UM10360 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved.
User manual Rev. 3 — 19 December 2013 467 of 841
NXP Semiconductors
UM10360
Chapter 19: LPC176x/5x I2C0/1/2
19.10 Software example
19.10.1 Initialization routine
Example to initialize I
2
C Interface as a Slave and/or Master.
1. Load the I2ADR registers and I2MASK registers with values to configure the own
Slave Address, enable General Call recognition if needed.
2. Enable I
2
C interrupt.
3. Write 0x44 to I2CONSET to set the I2EN and AA bits, enabling Slave functions. For
Master only functions, write 0x40 to I2CONSET.
19.10.2 Start Master Transmit function
Begin a Master Transmit operation by setting up the buffer, pointer, and data count, then
initiating a START.
1. Initialize Master data counter.
2. Set up the Slave Address to which data will be transmitted, and add the Write bit.
3. Write 0x20 to I2CONSET to set the STA bit.
4. Set up data to be transmitted in Master Transmit buffer.
5. Initialize the Master data counter to match the length of the message being sent.
6. Exit
19.10.3 Start Master Receive function
Begin a Master Receive operation by setting up the buffer, pointer, and data count, then
initiating a START.
1. Initialize Master data counter.
2. Set up the Slave Address to which data will be transmitted, and add the Read bit.
3. Write 0x20 to I2CONSET to set the STA bit.
4. Set up the Master Receive buffer.
5. Initialize the Master data counter to match the length of the message to be received.
6. Exit
19.10.4 I
2
C interrupt routine
Determine the I
2
C state and which state routine will be used to handle it.
1. Read the I
2
C status from I2STA.
2. Use the status value to branch to one of 26 possible state routines.
19.10.5 Non mode specific states
19.10.5.1 State: 0x00
Bus Error. Enter not addressed Slave mode and release bus.
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