Table of Contents
Advertisement
5 PERIPHERAL CIRCUITS AND THEIR OPERATION (Serial Interface)
E0C88832/88862
SIN(P10)
SOUT(P11)
SCLK(P12)
Input port(Kxx)
(a) Clock synchronous master mode
E0C88832/88862
SIN(P10)
SOUT(P11)
SCLK(P12)
SRDY(P13)
(b) Clock synchronous slave mode
E0C88832/88862
SIN(P10)
SOUT(P11)
(c) Asynchronous 7-bit/8-bit mode
Fig. 5.7.3.1 Connection examples of serial interface I/O terminals
5.7.4 Clock source
There are four clock sources and selection is made
by setting the two bits of the clock source selection
register SCS0 and SCS1 as shown in table below.
Table 5.7.4.1 Clock source
SCS1
SCS0
1
1
1
0
0
1
0
0
Division of the synchronous clock
OSC3 oscillation frequencies
50
External
serial device
Data input
Data output
CLOCK input
READY output
External
serial device
Data input
Data output
CLOCK output
READY input
External
serial device
Data input
Data output
Clock source
Programmable timer
f
/ 4
OSC3
f
/ 8
OSC3
f
/ 16
OSC3
OSC3
oscillation
circuit
Fig. 5.7.4.1
Programmable timer 1
underflow signal
Table 5.7.4.2
Transfer rate
and transfer rates
(bps)
9,600
4,800
2,400
1,200
This register setting is invalid in clock synchronous
slave mode and the external clock input from the
SCLK terminal is used.
When the "programmable timer" is selected, the
programmable timer 1 underflow signal is divided
by 1/2 and this signal used as the clock source.
With respect to the transfer rate setting, see "5.10
Programmable Timer".
At initial reset, the synchronous clock is set to
"f
/16".
OSC3
Whichever clock is selected, the signal is further
divided by 1/16 and then used as the synchronous
clock.
Furthermore, external clock input is used as is for
SCLK in clock synchronous slave mode.
Table 5.7.4.2 shows an examples of transfer rates
and OSC3 oscillation frequencies when the clock
source is set to programmable timer.
When the demultiplied signal of the OSC3 oscilla-
tion circuit is made the clock source, it is necessary
to turn the OSC3 oscillation ON, prior to using the
serial interface.
A time interval of several 100 µsec to several 10
msec, from the turning ON of the OSC3 oscillation
circuit to until the oscillation stabilizes, is
necessary, due to the oscillation element that is
used. Consequently, you should allow an adequate
waiting time after turning ON of the OSC3
oscillation, before starting transmitting/receiving
of serial interface. (The oscillation start time will
vary somewhat depending on the oscillator and on
the externally attached parts. Refer to the oscillation
start time example indicated in Chapter 7, "ELEC-
TRICAL CHARACTERISTICS".)
At initial reset, the OSC3 oscillation circuit is set to
OFF status.
1/4
f
OSC3
1/8
Divider
1/16
1/2
(Clock synchronous slave mode)
SCLK
OSC3 oscillation frequency / Programmable timer settings
f
= 3.072 MHz
OSC3
PSC1X
RLD1X
0 (1/1)
09H
0 (1/1)
13H
0 (1/1)
27H
0 (1/1)
4FH
600
0 (1/1)
9FH
300
1 (1/4)
4FH
150
1 (1/4)
9FH
EPSON
1/16
Selector
Selector
f
= 4.608 MHz
f
OSC3
OSC3
PSC1X
RLD1X
PSC1X
0 (1/1)
0EH
0 (1/1)
0 (1/1)
1DH
0 (1/1)
0 (1/1)
3BH
0 (1/1)
0 (1/1)
77H
0 (1/1)
0 (1/1)
EFH
0 (1/1)
1 (1/4)
77H
1 (1/4)
1 (1/4)
EFH
1 (1/4)
E0C88832/88862 TECHNICAL MANUAL
Synchro-
nous clock
= 4.9152 MHz
RLD1X
0FH
1FH
3FH
7FH
FFH
7FH
FFH
Advertisement
Table of Contents
