DR
AFT
DR
AFT
DRAFT
DR
D
RAFT
DRAFT
DRA
FT DRAF
D
RAFT DRAFT DRAFT DRAFT DRAFT D
DRAFT
D
RAFT DRA
FT DRAFT DRAFT DRAFT DRA
UM10316_0
© NXP B.V. 2008. All rights reserved.
User manual
Rev. 00.06 — 17 December 2008
394 of 571
NXP Semiconductors
UM10316
Chapter 23: LPC2xx I2C-interface
8.4 I
2
C Slave Address Register (I2C[0/1]ADR - 0xE008 200C,
0xE008 300C)
These registers are readable and writable, and is 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.
8.5 I
2
C SCL High Duty Cycle Register (I2C[0/1]SCLH - 0xE008 2010,
0xE008 3010)
8.6 I
2
C SCL Low Duty Cycle Register (I2C[0/1]SCLL - 0xE008 2014,
0xE008 3014)
8.6.1 Selecting the appropriate I
2
C data rate and duty cycle
Software must set values for the registers I2SCLH and I2SCLL to select the appropriate
data rate and duty cycle. I2SCLH defines the number of PCLK cycles for the SCL high
time, I2SCLL defines the number of PCLK cycles for the SCL low time. The peripheral I2C
clock PCLK is the base clock BASE_IVNSS_CLK. The frequency is determined by the
following formula (f
PCLK
being the frequency of PCLK):
(3)
Table 325. I
2
C Data Register ( I2C[0/1]DAT - addresses 0xE008 2008, 0xE008 3008) 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
Table 326. I
2
C Slave Address register (I2C[0/1]ADR - addresses 0xE008 200C, 0xE008 300C)
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
Table 327. I
2
C SCL High Duty Cycle register (I2C[0/1]SCLH - addresses 0xE008 2010,
0xE008 3010) bit description
Bit
Symbol
Description
Reset Value
15:0
SCLH
Count for SCL HIGH time period selection.
0x0004
Table 328. I
2
C SCL Low Duty Cycle register (I2C[0/1]SCLL - addresses 0xE008 2014,
0xE008 3014) bit description
Bit
Symbol
Description
Reset Value
15:0
SCLL
Count for SCL LOW time period selection.
0x0004
I2C
bitfrequency
f
PCLK
I2CSCLH
I2CSCLL
+
---------------------------------------------------------
=