Polarity Select Function; Lsb First/Msb First Select Function - Renesas M16C FAMILY Hardware Manual

Under development Preliminary specification
Specifications in this manual are tentative and subject to change.
R8C/11 Group

13.1.1 Polarity Select Function

Figure 13.7 shows the polarity of the transfer clock. Use the CKPOL bit in the U0C0 register to select
the transfer clock polarity.
(1) When the U0C0 register CKPOL bit = 0 (transmit data output at the falling
edge and the receive data taken in at the rising edge of the transfer clock)
0 1
CLK
T D
X 0
R D
X 0
(2) When the U0C0 register CKPOL bit = 1 (transmit data output at the rising
edge and the receive data taken in at the falling edge of the transfer clock)
0 2
CLK
T D
X 0
R D
X 0
Notes:
1. When not transferring, the CLK0 pin outputs a high signal.
2. When not transferring, the CLK0 pin outputs a low signal.
Figure 13.7 Transfer Clock Polarity

13.1.2 LSB First/MSB First Select Function

Figure 13.8 shows the transfer format. Use the UFORM bit in the U0C0 register to select the transfer
format.
(1) When U0C0 register UFORM bit = 0 (LSB first)
CLK
0
T D
X 0
R D
X 0
(2) When U0C0 register UFORM bit = 1 (MSB first)
CLK
0
T D
X 0
R D
X 0
Note: This applies to the case where the CKPOL bit in the U0C0 register
is set to "0" (transmit data output at the falling edge and the receive
data taken in at the rising edge of the transfer clock).
Figure 13.8 Transfer Format
Rev.0.91 2003 Sep 08
D0 D D D
1 2 3
D D D D
0 1 2 3
D D D D
0 1 2 3
D D D D
0 1 2 3
D0 D D D
1 2 3
D D D
D
0 1 2 3
D D D D
7 6 5 4
D D D
D 6 5 4
7
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13.1 Clock Synchronous Serial I/O Mode
D D D D
4 5 6 7
D D D D
4 5 6 7
D D D D
4 5 6 7
D D D D
4 5 6 7
D D D D
4 5 6 7
D D D D
4 5 6 7
D D D D
3 2 1 0
D D D D
3 2 1 0