillator circuit to stabilize).
(d) Set register LEVEL n.
(e) Set register PAL/NTSC.
(f) Set register PC n.
(g) Disable data input for a 20 m sec (time enough to allow the
internal oscillator circuit to stabilize).
(h) Set other registers.
(i) Set the SYRAM.
(j) Set the internal display RAM.
(k) Turn registers DSPON and DSPONV on.
4. When resuming internal oscillation from
the off state
The internal oscillator circuit stops oscillating when register LEVEL 1
= 1, DSPON = 0, DSPONV = 0 and CS pin = “H”.
When resuming internal oscillation from the off state, up until the os-
cillator circuit stabilizes, data is sometimes not set correctly in the
register. Therefore, start oscillation as follows.
(a) CS pin = “H” (Oscillation off)
(b) CS pin =“L” (Oscillation start)
(c) Wait for a 20 m sec (time enough to allow the internal oscilla-
tor circuit to stabilize).
(d) Set register LEVEL 1 = 0.
(e) Set other registers, SYRAM and internal display RAM.
(f) Turn registers DSPON and DSPONV on.
5. Other notes on oscillation
Make note of the fact that the internal oscillator circuit cannot stabi-
lize in the below situations.
(a) When the external composite video signal is discontinuous
(when changing channels, etc.)
(b) When register PC n setting is changed
(c) When register LEVEL n setting is changed
Before changing settings, turn registers DSPON and DSPONV off.
Also, disable data input for 20 m sec after making settings.
6. When no external composite video signal is in-
put
Without a signal, characters cannot be displayed by external syn-
chronization. Therefore, switch to internal synchronization.
7. When signal level of the external compos-
ite video signal is extremely poor
With a weak electric field, character display is uncontrollable by ex-
ternal synchronization. Therefore, switch to internal synchronization.
8. When a crystal oscillator is used as the IC's fsc
input
It is possible to connect a crystal oscillator between OSCIN and
OSCOUT to input the subcarrier frequency (fsc) signal to the OSCIN
pin. Talk with the manufacturer of the crystal oscillator you want to
use about matching it to this IC.
However, when using a crystal oscillator, it is not possible to super-
impose colors. Therefore, set the SCOR register (address 2B016 in
DAI register) to “0”.
Crystal oscillator frequency
NTSC system : 3.580 MHz
PAL system : 4.434 MHz
M-PAL system : 3.576 MHz
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