m37280eksp Mitsumi Electronics, Corp., m37280eksp Datasheet - Page 31

• Manufacturer Part Number: m37280eksp
• Description: Single-chip 8-bit Cmos Microcomputer With Closed Caption Decoder And On-screen Display Controller
• Manufacturer: Mitsumi Electronics, Corp.

Internal clock : The serial I/O counter is set to “7” during the write
cycle into the serial I/O register (address 0214
clock goes “H” forcibly. At each falling edge of the transfer clock after
the write cycle, serial data is output from the S
rection can be selected by bit 5 of the serial I/O mode register. At
each rising edge of the transfer clock, data is input from the S
and data in the serial I/O register is shifted 1 bit.
After the transfer clock has counted 8 times, the serial I/O counter
becomes “0” and the transfer clock stops at HIGH. At this time the
interrupt request bit is set to “1.”
Fig. 12.5.2 Serial I/O Timing (for LSB first)
Rev. 1.0
Synchronous clock
Transfer clock
Serial I/O register
write signal
Serial I/O output
Serial I/O input
Note : When an internal clock is selected, the S
S
S
OUT
IN
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER with CLOSED CAPTION DECODER
16
OUT
), and the transfer
pin. Transfer di-
OUT
M37280MF–XXXSP, M37280MK–XXXSP
pin is at high-impedance after transfer is completed.
D
0
IN
pin
D
1
External clock : The an external clock is selected as the clock source,
the interrupt request is set to “1” after the transfer clock has been
counted 8 counts. However, transfer operation does not stop, so the
clock should be controlled externally. Use the external clock of 500kHz
or less with a duty cycle of 50%.
The serial I/O timing is shown in Figure 12.5.2. When using an exter-
nal clock for transfer, the external clock must be held at HIGH for
initializing the serial I/O counter. When switching between an inter-
nal clock and an external clock, do not switch during transfer. Also,
be sure to initialize the serial I/O counter after switching.
Notes 1: On programming, note that the serial I/O counter is set by writing to
D
2
2: When an external clock is used as the synchronous clock, write trans-
the serial I/O register with the bit managing instructions, such as SEB
and CLB.
mit data to the serial I/O register when the transfer clock input level is
HIGH.
D
3
D
and ON-SCREEN DISPLAY CONTROLLER
4
MITSUBISHI MICROCOMPUTERS
D
5
Interrupt request bit is set to “1”
D
6
M37280EKSP
D
7
(Note)
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