
R8C/14 Group, R8C/15 Group 15. Clock Synchronous Serial I/O with Chip Select (SSU)
Rev.2.10 Jan 19, 2006 Page 151 of 253
REJ09B0164-0210
15.2 SS Shift Register (SSTRSR)
The SSTRSR register is the shift register to transmit and receive the serial data.
When the transmit data is transferred from the SSTDR register to the SSTRSR register and the MLS bit
in the SSMR register is set to “0” (MSB-first), the bit 0 in the SSTDR register is transferred to the bit 0 in
the SSTRSR register. When the MLS bit is set to “1” (LSB-first), the bit 7 in the SSTDR register is
transferred to the bit 0 in the SSTRSR register.
15.2.1 Association between Data I/O Pin and SS Shift Register
Connecting association between the data I/O pin and SSTRSR register (SS shift register) changes
according to a combination of the MSS bit in the SSCRH register and the SSUMS bit in the SSMR2
register. Also, connecting association changes according to the BIDE bit in the SSMR2 register.
Figure 15.10 shows a Connecting Association between Data I/O Pin and SSTRSR Register.
Figure 15.10 Connecting Association between Data I/O Pin and SSTRSR Register
SSTRSR Register
SSO
SSI
• When SSUMS=0
(clock synchronous communication mode)
SSTRSR Register
SSO
SSI
• When SSUMS=1 (4-wire bus communication mode),
BIDE=0 (standard mode) and MSS=0 (operates as
slave device)
SSTRSR Register
SSO
SSI
• When SSUMS=1 (4-wire bus communication mode),
BIDE=0 (standard mode) and MSS=1 (operates as
master device)
SSTRSR Register
SSO
SSI
• When SSUMS=1 (4-wire bus communication mode),
BIDE=1 (bidirectional mode)
Kommentare zu diesen Handbüchern