PXR40RM Datasheet, PDF (579/1434 Pages) Freescale Semiconductor, Inc – PXR40 Microcontroller

Enhanced Direct Memory Access Controller (eDMA)
All other TCD fields = 0
This generates the following sequence of events:
1. First hardware (eDMA peripheral request) request for channel service.
2. The channel is selected by arbitration for servicing.
3. eDMA engine writes: EDMA_x_TCD.DONE = 0, EDMA_x_TCD.START = 0,
EDMA_x_TCD.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(0x1000), read_byte(0x1001), read_byte(0x1002), read_byte(0x1003)
b) write_word(0x2000)  first iteration of the minor loop
c) read_byte(0x1004), read_byte(0x1005), read_byte(0x1006), read_byte(0x1007)
d) write_word(0x2004)  second iteration of the minor loop
e) read_byte(0x1008), read_byte(0x1009), read_byte(0x100a), read_byte(0x100b)
f) write_word(0x2008)  third iteration of the minor loop
g) read_byte(0x100c), read_byte(0x100d), read_byte(0x100e), read_byte(0x100f)
h) write_word(0x200c)  last iteration of the minor loop
6. eDMA engine writes: EDMA_x_TCD.SADDR = 0x1010, EDMA_x_TCD.DADDR = 0x2010,
EDMA_x_TCD.CITER = 1.
7. eDMA engine writes: EDMA_x_TCD.ACTIVE = 0.
8. The channel retires  one iteration of the major loop.
The eDMA goes idle or services the next channel.
9. Second hardware (eDMA peripheral request) requests channel service.
10. The channel is selected by arbitration for servicing.
11. eDMA engine writes: EDMA_x_TCD.DONE = 0, EDMA_x_TCD.START = 0,
EDMA_x_TCD.ACTIVE = 1.
12. eDMA engine reads: channel TCD data from local memory to internal register file.
13. The source to destination transfers are executed as follows:
a) read_byte(0x1010), read_byte(0x1011), read_byte(0x1012), read_byte(0x1013)
b) write_word(0x2010)  first iteration of the minor loop
c) read_byte(0x1014), read_byte(0x1015), read_byte(0x1016), read_byte(0x1017)
d) write_word(0x2014)  second iteration of the minor loop
e) read_byte(0x1018), read_byte(0x1019), read_byte(0x101a), read_byte(0x101b)
f) write_word(0x2018)  third iteration of the minor loop
g) read_byte(0x101c), read_byte(0x101d), read_byte(0x101e), read_byte(0x101f)
h) write_word(0x201c)  last iteration of the minor loop  major loop complete
14. eDMA engine writes: EDMA_x_TCD.SADDR = 0x1000, EDMA_x_TCD.DADDR = 0x2000,
EDMA_x_TCD.CITER = 2 (EDMA_x_TCD.BITER).
Freescale Semiconductor
PXR40 Microcontroller Reference Manual, Rev. 1
21-55