SH7706 Datasheet, PDF (423/749 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperH™ RISC engine Family/SH7700 Series

Section 14 Serial Communication Interface (SCI)
Bit Bit Name Initial Value R/W Description
1
CKE1
0
R/W Clock Enable 1 and 0
0
CKE0
0
R/W These bits select the SCI clock source and enable or
disable clock output from the SCK pin. Depending on
the combination of CKE1 and CKE0, the SCK pin can
be used for serial clock output or serial clock input.
The CKE0 setting is valid only in the asynchronous
mode, and only when the SCI is internally clock (CKE1
= 0). The CKE0 setting is ignored in the clock
synchronous mode, or when an external clock source is
selected (CKE1 = 1). Before selecting the SCI
operating mode in the serial mode register (SCSMR),
set CKE1 and CKE0. For further details on selection of
the SCI clock source, see table 14.9.
• Asynchronous mode
00: Internal clock; SCK0 pin is used for input pin (input
signal is ignored).^*1
01: Internal clock; SCK0 pin is used for clock output.^*2
01: External clock; SCK0 pin is used for clock input.^*3
11: External clock; SCK0 pin is used for clock input.^*3
• Clock synchronous mode
00: Internal clock; SCK0 pin is used for synchronous
clock output.^*1
01: Internal clock; SCK0 pin is used for synchronous
clock output.
01: External clock; SCK0 pin is used for synchronous
clock input.
11: External clock; SCK0 pin is used for synchronous
clock input.
Notes: 1. Initial value
2. The output clock frequency is the same as
the bit rate.
3. The input clock frequency is 16 times the bit
rate.
Rev. 5.00 May 29, 2006 page 375 of 698
REJ09B0146-0500