EM78P312N
8-Bit Microcontroller
shift start
shift start
SPI S
shift finish
shift finish
RBF
WBE
/SCK pin
SO pi n
SI pi n
b0 b1 b2 b3 b4 b5 b6 b7
d0 d1 d2 d3 d4 d5 d6 d7
a0 a1 a2 a3 a4 a5 a6 a7
c0 c1 c2 c3 c4 c5 c6 c7
SPI F
SPI D
a
c
b
d
write data
Fig. 5-16 Transmit/Receive Mode (8-bit, 1 word)
(d) Multiple Device Connect (/SS)
read data writedata
read data
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.
SDO
SDI
SCK
/SS
PP.6677
Master
P66
P 65
P65
PP6644
/SS
SCK
SDO
SDI
SDI
/SS
SCK
SDO
SDI
SDI
/SS
SCK
SDO
SDI
SDI
/SS
SCK
SDO
SDI
SDI
Slave Device 1
Slave Device 2
Slave Device 3
Slave Device 4
Fig. 5-17 The SPI Configuration Example of Single-Master and Multi-Slaves
34 •
Product Specification (V1.0) 10.03.2006
(This specification is subject to change without further notice)
ELAN [ ELAN MICROELECTRONICS CORP ]
