Renesas RX Series

R01UH0823EJ0100 Rev.1.00 Page 1122 of 1823
Jul 31, 2019
RX23W Group 35. I
2
C-bus Interface (RIICa)
35.2.3 I
2
C-bus Mode Register 1 (ICMR1)
Note 1. Rewrite the BC[2:0] bits and set the BCWP bit to 0 at the same time.
BC[2:0] Bits (Bit Counter)
These bits function as a counter that indicates the number of bits remaining to be transferred at the detection of a rising
edge on the SCL0 line. Although these bits are writable and readable, it is not necessary to access these bits under normal
conditions.
To write to these bits, specify the number of bits to be transferred plus one (data is transferred with an additional
acknowledge bit) between transferred bytes when the SCL0 line is at a low level.
The values of the BC[2:0] bits return to 000b at the end of a data transfer including the acknowledge bit or when a start
condition including a restart condition is detected.
Address(es): RIIC0.ICMR1 0008 8302h
b7 b6 b5 b4 b3 b2 b1 b0
MTWP CKS[2:0] BCWP BC[2:0]
Value after reset:
00001000
Bit Symbol Bit Name Description R/W
b2 to b0 BC[2:0] Bit Counter
b2 b0
0 0 0: 9 bits
0 0 1: 2 bits
0 1 0: 3 bits
0 1 1: 4 bits
1 0 0: 5 bits
1 0 1: 6 bits
1 1 0: 7 bits
111: 8 bits
R/W*
1
b3 BCWP BC Write Protect 0: Enables a value to be written in the BC[2:0] bits.
(This bit is read as 1.)
R/W*
1
b6 to b4 CKS[2:0] Internal Reference Clock Select Select the internal reference clock (IICφ) source for the RIIC.
b6 b4
0 0 0: PCLK/1 clock
0 0 1: PCLK/2 clock
0 1 0: PCLK/4 clock
0 1 1: PCLK/8 clock
1 0 0: PCLK/16 clock
1 0 1: PCLK/32 clock
1 1 0: PCLK/64 clock
1 1 1: PCLK/128 clock
R/W
b7 MTWP MST/TRS Write Protect 0: Disables writing to the ICCR2.MST and TRS bits.
1: Enables writing to the ICCR2.MST and TRS bits.
R/W