NXP Semiconductors LPC24XX UM10237 - Manual (Page 572)

UM10237_4 © NXP B.V. 2009. All rights reserved.
User manual Rev. 04 — 26 August 2009 572 of 792
1. Basic configuration
The I 2 C0/1/2 interfaces are configured using the following registers:
1. Power: In the PCONP register ( Table 4–63 ), set bit PCI2C0/1/2.
Remark: On reset, all I 2 C interfaces are enabled (PCI2C0/1/2 = 1).
2. Clock: In PCLK_SEL0 select PCLK_I2C0; in PCLK_SEL1 select PCLK_I2C1/2 (see
Section 4–3.3.4 .
3. Pins: Select I 2 C pins and their modes in PINSEL0 to PINSEL4 and PINMODE0 to
PINMODE4 (see Section 9–5 ).
Remark: I 2 C0 pins SDA0 and SCL0 are open-drain outputs for I 2 C-bus compliance
(see Section 9–5.14 ).
4. Interrupts are enabled in the VIC using the VICIntEnable register ( Table 7–106 ).
5. Initialization: see Section 22–10.1 and Section 22–9.12.1 .
2. Features
• Standard I 2 C compliant bus interfaces that may be configured as Master, Slave, or
Master/Slave.
• Arbitration between simultaneously transmitting masters without corruption of serial
data on the bus.
• Programmable clock to allow adjustment of I 2 C transfer rates.
• Bidirectional data transfer between masters and slaves.
• Serial clock synchronization allows devices with different bit rates to communicate via
one serial bus.
• Serial clock synchronization can be used as a handshake mechanism to suspend and
resume serial transfer.
• The I 2 C bus may be used for test and diagnostic purposes.
3. Applications
Interfaces to external I 2 C standard parts, such as serial RAMs, LCDs, tone generators,
etc.
4. Description
A typical I 2 C bus configuration is shown in Figure 22–111 . Depending on the state of the
direction bit (R/W), two types of data transfers are possible on the I 2 C bus:
• Data transfer from a master transmitter to a slave receiver. The first byte transmitted
by the master is the slave address. Next follows a number of data bytes. The slave
returns an acknowledge bit after each received byte.
UM10237
Chapter 22: LPC24XX I 2 C interfaces I 2 C0/1/2
Rev. 04 — 26 August 2009 User manual