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CHAPTER 14
SERIAL INTERFACE SIO1
User’s Manual U12790EJ2V0UD
Figure 14-20. Busy Signal and Wait Release (When BUSY0 = 0)
(b) Strobe control option
Strobe control is a function used to synchronize data transmission/reception between the master and a
slave device. The master device outputs the strobe signal from the STB/P23 pin when 8-bit transmission/
reception has been completed. By this signal, the slave device can determine the timing of the end of
data transmission. Therefore, synchronization is established even if a bit shift occurs due to noise on
the serial clock, and transmission of the next byte is not affected by the bit shift.
To use the strobe control option, the following conditions must be satisfied.
 Bit 5 (ATE) of serial operating mode register 1 (CSIM1) is set to 1.
 Bit 2 (STRB) of the automatic data transmit/receive control register (ADTC) is set to 1.
A strobe signal is output from the STB/P23 pin for the duration of 1 clock in synchronization with the falling
of the ninth serial clock.
Figure 14-21 shows the operation timing when the strobe control option is used.
Figure 14-21. Operation Timing When Strobe Control Option Is Used
D7
D6
D5
D4
D3
D2
D1 D0
D0
D7
D6
D5
D4
D3
D2
D1
D7
D6
D5
D4
D3
D2
D1 D0
D0
D7
D6
D5
D4
D3
D2
D1
Strobe signal output
SCK1
SO1
SI1
STB
CSIIF1
SCK1
D7
SO1
SI1
D6 D5 D4 D3 D2 D1 D0
D7 D6 D5 D4 D3 D2 D1 D0
BUSY
(active high)
1.5 clocks (min.)
Busy input released
Busy input valid
Wait
If made inactive
immediately after
sampled