NXP Semiconductors KL25 Series - DMA Support

38.4.9 DMA support
If the DMAEN bit is cleared and the IICIE bit is set, an interrupt condition generates an
interrupt request. If the DMAEN bit is set and the IICIE bit is set, an interrupt condition
generates a DMA request instead. DMA requests are generated by the transfer complete
flag (TCF).
If the DMAEN bit is set, the only arbitration lost is to another I2C module (error), and
SCL low timeouts (error) generate CPU interrupts. All other events initiate a DMA
transfer.
NOTE
Before the last byte of master receive mode, TXAK must be set
to send a NACK after the last byte’s transfer. Therefore, the
DMA must be disabled before the last byte’s transfer.
NOTE
In 10-bit address mode transmission, the addresses to send
occupy 2-3 bytes. During this transfer period, the DMA must be
disabled because the C1 register is written to send a repeat start
or to change the transfer direction.
38.5 Initialization/application information
Module Initialization (Slave)
1. Write: Control Register 2
• to enable or disable general call
• to select 10-bit or 7-bit addressing mode
2. Write: Address Register 1 to set the slave address
3. Write: Control Register 1 to enable the I2C module and interrupts
4. Initialize RAM variables (IICEN = 1 and IICIE = 1) for transmit data
5. Initialize RAM variables used to achieve the routine shown in the following figure
Module Initialization (Master)
1. Write: Frequency Divider register to set the I2C baud rate (see example in
description of ICR)
2. Write: Control Register 1 to enable the I2C module and interrupts
3. Initialize RAM variables (IICEN = 1 and IICIE = 1) for transmit data
4. Initialize RAM variables used to achieve the routine shown in the following figure
5. Write: Control Register 1 to enable TX
Initialization/application information
KL25 Sub-Family Reference Manual, Rev. 3, September 2012
716 Freescale Semiconductor, Inc.