UPD784026 Renesas Electronics Corporation., UPD784026 Datasheet - Page 509

• Manufacturer Part Number: UPD784026
• Description: 16/8-bit Single-chip Microcontrollers
• Manufacturer: Renesas Electronics Corporation.

Acknowledge
signal
(ACK)
Busy signal
(BUSY)
Ready signal
(READY)
* For data transmission/reception, when the BUSY state is set, the transfer starts after transition to the READY state.
Signal Name
Outputting
Master/
Device
slave
Slave
Slave
Low-level signal
output to SB0 in
1 SCK0 clock
interval after
serial receive
completion
Low-level signal
output to SB0
after
acknowledge
signal
High-level signal
output to SB0
before start or
after completion
of serial transfer.
Definition
SCK0
SB0
SB0
D0 ACK
D0
Table 17-1 Signals in SBI Mode (2/3)
9
Timing Chart
ACK
BUSY
BUSY
READY
READY
Output Conditions
<1> ACKE = 1
<2> ACKT set
<1> BSYE = 0
<2> Data write
to SIO when
CTXE = 1 (serial
transfer start
directive)*
<3> Execution
of instruction to
read data from
SIO when CTXE
= 0 and CRXE
= 1
<4> Change of
CRXE bit from
0 to 1
• BSYE = 1
• ACKD set
Effect on Flags
—
—
Receive completed
Serial transmission/
reception not
possible because
processing is in
progress.
Serial transmission/
reception possible
Meaning of Signal