D
S
73
4U
M
7
C
o
pyr
igh
t 20
09
C
irrus
Lo
gi
c, I
n
c
.
3
-21
SPI Port
C
S
485
xx
H
a
rd
w
a
re
U
s
er
’s
Ma
nua
l
Figure 3-17. Sample Waveform for SPI Write Functional Timing
Figure 3-18. Sample Waveform for SPI Read Functional Timing
Notes:
1.IRQ remains low until the rising edge of the clock for the last bit of the last byte to be read from the SPI slave.
2.After going high, IRQ remains high until the CS signal is raised to end the SPI transaction. If there are more bytes to read, IRQ will fall
after CS has gone high.
SCP_CLK
SCP_MOSI
Data Byte 3 (MSB)
7-bit Address
R/
W
Data Byte 2
Data Byte 1
Data Byte 0 (LSB)
SCP_CS
S C P _ C L K
S C P _ M O S I
D a t a B y t e 3 ( M S B )
7 - b i t A d d r e s s
R
/ W
D a t a B y t e 2
D a t a B y t e 1
D a t a B y t e 0 ( L S B )
S C P _ C S
S C P _ M I S O
S C P _ I R Q
