Philips CEM2100/00 Service Manual page 290

14. Synchronous Serial Interface (SIO1)
14.3 Function
SIO1CR<SIOS>
SIO1SR<SIOF>
SIO1SR<SEF>
pin
SCK1
SO1 pin
SIO1SR<TXF>
SIO1SR<TXERR>
INTSIO1
interrupt
request
SIO1TDB
SIO1CR
<SIOINH>
14.3.3.2 Receive mode
Start shift
operation
A7 A6 A5 A4 A3 A2 A1 A0 B7 B6 B5 B4 B3 B2 B1 B0
A B
Writing transmit Writing transmit
data A data B
Figure 14-9 Example of Transmit Error Processingme
The receive mode is selected by writing "01B" to SIO1CR<SIOM>.
(1) Starting the receive operation
Receive mode is selected by setting "01" to SIO1CR<SIOM>. Serial clock is selected by using
SIO1CR<SCK>. Transfer direction is selected by using SIO1CR<SIODIR>.
After SIO1CR<SIOS> is set to "1", SIO1SR<SIOF> is set synchronously to "1" the falling edge of
pin.
SCK1
Synchronizing with the
the direction of the bit specified by SBI1DIR<SIODIR>.
SIO1SR<SEF> is kept in high level, between the first clock falling edge of
clock falling edge.
When 8-bit data is received, the data is transferred to SIO1RDB from shift register. INTSIO1 inter-
rupt request is generated and SIO1SR<RXF> is set to "1"
Note: In internal clock operation, when the SIO1CR<SIOS> is set to "1", the serial clock is generated
from pin after maximum 1-cycle of serial clock frequency.
SCK1
(2) During the receive operation
The SIO1SR<RXF> is cleared to "0" by reading a data from SIO1RDB.
In the internal clock operation, the serial clock stops to "H" level by an automatic-wait function
when the all of the 8-bit data has been received. Automatic-wait function is released by reading a
received data from SIO1RDB. Then, receive operation is restarted after maximum 1-cycle of serial
clock.
In external clock operation, after SIO1SR<RXF> is set to "1", the received data must be read from
SIO1RDB, before the next data shift-in operation is finished.
Start shift
operation
pin's rising edge, the data is received sequentially from SI1 pin with
SCK1
Page 168
T5CL8
Start shift
operation
Unknown
pin and eighth
SCK1