R01UH0092EJ0110 Rev.1.10
Page 543 of 807
Jul 31, 2012
M16C/64C Group
25. Multi-master I
2
C-bus Interface
25.2.5
I2C0 Clock Control Register (S20)
CCR4 to CCR0 (Bit rate control bit) (b4-b0)
Assuming the CCR value (3 to 31) is the value set to bits CCR4 to CCR0, the bit rate can be
calculated using the following equation:
Refer to 25.3.1.2 “Bit Rate and Duty Cycle”
for more details.
In standard-speed clock mode,
When the CCR value is other than 5 in fast-mode,
When the CCR value is 5 in fast-mode, the bit rate is assumed to reach 400 kbps, the maximum bit
rate in fast-mode.
Do not set the CCR value from 0 to 2 regardless of the fVIIC frequency.
Rewrite bits CCR4 to CCR0 when the ES0 bit in the S1D0 register is 0 (disabled).
b7 b6 b5 b4
b1
b2
b3
I2C0 Clock Control Register
Symbol
S20
Address
02B4h
Bit Symbol
Bit Name
RW
CCR0
Reset Value
RW
b0
Function
Refer to bits CCR4 to CCR0 (Bit Rate
Control Bit) (b4 to b0) in the next page.
Bit rate control bit
CCR1
CCR2
CCR3
ACK clock bit
ACKCLK
0: No ACK clock present
1: ACK clock present
RW
RW
RW
RW
CCR4
SCL mode select bit
0: Standard-speed clock mode
1: Fast-mode
FASTMODE
RW
RW
ACKBIT
ACK bit
0: ACK is returned
1: ACK is not returned
RW
00h
Bit rate
fVIIC
8
CCR value
×
-----------------------------------------
=
100 kbps
≤
Bit rate
fVIIC
4
CCR value
×
-----------------------------------------
=
400 kbps
≤
Bit rate
fVIIC
2
CCR value
×
-----------------------------------------
fVIIC
10
--------------
=
=
400 kbps
≤
Содержание M16C Series
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