LPC2131/2132/2138 User Manual - mct.net

Philips Semiconductors Preliminary User Manual
ARM-based Microcontroller
SOFTWARE EXAMPLE
Initialization Routine
Example to initialize I 2 C Interface as a Slave and/or Master.
LPC2131/2132/2138
11. Load I2ADR with own Slave Address, enable general call recognition if needed.
12. Enable I2 C interrupt.
13. Write 0x44 to I2CONSET to set the I2EN and AA bits, enabling Slave functions. For Master only funcitons, write 0x40 to
I2CONSET.
Start Master Transmit Function
Begin a Master Transmit operation by setting up the buffer, pointer, and data count, then initiating a Start.
14. Initialize Master data counter.
15. Set up the Slave Address to which data will be transmitted, and add the Write bit.
16. Write 0x20 to I2CONSET to set the STA bit.
17. Set up data to be transmitted in Master Transmit buffer.
18. Initialize the Master data counter to match the length of the message being sent.
19. Exit
Start Master Receive Function
Begin a Master Receive operation by setting up the buffer, pointer, and data count, then initiating a Start.
20. Initialize Master data counter.
21. Set up the Slave Address to which data will be transmitted, and add the Read bit.
22. Write 0x20 to I2CONSET to set the STA bit.
23. Set up the Master Receive buffer.
24. Initialize the Master data counter to match the length of the message to be received.
25. Exit
I 2 C Interrupt Routine
Determine the I 2 C state and which state routine will be used to handle it.
26. Read the I2C status from I2STA.
27. Use the status value to branch to one of 26 possible state routines.
Non Mode Specific States
State : 00
Bus Error. Enter not addressed Slave mode and release bus.
28. Write 0x14 to I2CONSET to set the STO and AA bits.
29. Write 0x08 to I2CONCLR to clear the SI flag.
I2C Interfaces I2C0 and I2C1 144 November 22, 2004