Figure 10.10A Connection Example For 8-Bit Serial I/O (Interface Between Two Mb89620S); Figure 10.10B Bidirectional Serial I/O Operation; Connection Example For 8-Bit Serial I/O - Fujitsu F2MC-8L MB89620 Series Hardware Manual

10
10.

Connection Example for 8-bit Serial I/O

This section shows an example of connecting together two MB89620 series 8-bit serial
I/O and performing bidirectional serial I/O.
n Bidirectional Serial I/O Performing

Figure 10.10a Connection Example for 8-bit Serial I/O (Interface between Two MB89620s)

Set the SI pin as the serial data input
(input port).
• Set the SCK pin as the shift clock
output
• Set the SO pin as the serial data
output
• Select an internal shift clock
• Set the data transfer (shift)
direction
NO
Serial data transfer in progress
NO
YES
MB89620 series
SO
SI
SIO-A
SCK
Internal shift clock
SIO-A
Start
Halt operation of SIO-A
(SST="0")
Is serial
transfer enabled
on SIO-B?
*1
YES
Set output data
Start serial transfer *2
(SST="1")
SIO-A
Simultaneously, SIO-B inputs data
Have 8 bits been
transferred?
*3
YES (SST="0")
Read input data
SST: The SST bit is the serial I/O transfer start bit in the serial mode register (SMR).
More data to send? *1 : If the SO, SI, and SCK pins only are connected, there is no direct method of confirming whether SIO-
NO
*2 : Data is not transferred correctly if SIO-A starts data transfer when SIO-B has not enabled serial
END *3 : An interrupt request is generated after 8-bit data have been transferred.

Figure 10.10b Bidirectional Serial I/O Operation

CHAPTER 10 8-BIT SERIAL I/O (SERIAL I/O-1 AND SERIAL I/O-2)
SI
SO
Output Input
SCK
External shift clock
Transfer enabled state
SIO-A outputs serial data
B has enabled serial transfer. Therefore, SIO-A must use a software timer or similar to delay time for
a sufficient time for SIO-B to enable serial transfer.
transfer.
SIO-B
SIO-B
Start
Halt operation of SIO-B
(SST="0")
Set the SI pin as the serial data input
(input port).
• Set the SCK pin as the shift clock
input
• Set the SO pin as the serial data
output
• Select external shift clock
• Select the same data transfer
(shift) direction as SIO-A
Set output data
Enable serial transfer
(SST="1")
SIO-B
Serial data transfer in progress
NO
Have 8 bits been
transferred?
*3
YES (SST="0")
Read input data
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