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CHAPTER 16 SERIAL INTERFACE CHANNEL 0 (
µ
PD78054 Subseries)
<1>ACKE = 1
<2>ACKT set
Table 16-3. Various Signals in SBI Mode (1/2)
Timing ChartDefinitionSignal Name Output
Device
Output
Condition Effects on Flag Meaning of Signal
CMD signal is output
to indicate that
transmit data is an
address.
i) Transmit data is an
address after REL
signal output.
ii) REL signal is not
output and trans-
mit data is an
command.
Low-level signal to be
output to SB0 (SB1) during
one-clock period of SCK0
after completion of serial
reception
[Synchronous BUSY signal]
Low-level signal to be
output to SB0 (SB1)
following Acknowledge
signal
<1>BSYE = 0
<2>Execution of
instruction for
data write to
SIO0
(transfer start
instruction)
Master/
slave
SB0 (SB1) rising edge
when SCK0 = 1
Master
Bus release
signal
(REL)
• RELT set • RELD set
• CMDD clear
• CMDD set• CMDT setMaster
Command
signal
(CMD)
SB0 (SB1) falling edge
when SCK0 = 1
Acknowledge
signal
(ACK)
• ACKD set Completion of
reception
Slave
Busy signal
(BUSY) • BSYE = 1 —
Serial receive disable
because of
processing
—Serial receive enable
Slave
Ready signal
(READY)
High-level signal to be
output to SB0 (SB1) before
serial transfer start and
after completion of serial
transfer
[Synchronous BUSY output]
SCK0 "H"
SB0 (SB1)
"H"
SB0 (SB1)
SCK0
SCK0
D0 READY
SB0 (SB1)
D0 READY
SB0 (SB1)
ACK BUSY
BUSYACK
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