M37212 Mitsubishi, M37212 Datasheet - Page 28

• Manufacturer Part Number: M37212
• Description: SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER for VOLTAGE SYNTHESIZER
• Manufacturer: Mitsubishi

Internal clock : The serial I/O counter is set to “7” during the write
cycle into the serial I/O register (address 00DD
clock goes HIGH forcibly. At each falling edge of the transfer clock
after the write cycle, serial data is output from the S
direction 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. 8.5.2 Serial I/O Timing (for LSB first)
28
S y n c h r o n o u s c l o c k
T r a n s f e r c l o c k
S e r i a l I / O r e g i s t e r
w r i t e s i g n a l
S e r i a l I / O o u t p u t
S e r i a l I / O i n p u t
N o t e : W h e n a n i n t e r n a l c l o c k i s s e l e c t e d , t h e S
S
S
O U T
I N
M37212M4/M8–XXXSP, M37212M6–XXXSP/FP
16
), and the transfer
OUT
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER for VOLTAGE SYNTHESIZER
O U T
pin. Transfer
p i n i s a t h i g h - i m p e d a n c e a f t e r t r a n s f e r i s c o m p l e t e d .
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 1 MHz
or less with a duty cycle of 50%.
The serial I/O timing is shown in Figure 8.5.2. 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
with ON-SCREEN DISPLAY CONTROLLER
4
MITSUBISHI MICROCOMPUTERS
D
5
I n t e r r u p t r e q u e s t b i t i s s e t t o “ 1 ”
M37212EFSP/FP
D
6
D
7
( S e e n o t e )
Rev. 1.0