Philips CEM2100/00, Service Manual

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Page 180
15. Synchronous Serial Interface (SIO2)
15.3 Function
T
5CL8
15.3 Function
15.3.1 Serial clock
15.3.1.1 Clock source
The serial clock can be selected by using SIO2CR<SCK>. When the serial clock is changed, the writing
instruction to SIO2CR<SCK> should be executed while the transfer is stopped (when SIO2SR<SIOF>
“0”)
(1) Internal clock
Setting the SIO2CR<SCK> to other than “111B” outputs the clock (shown in " Table 15-1 Serial
Clock Rate (fc = 16 MHz, fs = 32.768kHz) ") as serial clock outputs from
SCK2
pin. At the before
beginning or finishing of a transfer,
SCK2
pin is kept in high level.
When writing (in the transmit mode) or reading (in the receive mode) data can not follow the serial
clock rate, an automatic-wait function is executed to stop the serial clock automatically and hold the
next shift operation until reading or writing is completed (shown in " Figure 15-2 Automatic-wait
Function (Example of transmit mode) "). The maximum time from releasing the automatic-wait
function by reading or writing a data is 1 cycle of the selected serial clock until the serial clock comes
out from
SCK2
pin.
Figure 15-2 Automatic-wait Function (Example of transmit mode)
Table 15-1 Serial Clock Rate (fc = 16 MHz, fs = 32.768kHz)
NORMAL1/2, IDLE1/2 Mode SLOW1/2, SLEEP1/2 Mode
TBTCR<DV7CK> = "0" TBTCR<DV7CK> = "1"
Serial Clock Baud Rate
SCK Serial Clock Baud Rate Serial Clock Baud Rate
000
fc/2
12
3.906 kbps
fs/2
4
2048 bps
fs/2
4
2048 bps
001
fc/2
8
62.5 kbps
fc/2
8
62.5 kbps Reserved –
010
fc/2
7
125 kbps
fc/2
7
125 kbps Reserved –
011
fc/2
6
250 kbps
fc/2
6
250 kbps Reserved –
100
fc/2
5
500 kbps
fc/2
5
500 kbps Reserved –
101
fc/2
4
1.00 Mbps
fc/2
4
1.00 Mbps Reserved –
110
fc/2
3
2.00 Mbps
fc/2
3
2.00 Mbps Reserved
A B
A0
Automatically wait
A1 B7 B6 B5 B4 B3 A2 A3 A4 A5 A6 A7 B2 B1 B0
SIO2CR<SIOS>
SO2 pin
SIO2TDB
Automatic wait is released by writing SIO2TDB
SCK2
pin output