M16C28 Datasheet, PDF (281/423 Pages) Renesas Technology Corp – 16-BIT SINGLE-CHIP MICROCOMPUTER M16C FAMILY / M16C/Tiny SERIES

M16C/28 Group (M16C/28, M16C/28B)
16. MULTI-MASTER I²C bus INTERFACE
Table 16.3 Setting values of S20 register and SCL frequency
Setting value of CCR4 to CCR0
SCL frequency (at VIIC=4MHz, unit : kHz) (1)
CCR4 CCR3 CCR2 CCR1 CCR0 Standard clock mode
High-speed clock mode
0
0
00
0
Setting disabled
Setting disabled
0
0
00
1
Setting disabled
Setting disabled
0
0
01
0
Setting disabled
Setting disabled
0
0
01
1
- ⁽²⁾
333
0
0
10
0
- ⁽²⁾
250
0
0
10
1
100
400 ⁽³⁾
0
0
11
0
83.3
166
500 / CCR value ⁽³⁾
1000 / CCR value ⁽³⁾
1
1
10
1
17.2
34.5
1
1
11
0
16.6
33.3
1
1
11
1
16.1
32.3
NOTES:
1. The duty of the SCL clock output is 50 %. The duty becomes 35 to 45 % only when high-speed
clock mode is selected and the CCR value = 5 (400 kHz, at VIIC = 4 MHz). “H” duration of the
clock fluctuates from –4 to +2 I²C system clock cycles in standard clock mode, and fluctuates from
–2 to +2 I²C system clock cycles in high-speed clock mode. In the case of negative fluctuation, the
frequency does not increase because the “L” is extended instead of “H” reduction. These are the
values when the SCL clock synchronization by the synchronous function is not performed. The
CCR value is the decimal notation value of the CCR4 to CCR0 bits.
2. Each value of the SCL frequency exceeds the limit at VIIC = 4 MHz or more. When using these
setting values, use VIIC = 4 MHz or less. Refer to Figure 16.6.
3. The data formula of SCL frequency is described below:
VIIC/(8 x CCR value) Standard clock mode
VIIC/(4 x CCR value) High-speed clock mode (CCR value ≠ 5)
VIIC/(2 x CCR value) High-speed clock mode (CCR value = 5)
Do not set 0 to 2 as the CCR value regardless of the VIIC frequency. Set 100 kHz (max.) in
standard clock mode and 400 kHz (max.) in high-speed clock mode to the SCL frequency by
setting the CCR4 to CCR0 bits.
Rev. 2.00 Jan. 31, 2007 ^{page 261} of 385
REJ09B0047-0200