
III PERIPHERAL BLOCK: SINGLE MASTER I2C-BUS
EPSON
S1C33T01 FUNCTION PART
B-III-9-26
Table 9.13
Relationship Between f
CLK and fNCLKx Due to the Noise Filter Clock (NCLKx) Divisor Register Setting
(NCLK_Px[3:0])
f
CLK
NCLK_Px
[3:0]
50,000
kHz
33,000
kHz
25,000
kHz
20,000
kHz
10,000
kHz
8,000
kHz
1/2
00
25,000kHz
16,500kHz
12,500kHz
10,000kHz
5,000kHz
4,000kHz
1/4
01
12,500kHz
8,250kHz
6,250kHz
5,000kHz
2,500kHz
2,000kHz
1/8
02
6,250kHz
4,125kHz
3,125kHz
2,500kHz
1,250kHz
1,000kHz
1/12
03
4,167kHz
2,750kHz
2,083kHz
1,667kHz
833kHz
667kHz
1/16
04
3,125kHz
2,062kHz
1,563kHz
1,250kHz
625kHz
500kHz
1/20
05
2,500kHz
1,650kHz
1,250kHz
1,000kHz
500kHz
400kHz
1/24
06
2,083kHz
1,375kHz
1,042kHz
833kHz
417kHz
333kHz
1/28
07
1,786kHz
1,178kHz
893kHz
714kHz
357kHz
286kHz
1/32
08
1,563kHz
1,031kHz
781kHz
625kHz
313kHz
250kHz
1/36
09
1,389kHz
916kHz
694kHz
555kHz
278kHz
222kHz
1/40
10
1,250kHz
825kHz
625kHz
500kHz
250kHz
200kHz
1/44
11
1,136kHz
750kHz
568kHz
455kHz
227kHz
182kHz
1/48
12
1,042kHz
687kHz
521kHz
417kHz
208kHz
166kHz
1/52
13
961kHz
634kHz
481kHz
385kHz
192kHz
153kHz
1/56
14
893kHz
589kHz
446kHz
357kHz
178kHz
142kHz
1/60
15
833kHz
550kHz
417kHz
333kHz
167kHz
133kHz
Table 9.14
Relationship Between f
NCLKx and the Generated SCLx Clock Due to the I
2C-Bus Clock (SCLx) Divisor
Register Setting (SCL_Px[2:0])
f
NCLKx
SCL_Px
[2:0]
25,000
kHz
10,000
kHz
5,000
kHz
1,000
kHz
500
kHz
250
kHz
00
6,250kHz
2,500kHz
1,250kHz
250kHz
125kHz
6kHz
01
3,125kHz
1,250kHz
625kHz
125kHz
63kHz
3kHz
02
1,563kHz
625kHz
313kHz
63kHz
31kHz
1.5kHz
03
781kHz
313kHz
156kHz
31kHz
16kHz
0.8kHz
04
391kHz
156kHz
78kHz
16kHz
8kHz
0.4kHz
05
195kHz
78kHz
39kHz
8kHz
4kHz
0.2kHz
06
98kHz
39kHz
20kHz
4kHz
2kHz
0.1kHz
07
49kHz
20kHz
10kHz
2kHz
1kHz
0.05kHz
Note: The transfer rate has a period 4 times that of the output from the SCLx prescaler.
(2) Notes on use of the output push-pull circuit
Since the outputs go to the high-impedance state when the bus is in the free state, external pull-up resistors
must be used.
In the standby state during data transfers, SCA control is cut and the line set to the high-impedance state to
prevent bus contention, even if the push-pull circuit is used.
This circuit cannot be connected to slaves that execute clock wait in bit units.
(3) SDAx I/O switching timing
SDAx I/O switching is not performed by monitoring the bus state, but rather by switching based on the time.
Since the ACK is returned to the slave after verifying the EOP from the DMA for data reception completion
when HSDMA is used, and after the IDAM counter value becomes "0" for IDMA,data reception continues even
after the DMA transfer completes.
Furthermore, transfers also continue after EOP is detected even for DMA transmit operations.
This means that applications must first verify that transfers have completed on the corresponding channel (with
the status register CMPx bit) before performing the next operation.