Renesas SH7781 - Manual (Page 1158)

22. Serial I/O with FIFO (SIOF)
Rev.1.00 Jan. 10, 2008 Page 1128 of 1658
REJ09B0261-0100
22.4 Operation
22.4.1 Serial Clocks
(1)
Master/Slave Modes
The following two modes are available as the SIOF clock mode.
• Slave mode: SIOF_SCK, SIOF_SYNC input
• Master mode: SIOF_SCK, SIOF_SYNC output
(2) Baud Rate Generator
In SIOF master mode, the baud rate generator (BRG) is used to generate the serial clock. The baud
rate generator consists of the prescaler that can select 32 types of division ratio from 1 to 1/32 with
the BRPS4 to BRSP0 bits in SISCR and divider that can select the division ratio from 1, 1/2, 1/4,
1/8, 1/16, and 1/32. The division ratio of the baud rate generator ranges from 1 to 1/1024 of the
product of the division ratios of the prescaler and the divider.
When the master clock is not divided by the baud rate generator (the division ratio is 1), set the
MSIMM bit in SISCR to 1 and use the master clock without division as a serial clock.
Figure 22.2 shows connections for supply of the serial clock.
Baud rate generator
Prescaler Divider
MCLK
1/1 to 1/1024 MCLK
Timing control
SCKE
Master
SIOF_SCK
SIOF_MCLK
Pck
Figure 22.2 Serial Clock Supply