DR
AFT
DR
AFT
DRAFT
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D
RAFT
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FT DRAF
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UM10316_0
© NXP B.V. 2008. All rights reserved.
User manual
Rev. 00.06 — 17 December 2008
398 of 571
NXP Semiconductors
UM10316
Chapter 23: LPC2xx I2C-interface
8.10 I
2
C Slave Address registers (I2ADR0 to 3: I2C0, I2C0ADR[0, 1, 2, 3]-
0xE008 20[0C, 20, 24, 28]; I2C1, I2C1ADR[0, 1, 2, 3] - address
0xE008 30[0C, 20, 24, 28])
These registers are readable and writable and are only used when an I
2
C interface is set
to slave mode. In master mode, this register has no effect. The LSB of I2ADR is the
general call bit. When this bit is set, the general call address (0x00) is recognized.
Any of these registers which contain the bit 00x will be disabled and will not match any
address on the bus. All four registers will be cleared to this disabled state on reset.
8.11 I
2
C Mask registers (I2MASK0 to 3: I2C0, I2C0MASK[0, 1, 2, 3] -
0xE008 20[30, 34, 38, 3C]; I2C1, I2C1MASK[0, 1, 2, 3] - address
0xE008 30[30, 34, 38, 3C])
The four mask registers each contain seven active bits (7:1). Any bit in these registers
which is set to ‘1’ will cause an automatic compare on the corresponding bit of the
received address when it is compared to the I2ADDRn register associated with that mask
register. In other words, bits in an I2ADDRn register which are masked are not taken into
account in determining an address match.
On reset, all mask register bits are cleared to ‘0’.
The mask register has no effect on comparison to the general call address (“0000000”).
Bits(31:8) and bit(0) of the mask registers are unused and should not be written to. These
bits will always read back as zeros.
When an address-match interrupt occurs, the processor will have to read the data register
(I2DAT) to determine what the received address was that actually caused the match.
Table 332. I
2
C Data buffer register (I2DATA_BUFFER: I2C0, I2CDATA_BUFFER -
0xE008 202C; I2C1, I2C1DATA_BUFFER- 0xE008 302C) bit description
Bit Symbol
Description
Reset value
7:0 Data
This register holds contents of the 8 msb’s of the I2DAT shift
register.
0
Table 333. I
2
C Slave Address registers (I2ADR0 to 3: I2C0, I2C0ADR[0, 1, 2, 3]- 0xE008 20[0C,
20, 24, 28]; I2C1, I2C1ADR[0, 1, 2, 3] - address 0xE008 30[0C, 20, 24, 28]) bit
description
Bit Symbol
Description
Reset value
0
GC
General Call enable bit.
0
7:1 Address
The I
2
C device address for slave mode.
0x00