M37270MF Datasheet, PDF (82/94 Pages) Mitsubishi Electric Semiconductor – SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER with CLOSED CAPTION DECODER and ON-SCREEN DISPLAY CONTROLLER

MITSUBISHI MICROCOMPUTERS
M37270MF-XXXSP
M37270EF-XXXSP, M37270EFSP
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER with CLOSED CAPTION DECODER
and ON-SCREEN DISPLAY CONTROLLER
DISPLAY OSCILLATION CIRCUIT
The OSD oscillation circuit has a built-in clock oscillation circuits, so
that a clock for OSD can be obtained simply by connecting an LC, a
ceramic resonator, or a quartz-crystal oscillator across the pins OSC1
and OSC2. Which of the sub-clock or the OSD oscillation circuit is
selected by setting bits 5 and 4 of the clock source control register
(address 021616).
OSC1 OSC2
L
C1
C2
Fig. 95. Display oscillation circuit
AUTO-CLEAR CIRCUIT
When power source is supplied, the auto-clear function can be per-
formed by connecting the following circuit to the RESET pin.
ADDRESSING MODE
The memory access is reinforced with 17 kinds of addressing modes.
Refer to the SERIES 740 <Software> User’s Manual for details.
MACHINE INSTRUCTIONS
There are 71 machine instructions. Refer to the SERIES 740 <Soft-
ware> User’s Manual for details.
PROGRAMMING NOTES
(1) The divide ratio of the timer is 1/(n+1).
(2) Even though the BBC and BBS instructions are executed imme-
diately after the interrupt request bits are modified (by the pro-
gram), those instructions are only valid for the contents before
the modification. At least one instruction cycle is needed (such as
an NOP) between the modification of the interrupt request bits
and the execution of the BBC and BBS instructions.
(3) After the ADC and SBC instructions are executed (in decimal
mode), one instruction cycle (such as an NOP) is needed before
the SEC, CLC, or CLD instruction is executed.
(4) An NOP instruction is needed immediately after the execution of
a PLP instruction.
(5) In order to avoid noise and latch-up, connect a bypass capacitor
(≈ 0.1 µF) directly between the VCC pin–VSS pin, AVCC pin–VSS
pin, and the VCC pin–CNVSS pin using a thick wire.
Circuit example 1
Vcc
RESET
Vss
Circuit example 2
RESET
Vcc
Vss
Note : Make the level change from “L” to “H” at the point at
which the power source voltage exceeds the specified
voltage.
Fig. 96. Auto-clear circuit example
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