M38197MA Datasheet, PDF (28/60 Pages) Mitsubishi Electric Semiconductor – SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER

MITSUBISHI MICROCOMPUTERS
3819 Group
SINGLE-CHIP 8-BIT CMOS MICROCOMPUTER
(2.3) When Selecting the Internal Clock
When selecting the internal clock, the P67/SRDY1/CS/SCLK12 pin
can be used as the SRDY1 pin by setting SC14 to “1”.
When selecting the internal clock, the P67 pin can be used as the
synchronous clock output pin SCLK12 by setting SIOAC3 to “1”. In
this case, the SCLK11 pin goes to high impedance state.
Select the function of the P67/SRDY1/CS/SCLK12 and P66/SCLK11
with the following registers (refer to Table GA-1):
qthe bit 3 (SC13), the bit 4(SC14), and the bit 6(SC16) of the se-
rial I/O1 control register
qthe bit 3 (SIOAC3) of the serial I/O automatic transfer control
register
When using both the SCLK11 and SCKL12 by switching, switch the
P67/SRDY1/CS/SCLK12 to the P67 (SC14=0) and set the P67 direc-
tion register to input mode. Note that switch SIOAC3 during “H” of
transfer clock at the completion of automatic transfer.
Table GA-1. SCLK11 and SCLK12 selection
SC16
1
SC14
0
SC33
1
SIOAC3
0
1
P66/SCLK11 P67/SCLK12
SCLK11
P67
High
impedance ^SCLK12
Note : SC13: Serial I/O1 port selection bit
SC14: SRDY1 output selection bit
SC16: Synchronous clock selection bit
SIOAC3: Synchronous clock output pin selection bit
Bit 1 write signal of serial I/O
automatic transfer control
register
Bit 1 of serial I/O automatic
transfer control register
Write signal from RAM to
serial I/O1 register
Write signal from serial I/O1
register to RAM
Data pointer
Transfer clock
(internal or SCLK output)
Receive
enabled signal
SRDY
Serial I/O output
Sout
Serial I/O input
SIN
n
DO0 DO1 DO2 DO3 DO4 DO5 DO6 DO7
DI0 DI1 DI2 DI3 DI4 DI5 DI6 DI7
n-1
DO0
DI0
Transfer interval
Fig. GA-8 Timing diagram during serial I/O automatic transfer (internal clock selected, SRDY used)
0
DO6 DO7
DI6 DI7
Bit 1 write signal of serial I/O
automatic transfer control
register
Bit 1 of serial I/O automatic
transfer control register
Write signal from RAM to
serial I/O1 register
Write signal from serial I/O1
register to RAM
Data pointer
m
Bit 3 of serial I/O automatic
transfer control register
Transfer clock
(internal)
m-1
0
n
SCLK11 output
SCLK12 output
Serial I/O output
Sout
Serial I/O input
SIN
DO0 DO1 DO2 DO3 DO4 DO5 DO6 DO7
DI0 DI1 DI2 DI3 DI4 DI5 DI6 DI
7
DO0
DI0
DO6 DO7
DI6 DI7
Transfer interval
Fig. GA-9 Timing during serial I/O automatic transfer (internal clock selected, SCLK11 and SCLK12 used)
DO0 DO1 DO2 DO3
DI0 DI1 DI2 DI
3
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