Philips CEM2100/00 Service Manual page 297

SIO1CR<SIOS>
SIO1SR<SIOF>
SIO1SR<SEF>
pin output
SCK1
SO1 pin
SI1 pin
INTSIO1
interrupt
request
SIO1SR<TXF>
SIO1SR<TXERR>
A
SIO1TDB
Writing transmit
data A
SIO1SR<RXF>
SIO1RDB
SIO1CR<SIOINH>
Figure 14-15 Example of Transmit/Receive (Transmit) Error Processing
(b) Receive errors
Receive errors occur on the following situation. To protect SIO1RDB and the shift register
contents, the received data is ignored while the SIO1SR<RXERR> is "1".
Start shift Start shift
operation operation
A7 A6 A5 A4 A3 A2 A1 A0 B7 B6 B5 B4 B3 B2 B1 B0
D7 D6 D5 D4 D3 D2 D1 D0 E7 E6 E5 E4 E3 E2 E1 E0 F7 F6 F5 F4 F3 F2 F1 F0
B
Writing transmit
data B
D
Reading received
data D
• Shift operation is finished before reading out received data from SIO1RDB at
SIO1SR<RXF> is "1" in an external clock operation.
If receive error occurs, set the SIO1CR<SIOS> to "0" for reading the data that received
immediately before error occurence. And read the data from SIO1RDB. Data in shift
register (at errors occur) can be read by reading the SIO1RDB again.
When SIO1SR<RXERR> is cleared to "0" after reading the received data,
SIO1SR<RXF> is cleared to "0".
After clearing SIO1CR<SIOS> to "0", when 8-bit serial clock is input to
ceive operation is stopped. To restart the receive operation, confirm that
SIO1SR<SIOF> is cleared to "0".
If the received error occurs, set the SIO1CR<SIOINH> to "1" for stopping the receive
operation immediately. In this case, SIO1CR<SIOS>, SIO1SR register, SIO1RDB reg-
ister and SIO1TDB register are initialized.
Page 175
Start shift
operation
E
Reading received Reading received
data E data F
T5CL8
Unknown
F
pin, re-
SCK1