UM10208_2
© NXP B.V. 2007. All rights reserved.
User manual
Rev. 02 — 1 June 2007
197 of 362
NXP Semiconductors
UM10208
Chapter 16: LPC2800 I
2
C
6.1 I
2
C Receive Register (I2RX - 0x8002 0800)
6.2 I
2
C Transmit Register (I2TX - 0x8002 0800)
If the Transmit FIFO is not full, software or a DMA channel can write to the Transmit FIFO
by writing this write-only register. This register should not be written if the Transmit FIFO is
full. This register and FIFO must also be written for master receive operations, to specify
the location of Start and Stop conditions. This register and FIFO are not used in slave
mode.
Table 216. I
2
C Receive Register (I2RX - 0x8002 0800)
Bits Description
Reset
value
7:0
If the Receive FIFO is not empty, software or a DMA channel can read the oldest
byte in the Receive FIFO from this read-only register, which removes the byte
from the FIFO. Bit 7 is the first bit received. This register should not be read if the
Receive FIFO is empty.
NA
Table 217. I
2
C Transmit Register (I2RX - 0x8002 0800)
Bits
Symbol Description
Reset
value
7:0
The byte to be sent. Used only for transmission. Bit 7 is sent first.
NA
8
If this bit is 1, the I
2
C interface will send a Start condition before sending
or receiving this byte.
9
If this bit is 1, the I
2
C interface will send a Stop condition after sending
or receiving this byte. In master mode, either this must be set for the
last byte in a frame, or bit 8 must be set for the next byte, depending on
whether a Stop or Repeated Start is desired.
31:10 -
Reserved, user software should not write ones to reserved bits. The
value read from a reserved bit is not defined.
-