NEC uPD78P078 - Manual (Page 348)

348
CHAPTER 17 SERIAL INTERFACE CHANNEL 0 (
µ
PD78078 SUBSERIES)
Table 17-3. Various Signals in SBI Mode (1/2)
Timing Chart Definition Signal 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 set Master
Command
signal
(CMD)
SB0 (SB1) falling edge
when SCK0 = 1
Acknowledge
signal
(ACK)
(1) ACKE = 1
(2) ACKT set
• 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
D0 READY SB0 (SB1)
D0 READY SB0 (SB1)
ACK BUSY
BUSY ACK
9
SCK0 “H”
SB0 (SB1)
“H”
SB0 (SB1)
SCK0