NEC 78K0 Series User Manual page 422

(5) IIC function expansion register 0 (IICX0)
This register sets the function expansion of I
IICX0 is set by a 1-bit or 8-bit memory manipulation instruction. The CLX0 bit is set in combination with bits 3,
1, and 0 (SMC0, CL01, and CL00) of IIC clock selection register 0 (IICCL0) (see 17.3 (6) I
setting method).
Set IICX0 while bit 7 (IICE0) of IIC control register 0 (IICC0) is 0.
Reset signal generation sets IICX0 to 00H.
Figure 17-9. Format of IIC Function Expansion Register 0 (IICX0)
Address: FFA9H
Symbol 7
IICX0 0
2
(6) I C transfer clock setting method
2
The I C transfer clock frequency (f
= 1/(m × T + t
f
SCL
m = 12, 18, 24, 44, 66, 86 (see Table 17-2 Selection Clock Setting)
T: 1/f
W
t : SCL0 rise time
R
t : SCL0 fall time
F
422
CHAPTER 17 SERIAL INTERFACE IIC0
2
C.
After reset: 00H R/W
6 5
0 0
) is calculated using the following expression.
SCL
+ t )
R F
Preliminary User's Manual U17260EJ3V1UD
4 3 2
0 0 0
2
C transfer clock
1 <0>
0 CLX0