PXD10RM Datasheet, PDF (461/1332 Pages) Freescale Semiconductor, Inc – PXD10 Microcontroller

Example 13-2. Configure source #5 Transmit for use with DMA Channel 2, with no periodic triggering
capability.
1. Write 0x00 to CHCONFIG2 (Base Address + 0x02)
2. Configure Channel 2 in the DMA, including enabling the channel
3. Write 0x85 to CHCONFIG2 (Base Address + 0x02)
The following code example illustrates steps #1 and #3 above:
In File registers.h:
#define DMAMUX_BASE_ADDR
0xFC084000/* Example only ! */
/* Following example assumes char is 8-bits */
volatile unsigned char *CHCONFIG0 = (volatile unsigned char *) (DMAMUX_BASE_ADDR+0x0000);
volatile unsigned char *CHCONFIG1 = (volatile unsigned char *) (DMAMUX_BASE_ADDR+0x0001);
volatile unsigned char *CHCONFIG2 = (volatile unsigned char *) (DMAMUX_BASE_ADDR+0x0002);
volatile unsigned char *CHCONFIG3 = (volatile unsigned char *) (DMAMUX_BASE_ADDR+0x0003);
volatile unsigned char *CHCONFIG4 = (volatile unsigned char *) (DMAMUX_BASE_ADDR+0x0004);
volatile unsigned char *CHCONFIG5 = (volatile unsigned char *) (DMAMUX_BASE_ADDR+0x0005);
volatile unsigned char *CHCONFIG6 = (volatile unsigned char *) (DMAMUX_BASE_ADDR+0x0006);
volatile unsigned char *CHCONFIG7 = (volatile unsigned char *) (DMAMUX_BASE_ADDR+0x0007);
volatile unsigned char *CHCONFIG8 = (volatile unsigned char *) (DMAMUX_BASE_ADDR+0x0008);
volatile unsigned char *CHCONFIG9 = (volatile unsigned char *) (DMAMUX_BASE_ADDR+0x0009);
volatile unsigned char *CHCONFIG10= (volatile unsigned char *) (DMAMUX_BASE_ADDR+0x000A);
volatile unsigned char *CHCONFIG11= (volatile unsigned char *) (DMAMUX_BASE_ADDR+0x000B);
volatile unsigned char *CHCONFIG12= (volatile unsigned char *) (DMAMUX_BASE_ADDR+0x000C);
volatile unsigned char *CHCONFIG13= (volatile unsigned char *) (DMAMUX_BASE_ADDR+0x000D);
volatile unsigned char *CHCONFIG14= (volatile unsigned char *) (DMAMUX_BASE_ADDR+0x000E);
volatile unsigned char *CHCONFIG15= (volatile unsigned char *) (DMAMUX_BASE_ADDR+0x000F);
In File main.c:
#include "registers.h"
:
:
*CHCONFIG2 = 0x00;
*CHCONFIG2 = 0x85;
Disabling a source
A particular DMA source may be disabled by not writing the corresponding source value into any of the
CHCONFIG registers. Additionally, some module specific configuration may be necessary. Please refer
to the appropriate section for more details.
Switching the source of a DMA Channel
1. Disable the DMA channel in the DMA and re-configure the channel for the new source
2. Clear the ENBL and TRIG bits of the DMA channel
3. Select the source to be routed to the DMA channel. Write to the corresponding CHCONFIG
register, ensuring that the ENBL and TRIG bits are set
Example 13-3. Switch DMA Channel 8 from source #5 transmit to source #7 transmit
1. In the DMA configuration registers, disable DMA channel 8 and re-configure it to handle the
transfers to peripheral slot 7. This example assumes channel 8 doesn’t have triggering capability.
Freescale Semiconductor
PXD10 Microcontroller Reference Manual, Rev. 1
Preliminary—Subject to Change Without Notice
13-11