
DMA Channel Multiplexer (DMA_MUX)
PXN20 Microcontroller Reference Manual, Rev. 1
Freescale Semiconductor
23-15
23.5.2.3
Disabling a Source
A particular DMA source may be disabled by not writing the corresponding source value into any of the
CHCONFIG registers. Some module specific configuration may also be necessary. Refer to the
appropriate section for more details.
23.5.2.4
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 23-3. Switch DMA Channel 8 from DSPI_A transmit to ESCI_A transmit
1. In the DMA configuration registers, disable DMA channel 8 and re-configure it to handle the
DSPI_A transmits.
2. Write 0x00 to CHCONFIG8 (base a 0x08).
3. Write 0x82 to CHCONFIG8 (base a 0x08). In this case, setting the TRIG bit has no effect
because channels 8–31 do not support the periodic triggering functionality.
The following code example illustrates steps #2 and #3 above:
In File
registers.h:
#define DMAMUX_BASE_ADDR 0xFFFDC000/* Base addr for PXN20 */
/* Following example assumes char is 8-bits */
volatile unsigned char *CHCONFIG0 = (volatile unsigned char *) (DMAMUX_BA0x0000);
volatile unsigned char *CHCONFIG1 = (volatile unsigned char *) (DMAMUX_BA0x0001);
volatile unsigned char *CHCONFIG2 = (volatile unsigned char *) (DMAMUX_BA0x0002);
volatile unsigned char *CHCONFIG3 = (volatile unsigned char *) (DMAMUX_BA0x0003);
volatile unsigned char *CHCONFIG4 = (volatile unsigned char *) (DMAMUX_BA0x0004);
volatile unsigned char *CHCONFIG5 = (volatile unsigned char *) (DMAMUX_BA0x0005);
volatile unsigned char *CHCONFIG6 = (volatile unsigned char *) (DMAMUX_BA0x0006);
volatile unsigned char *CHCONFIG7 = (volatile unsigned char *) (DMAMUX_BA0x0007);
volatile unsigned char *CHCONFIG8 = (volatile unsigned char *) (DMAMUX_BA0x0008);
volatile unsigned char *CHCONFIG9 = (volatile unsigned char *) (DMAMUX_BA0x0009);
volatile unsigned char *CHCONFIG10= (volatile unsigned char *) (DMAMUX_BA0x000A);
volatile unsigned char *CHCONFIG11= (volatile unsigned char *) (DMAMUX_BA0x000B);
volatile unsigned char *CHCONFIG12= (volatile unsigned char *) (DMAMUX_BA0x000C);
volatile unsigned char *CHCONFIG13= (volatile unsigned char *) (DMAMUX_BA0x000D);
volatile unsigned char *CHCONFIG14= (volatile unsigned char *) (DMAMUX_BA0x000E);
volatile unsigned char *CHCONFIG15= (volatile unsigned char *) (DMAMUX_BA0x000F);
volatile unsigned char *CHCONFIG16= (volatile unsigned char *) (DMAMUX_BA0x0010);
volatile unsigned char *CHCONFIG17= (volatile unsigned char *) (DMAMUX_BA0x0011);
volatile unsigned char *CHCONFIG18= (volatile unsigned char *) (DMAMUX_BA0x0012);
volatile unsigned char *CHCONFIG19= (volatile unsigned char *) (DMAMUX_BA0x0013);
volatile unsigned char *CHCONFIG20= (volatile unsigned char *) (DMAMUX_BA0x0014);
volatile unsigned char *CHCONFIG21= (volatile unsigned char *) (DMAMUX_BA0x0015);
volatile unsigned char *CHCONFIG22= (volatile unsigned char *) (DMAMUX_BA0x0016);
volatile unsigned char *CHCONFIG23= (volatile unsigned char *) (DMAMUX_BA0x0017);
volatile unsigned char *CHCONFIG24= (volatile unsigned char *) (DMAMUX_BA0x0018);
volatile unsigned char *CHCONFIG25= (volatile unsigned char *) (DMAMUX_BA0x0019);
volatile unsigned char *CHCONFIG26= (volatile unsigned char *) (DMAMUX_BA0x001A);
volatile unsigned char *CHCONFIG27= (volatile unsigned char *) (DMAMUX_BA0x001B);
Summary of Contents for PXN2020
Page 1: ...PXN20 Microcontroller Reference Manual Devices Supported PXN2020 PXN2120 PXN20RM Rev 1 06 2011...
Page 42: ...PXN20 Microcontroller Reference Manual Rev 1 lxiv Freescale Semiconductor...
Page 64: ...Introduction PXN20 Microcontroller Reference Manual Rev 1 1 22 Freescale Semiconductor...
Page 112: ...Signal Description PXN20 Microcontroller Reference Manual Rev 1 3 44 Freescale Semiconductor...
Page 118: ...Resets PXN20 Microcontroller Reference Manual Rev 1 4 6 Freescale Semiconductor...
Page 372: ...e200z6 Core Z6 PXN20 Microcontroller Reference Manual Rev 1 13 8 Freescale Semiconductor...
Page 412: ...e200z0 Core Z0 PXN20 Microcontroller Reference Manual Rev 1 14 14 Freescale Semiconductor...
Page 821: ...Media Local Bus MLB PXN20 Microcontroller Reference Manual Rev 1 Freescale Semiconductor 27 49...
Page 822: ...Media Local Bus MLB PXN20 Microcontroller Reference Manual Rev 1 27 50 Freescale Semiconductor...
Page 1376: ...Memory Map PXN20 Microcontroller Reference Manual Rev 1 A 118 Freescale Semiconductor...