RL78/G10 CHAPTER 12 SERIAL ARRAY UNIT
R01UH0384EJ0311 Rev. 3.11 406
Dec 22, 2016
Table 12-4. Selection of Operation Clock for Simplified I
2
C
SMR0n
Register
SPS0 Register Operation Clock (fMCK)
Note
CKS0n PRS
13
PRS
12
PRS
11
PRS
10
PRS
03
PRS
02
PRS
01
PRS
00
fCLK = 20 MHz
0 X X X X 0 0 0 0 fCLK 20 MHz
X X X X 0 0 0 1 fCLK/2 10 MHz
X X X X 0 0 1 0 fCLK/2
2
5 MHz
X X X X 0 0 1 1 fCLK/2
3
2.5 MHz
X X X X 0 1 0 0 fCLK/2
4
1.25 MHz
X X X X 0 1 0 1 fCLK/2
5
625 KHz
X X X X 0 1 1 0 fCLK/2
6
312.5 kHz
X X X X 0 1 1 1 fCLK/2
7
156.2 kHz
X X X X 1 0 0 0 fCLK/2
8
78.1 kHz
X X X X 1 0 0 1 fCLK/2
9
39.1 kHz
X X X X 1 0 1 0 fCLK/2
10
19.5 kHz
X X X X 1 0 1 1 fCLK/2
11
9.77 kHz
X X X X 1 1 0 0 fCLK/2
12
4.87 kHz
X X X X 1 1 0 1 fCLK/2
13
2.44 kHz
X X X X 1 1 1 0 fCLK/2
14
1.22 kHz
X X X X 1 1 1 1 fCLK/2
15
610 Hz
1 0 0 0 0 X X X X fCLK 20 MHz
0 0 0 1 X X X X fCLK/2 10 MHz
0 0 1 0 X X X X fCLK/2
2
5 MHz
0 0 1 1 X X X X fCLK/2
3
2.5 MHz
0 1 0 0 X X X X fCLK/2
4
1.25 MHz
0 1 0 1 X X X X fCLK/2
5
625 KHz
0 1 1 0 X X X X fCLK/2
6
312.5 KHz
0 1 1 1 X X X X fCLK/2
7
156.2 kHz
1 0 0 0 X X X X fCLK/2
8
78.1 kHz
1 0 0 1 X X X X fCLK/2
9
39.1 kHz
1 0 1 0 X X X X fCLK/2
10
19.5 kHz
1 0 1 1 X X X X fCLK/2
11
9.76 kHz
1 1 0 0 X X X X fCLK/2
12
4.87 kHz
1 1 0 1 X X X X fCLK/2
13
2.44 kHz
1 1 1 0 X X X X fCLK/2
14
1.22 kHz
1 1 1 1 X X X X fCLK/2
15
610 Hz
Note When changing the clock selected for fCLK (by changing the system clock control register (CKC) value), do so
after having stopped (serial channel stop register 0 (ST0) = 000FH) the operation of the serial array unit (SAU).
Remarks 1. X: don’t care
2. n = 0
Here is an example of setting an IIC transfer rate where f
MCK = fCLK = 20 MHz.
IIC Transfer Mode
(Desired Transfer Rate)
fCLK = 20 MHz
Operation Clock (fMCK) SDR0nH[7:1] Calculated
Transfer Rate
Error from Desired Transfer
Rate
100 kHz fCLK/2 49 100 kHz 0.0%
400 kHz fCLK 25 384.6 kHz 3.8%
Note
Note The error cannot be set to about 0% because the duty ratio of the SCL signal is 50%.
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