
Enhanced Direct Memory Access (eDMA)
16-32
Freescale Semiconductor
16.8.3.2
Round Robin Channel Arbitration
Channels are serviced starting with the highest channel number and rotating through to the lowest channel
number without regard to the channel priority levels
16.8.4
DMA Transfer
16.8.4.1
Single Request
To perform a simple transfer of n bytes of data with one activation, set the major loop to one
(TCD
n
_CITER = TCD
n
_BITER = 1). The data transfer begins after the channel service request is
acknowledged and the channel is selected to execute. After the transfer is complete, the
TCD
n
_CSR[DONE] bit is set and an interrupt generates if properly enabled.
For example, the following TCD entry is configured to transfer 16 bytes of data. The eDMA is
programmed for one iteration of the major loop transferring 16 bytes per iteration. The source memory has
a byte wide memory port located at 0x1000. The destination memory has a longword-wide port located at
0x2000. The address offsets are programmed in increments to match the transfer size: one byte for the
source and four bytes for the destination. The final source and destination addresses are adjusted to return
to their beginning values.
Example 16-1. Single Request DMA Transfer
TCD
n
_CITER = TCD
n
_BITER = 1
TCD
n
_NBYTES = 16
TCD
n
_SADDR = 0x1000
TCD
n
_SOFF = 1
TCD
n
_ATTR[SSIZE] = 0
TCD
n
_SLAST = -16
TCD
n
_DADDR = 0x2000
TCD
n
_DOFF = 4
TCD
n
_ATTR[DSIZE] = 2
TCD
n
_DLAST_SGA= –16
TCD
n
_CSR[INT_MAJ] = 1
TCD
n
_CSR[START] = 1 (Should be written last after all other fields have been initialized)
All other TCD
n
fields = 0
This generates the following event sequence:
1. User write to the TCD
n
_CSR[START] bit requests channel service.
2. The channel is selected by arbitration for servicing.
3. eDMA engine writes: TCD
n
_CSR[DONE] = 0, TCD
n
_CSR[START] = 0,
TCD
n
_CSR[ACTIVE] = 1.
4. eDMA engine reads: channel TCD data from local memory to internal register file.
5. The source-to-destination transfers are executed as follows:
a) Read byte from location 0x1000, read byte from location 0x1001, read byte from 0x1002, read
byte from 0x1003.
MCF5329 Reference Manual, Rev 3
Содержание MCF5329
Страница 106: ...ColdFire Core 3 32 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 126: ...Enhanced Multiply Accumulate Unit EMAC 4 20 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 148: ...Cache 5 22 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 154: ...Static RAM SRAM 6 6 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 184: ...Power Management 8 18 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 204: ...Reset Controller Module 10 8 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 220: ...System Control Module SCM 11 16 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 228: ...Crossbar Switch XBS 12 8 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 268: ...General Purpose I O Module 13 40 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 392: ...SDRAM Controller SDRAMC 18 30 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 436: ...Fast Ethernet Controller FEC 19 44 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 564: ...Liquid Crystal Display Controller LCDC 22 44 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 594: ...FlexCAN 23 30 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 678: ...Pulse Width Modulation PWM Module 26 22 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 684: ...Watchdog Timer Module 27 6 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 692: ...Programmable Interrupt Timers PIT0 PIT3 28 8 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 704: ...DMA Timers DTIM0 DTIM3 29 12 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 720: ...Queued Serial Peripheral Interface QSPI 30 16 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 754: ...UART Modules 31 34 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 770: ...I2 C Interface 32 16 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 790: ...Message Digest Hardware Accelerator MDHA 33 20 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 866: ...Debug Module 36 50 Freescale Semiconductor MCF5329 Reference Manual Rev 3...
Страница 902: ...Register Memory Map Quick Reference A 26 Freescale Semiconductor MCF5329 Reference Manual Rev 3...