em78p809n ELAN Microelectronics Corp, em78p809n Datasheet - Page 43

• Manufacturer Part Number: em78p809n
• Description: 8-bit Microcontroller
• Manufacturer: ELAN Microelectronics Corp

Product Specification (V1.0) 07.26.2005
(This specification is subject to change without further notice)
Slave Device 1
Fig. 18. The SPI Configuration Example of Single-Master and Multi-Slaves
/SS
SCK
Master
Master
SDO
(d) Multiple Device Connect (/SS):
When selecting external clock for transfer clock source, the /SS function can be
used. This pin (/SS) will be active when the /SS function is enabled, else the /SS
pin is a general purpose I/O. Ignore the data on the SDI and SDO pins while /SS
is high, since the SDO is no longer driven.
SDI
SDI
/SCK pin
SO pin
SI pin
SPID
SPIF
WBE
SPIS
RBF
SDO
SDI
SCK
/SS
P.67
P 65
P67
P66
P65
P 64
P64
Slave Device 2
write data
a
shift start
a0 a1 a2 a3 a4 a5 a6 a7
c0 c1 c2 c3 c4 c5 c6 c7
Fig. 17. Transmit/Receive Mode (8-bit, 1 word)
/SS
SCK
SDO
shift finish
shift finish
SDI
SDI
Slave Device 3
read data
c
/SS
b
SCK
shift start
b0 b1 b2 b3 b4 b5 b6 b7
d0 d1 d2 d3 d4 d5 d6 d7
write data
SDO
SDI
SDI
8-Bit Microcontroller
Slave Device 4
EM78P809N
/SS
SCK
read data
d
SDO
SDI
SDI
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