hd64338023s Renesas Electronics Corporation., hd64338023s Datasheet - Page 382

• Manufacturer Part Number: hd64338023s
• Description: Renesas 8-bit Single-chip Microcomputer Super Low Power Series
• Manufacturer: Renesas Electronics Corporation.

Section 10 Serial Communication Interface
Bits 1 and 0—Clock Select 1, 0 (CKS1, CKS0)
Bits 1 and 0 choose φ/64, φ/16, φw/2, or φ as the clock source for the baud rate generator.
For the relation between the clock source, bit rate register setting, and baud rate, see section
10.2.8, Bit rate register (BRR).
Bit 1
CKS1
0
0
1
1
Notes: 1. φ w/2 clock in active (medium-speed/high-speed) mode and sleep mode
10.2.6
SCR3 is an 8-bit register for selecting transmit or receive operation, the asynchronous mode clock
output, interrupt request enabling or disabling, and the transmit/receive clock source.
SCR3 can be read or written by the CPU at any time.
SCR3 is initialized to H'00 upon reset, and in standby, module standby or watch mode.
Bit 7—Transmit Interrupt Enable (TIE)
Bit 7 selects enabling or disabling of the transmit data empty interrupt request (TXI) when
transmit data is transferred from the transmit data register (TDR) to the transmit shift register
(TSR), and bit TDRE in the serial status register (SSR) is set to 1.
TXI can be released by clearing bit TDRE or bit TIE to 0.
Rev. 7.00 Mar 10, 2005 page 340 of 652
REJ09B0042-0700
Bit
Initial value
Read/Write
2. φ w clock in subactive mode and subsleep mode. In subactive or subsleep mode, SCI3
Serial Control Register 3 (SCR3)
can be operated when CPU clock is φw/2 only.
Bit 0
CKS0
0
1
0
1
R/W
TIE
7
0
Description
φ clock
φ w/2 clock *
φ/16 clock
φ/64 clock
R/W
RIE
6
0
1
/φ w clock *
R/W
TE
5
0
2
R/W
RE
4
0
MPIE
R/W
3
0
TEIE
R/W
2
0
CKE1
R/W
1
0
(initial value)
CKE0
R/W
0
0