UM10462
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© NXP B.V. 2016. All rights reserved.
User manual
Rev. 5.5 — 21 December 2016
297 of 523
NXP Semiconductors
UM10462
Chapter 14: LPC11U3x/2x/1x I2C-bus controller
SCLL and SCLH values should not necessarily be the same. Software can set different
duty cycles on SCL by setting these two registers. For example, the I
2
C-bus specification
defines the SCL low time and high time at different values for a Fast-mode and Fast-mode
Plus I
2
C.
14.7.6 I
2
C Control Clear register (CONCLR)
The CONCLR register control clearing of bits in the CON register that controls operation
of the I
2
C interface. Writing a one to a bit of this register causes the corresponding bit in
the I
2
C control register to be cleared. Writing a zero has no effect.
AAC
is the Assert Acknowledge Clear bit. Writing a 1 to this bit clears the AA bit in the
CONSET register. Writing 0 has no effect.
SIC
is the I
2
C Interrupt Clear bit. Writing a 1 to this bit clears the SI bit in the CONSET
register. Writing 0 has no effect.
STAC
is the START flag Clear bit. Writing a 1 to this bit clears the STA bit in the CONSET
register. Writing 0 has no effect.
I
2ENC
is the I
2
C Interface Disable bit. Writing a 1 to this bit clears the I2EN bit in the
CONSET register. Writing 0 has no effect.
14.7.7 I
2
C Monitor mode control register (MMCTRL)
This register controls the Monitor mode which allows the I
2
C module to monitor traffic on
the I
2
C bus without actually participating in traffic or interfering with the I
2
C bus.
Table 277. SCLL + SCLH values for selected I
2
C clock values
I
2
C mode
I
2
C bit
frequency
I2C_PCLK (MHz)
6
8
10
12
16
20
30
40
50
SCLH + SCLL
Standard mode
100 kHz
60
80
100
120
160
200
300
400
500
Fast-mode
400 kHz
15
20
25
30
40
50
75
100
125
Fast-mode Plus
1 MHz
-
8
10
12
16
20
30
40
50
Table 278. I
2
C Control Clear register (CONCLR - 0x4000 0018) bit description
Bit
Symbol
Description
Reset
value
1:0
-
Reserved. User software should not write ones to reserved bits. The
value read from a reserved bit is not defined.
NA
2
AAC
Assert acknowledge Clear bit.
3
SIC
I
2
C interrupt Clear bit.
0
4
-
Reserved. User software should not write ones to reserved bits. The
value read from a reserved bit is not defined.
NA
5
STAC
START flag Clear bit.
0
6
I2ENC
I
2
C interface Disable bit.
0
7
-
Reserved. User software should not write ones to reserved bits. The
value read from a reserved bit is not defined.
NA
31:8 -
Reserved. The value read from a reserved bit is not defined.
-