M37221M6_03 Datasheet, PDF (52/62 Pages) Renesas Technology Corp – SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER for VOLTAGE SYNTHESIZER with ON-SCREEN DISPLAY CONTROLLER

MITSUBISHI MICROCOMPUTERS
M37221M6-XXXSP
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER for VOLTAGE SYNTHESIZER
with ON-SCREEN DISPLAY CONTROLLER
DISPLAY OSCILLATION CIRCUIT
The CRT display clock oscillation circuit has a built-in clock oscilla-
tion circuits, so that a clock for CRT display can be obtained simply
by connecting an LC, an RC, a ceramic resonator or a quartz-crystal
oscillator circuit across the pins OSC 1 and OSC 2. Select the clock
for display with bits 0 and 1 of the CRT clock selection register (ad-
dress 00ED16).
OSC1 OSC2
L
C1
C2
Fig. 57. 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.
Circuit example 1
Vcc
RESET
Vss
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 and the VCC pin–
CNVSS pin using a thick wire.
DATA REQUIRED FOR MASK ORDERS
The following are necessary when ordering a mask ROM produc-
tion:
(1) Mask ROM Order Confirmation Form
(2) Mark Specification Form
(3) Data to be written to ROM, in EPROM form (32-pin DIP type
27C101 three identical copies)
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. 58. Auto-clear circuit example
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