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UM10360_0
© NXP B.V. 2009. All rights reserved.
User manual
Rev. 00.06 — 5 June 2009
417 of 808
NXP Semiconductors
UM10360
Chapter 19: LPC17xx I2C0/1/2 interface
AAC
is the Assert Acknowledge Clear bit. Writing a 1 to this bit clears the AA bit in the
I2CONSET 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 I2CONSET
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
I2CONSET 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
I2CONSET register. Writing 0 has no effect.
8.3 I
2
C Status register (I2STAT: I
2
C0, I2C0STAT - 0x4001 C004; I
2
C1,
I2C1STAT - 0x4005 C004; I
2
C2, I2C2STAT - 0x400A 0004)
Each I
2
C Status register reflects the condition of the corresponding I
2
C interface. The I
2
C
Status register is Read-Only.
The three least significant bits are always 0. Taken as a byte, the status register contents
represent a status code. There are 26 possible status codes. When the status code is
0xF8, there is no relevant information available and the SI bit is not set. All other 25 status
codes correspond to defined I
2
C states. When any of these states entered, the SI bit will
be set. For a complete list of status codes, refer to tables from
to
8.4 I
2
C Data register (I2DAT: I
2
C0, I2C0DAT - 0x4001 C008; I
2
C1, I2C1DAT -
0x4005 C008; I
2
C2, I2C2DAT - 0x400A 0008)
This register contains the data to be transmitted or the data just received. The CPU can
read and write to this register only while it is not in the process of shifting a byte, when the
SI bit is set. Data in I2DAT remains stable as long as the SI bit is set. Data in I2DAT is
always shifted from right to left: the first bit to be transmitted is the MSB (bit 7), and after a
byte has been received, the first bit of received data is located at the MSB of I2DAT.
5
STAC
START flag Clear bit.
6
I2ENC
I
2
C interface Disable bit.
7
-
Reserved. User software should not write ones to reserved bits. The value read
from a reserved bit is not defined.
Table 365. I
2
C Control Clear register (I2CONCLR: I
2
C0, I2C0CONCLR - 0x4001 C018; I
2
C1,
I2C1CONCLR - 0x4005 C018; I
2
C2, I2C2CONCLR - 0x400A 0018) bit description
Bit Symbol
Description
Table 366. I
2
C Status register (I2STAT: I
2
C0, I2C0STAT - 0x4001 C004; I
2
C1, I2C1STAT -
0x4005 C004; I
2
C2, I2C2STAT - 0x400A 0004) bit description
Bit Symbol
Description
Reset value
2:0 -
These bits are unused and are always 0.
0
7:3 Status
These bits give the actual status information about the I
2
C interface. 0x1F
Table 367. I
2
C Data register (I2DAT: I
2
C0, I2C0DAT - 0x4001 C008; I
2
C1, I2C1DAT -
0x4005 C008; I
2
C2, I2C2DAT - 0x400A 0008) bit description
Bit Symbol
Description
Reset value
7:0 Data
This register holds data values that have been received or are to
be transmitted.
0