394
CHAPTER 18 SERIAL INTERFACE CHANNEL 0 (
µ
PD78078Y Subseries)
(f)
Wait signal (WAIT)
The wait signal is output by a slave device to inform the master device that the slave device is in wait
state due to preparing for transmitting or receiving data.
During the wait state, the slave device continues to output the wait signal by keeping the SCL pin low to
delay subsequent transfers. When the wait state is released, the master device can start the next transfer.
For the releasing operation of slave devices, refer to 18.4.5 Cautions on use of I
2
C bus mode.
Figure 18-20. Wait Signal
(a) Wait of 8 Clock Cycles
(b) Wait of 9 Clock Cycles
SCL of
master device
D2
D1
D0
ACK
D7
Output by manipulating ACKT
6
7
8
9
1
3
2
4
D6
D5
D4
Set low because slave device drives low,
though master device returns to Hi-Z state.
No wait is inserted after 9th clock cycle.
(and before master device starts next transfer.)
SCL of
slave device
SCL
SDA0 (SDA1)
SCL of
master device
Set low because slave device drives low,
though master device returns to Hi-Z state.
SCL of
slave device
SCL
D2
D1
D0
ACK
D7
Output based on the value set in ACKE in advance
6
7
8
9
2
3
D6
D5
1
SDA0 (SDA1)
Summary of Contents for PD78076
Page 2: ...2 MEMO ...
Page 12: ...12 MEMO ...
Page 48: ...48 MEMO ...
Page 64: ...64 MEMO ...
Page 82: ...82 MEMO ...
Page 100: ...100 MEMO ...
Page 130: ...130 MEMO ...
Page 180: ...180 MEMO ...
Page 222: ...222 MEMO ...
Page 248: ...248 MEMO ...
Page 288: ...288 MEMO ...
Page 308: ...308 MEMO ...
Page 364: ...364 MEMO ...
Page 494: ...494 MEMO ...
Page 526: ...526 MEMO ...
Page 544: ...544 MEMO ...
Page 558: ...558 MEMO ...
Page 580: ...580 MEMO ...
Page 596: ...596 MEMO ...
Page 598: ...598 MEMO ...
Page 626: ...626 MEMO ...