Figure 10.6A Serial Output Settings (When Using Internal Shift Clock); Figure 10.6B Serial Output Settings (When Using External Shift Clock); Operation Of Serial Output - Fujitsu F2MC-8L MB89620 Series Hardware Manual

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10.

Operation of Serial Output

The 8-bit serial I/O can perform serial output of 8-bit data synchronized with a shift
clock.
The operations of 8-bit serial I/O-1 and 8-bit serial I/O-2 are the same.
n Serial Output Operation
Serial output can operate using an internal or external shift clock. When serial output operation
is enabled, the contents of the SDR register are output to the serial data output pin (SO). Serial
input is performed at the same time.
l Internal shift clock
Figure 10.6a shows the settings required to operate serial output using an internal shift clock.

Figure 10.6a Serial Output Settings (When Using Internal Shift Clock)

Activating serial output operation outputs the contents of the SDR register to the SO pin,
synchronized with the falling edge of the selected internal shift clock. At this time, the device
being communicated with (a serial input) must be waiting for input of the external shift clock.
External shift clock
l
Figure 10.6b shows the settings required to operate serial output using an external shift clock.

Figure 10.6b Serial Output Settings (When Using External Shift Clock)

Enabling serial output operation outputs the contents of the SDR register to the SO pin,
synchronized with the falling edge of the external shift clock. When serial output completes,
reset the SDR register and enable operation (SMR: SST = "1") promptly for output of the next
data.
When the device being communicated with has completed the serial input operation (on the
rising edge), hold the external shift clock at the "H" level while waiting for the next output data
(idle state).
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CHAPTER 10 8-BIT SERIAL I/O (SERIAL I/O-1 AND SERIAL I/O-2)
Bit 7 Bit 6
SMR SIOF SIOE
SDR
Bit 7 Bit 6
DDR3
× ×
PDR4
× ×
SMR SIOF SIOE
SDR
Bit 5 Bit 4 Bit 3 Bit 2
SCKE SOE CKS1 CKS0
1 1 Other than "11"
Sets transmit data.
Bit 5 Bit 4 Bit 3 Bit 2
× × ×
× ×
1
SCKE SOE CKS1 CKS0
0 1 1
Sets transmit data.
Bit 1 Bit 0
BDS SST
1
1 : Set "1".
Bit 1 Bit 0
For 8-bit serial I/O-1
× ×
0
For 8-bit serial I/O-2
× × ×
BDS SST
1 1 : Used bit
× : Unused bit
1 : Set "1".
0 : Set "0".
MB89620 series
: Used bit