m35060 Renesas Electronics Corporation., m35060 Datasheet - Page 29

• Manufacturer Part Number: m35060
• Description: Screen Character And Pattern Display Controllers
• Manufacturer: Renesas Electronics Corporation.

PRECAUTIONS
1. Note for when starting of system
2. When power supply noise is generated, the internal oscillator
3. Note for when throwing power supply into the M35060-XXXSP
4. Precautions when resuming internal oscillation from the OFF
5. Note for oscillation
28
Before setting registers at the starting of system, be sure to re-
set the M35060-XXXSP by applying “L” level to the AC pin.
circuit does not stabilize, whereby causing horizontal jitters
across the picture display. Therefore, connect a bypass capaci-
tor between the power supply and GND.
When power to the M35060-XXXSP is activated, characters are
sometimes output without defining the internal display RAM,
composite RAM and register. Also, immediately after power is
turned ON, up until the oscillator circuit stabilizes, data is some-
times not set correctly in the register. Therefore, use the follow-
ing start-up procedure.
(a) Throwing power supply into the M35060-XXXSP(AC pin = “ L ”)
(b) Auto-clear releasing (AC pin = “H”)
(c) 200 ms waiting state (stabilization period of internal oscillation
(d) Set register LEVELn
(e) Set register PAL/NTSC
(f) Set register PCn
(g) 20 ms waiting state (stabilization period of internal oscillation
(h) Set other registers
(i) Set SYRAM
(j) Set display RAM
(k) Set register DSPON and register DSPONV to display ON
state.
The internal oscillator circuit stops oscillating when register
LEVEL = 1, DSPON = 0, DSPONV = 0 and CS terminal = H.
When resuming internal oscillation from the OFF state, up until
the oscillator circuit stabilizes, data is sometimes not set cor-
rectly in the register. Therefore, start oscillation as follows.
(a) CS pin = “H” (oscillation stop)
(b) CS pin = “L” (oscillation start)
(c) 20 ms waiting state (stabilization period of internal oscillation
(d) Set register LEVEL 1 = 0
(e) Set other registers: SYRAM, display RAM
(f) Set register DSPON and register DSPONV to display ON
Make note of the fact that the internal oscillator circuit cannot
stabilize in the below situations.
(a)When the external composite video signal is discontinuous
(b) When change the setting of register PCn
circuit) Data input is forbidden.
circuit)
Data input is forbidden.
circuit)
(changing channels etc.)
SCREEN CHARACTER and PATTERN DISPLAY CONTROLLERS
6. When no external composite video signal is input (Without a sig-
7. When signal level of the external composite video signal is ex-
8. When a crystal oscillator is connected to OSCIN (22-pin) or
(c) When change the setting of register LEVELn
When (a)~(c), set the display to OFF by registers DSPON and
DSPONV before change the setting. Other registers’ settings are
forbidden during 20ms after the setting.
nal, characters cannot be displayed by external synchronization.
Therefore, switch to internal synchronization.)
tremely poor (With a weak electric field, character display is un-
controllable by external synchronization. Therefore, switch to
internal synchronization.)
OSCOUT (21-pin) (Talk with the manufacturer of the crystal os-
cillator you are using about matching it to this IC.)
MITSUBISHI MICROCOMPUTERS
M35060-XXXSP