Enhanced Direct Memory Access Controller (eDMA)
21-56
Freescale Semiconductor
PXR40 Microcontroller Reference Manual, Rev. 1
15. eDMA engine writes: EDMA
_x
_TCD.ACTIVE = 0, EDMA
_x
_TCD.DONE = 1,
EDMA_
x
_IRQR
n
= 1.
16. The channel retires
major loop complete.
The eDMA goes idle or services the next channel.
21.5.5.3
Modulo Feature
The modulo feature of the eDMA provides the ability to implement a circular data queue in which the size
of the queue is a power of two. MOD is a 5-bit bitfield for both the source and destination in the TCD and
specifies which lower address bits are allowed to increment from their original value after the
a offset calculation. All upper address bits remain the same as in the original value. A setting of 0
for this field disables the modulo feature.
shows how the transfer addresses are specified based on the setting of the MOD field. Here a
circular buffer is created where the address wraps to the original value while the 28 upper address bits
(0x1234567x) retain their original value. In this example the source address is set to 0x12345670, the
offset is set to 4 bytes and the mod field is set to 4, allowing for a 2
4
byte (16-byte) size queue.
21.5.6
TCD Status
21.5.6.1
Minor Loop Complete
There are two methods to test for minor loop completion when using software initiated service requests.
The first method is to read the EDMA
_x
_TCD.CITER field and test for a change. Another method may
be extracted from the sequence below. The second method is to test the EDMA
_x
_TCD.START bit AND
the EDMA
_x
_TCD.ACTIVE bit. The minor loop complete condition is indicated by both bits reading zero
after the EDMA
_x
_TCD.START was written to a 1. Polling the EDMA
_x
_TCD.ACTIVE bit may be
inconclusive because the active status may be missed if the channel execution is short in duration.
The TCD status bits execute the following sequence for a software activated channel:
1. EDMA
_x
_TCD.START = 1, EDMA
_x
_TCD.ACTIVE = 0, EDMA
_x
_TCD.DONE = 0 (channel
service request via software).
Table 21-25. Modulo Feature Example
Transfer
Number
Address
1
0x12345670
2
0x12345674
3
0x12345678
4
0x1234567C
5
0x12345670
6
0x12345674
Содержание PXR4030
Страница 1: ...PXR40 Microcontroller Reference Manual Devices Supported PXR4030 PXR4040 PXR40RM Rev 1 06 2011...
Страница 30: ...PXR40 Microcontroller Reference Manual Rev 1 Freescale Semiconductor xxx...
Страница 40: ...PXR40 Microcontroller Reference Manual Rev 1 xl Freescale Semiconductor...
Страница 66: ...Memory Map PXR40 Microcontroller Reference Manual Rev 1 2 4 Freescale Semiconductor...
Страница 120: ...Signal Descriptions 3 54 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 158: ...Power Management Controller PMC 5 26 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 182: ...Frequency Modulated Phase Locked Loop FMPLL 6 24 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 278: ...System Integration Unit SIU 7 96 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 280: ...System Information Module PXR40 Microcontroller Reference Manual Rev 1 8 2 Freescale Semiconductor...
Страница 300: ...Boot Assist Module BAM 9 20 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 346: ...Interrupts and Interrupt Controller INTC 10 46 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 352: ...General Purpose Static RAM SRAM 11 6 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 432: ...Core e200z7 Overview PXR40 Microcontroller Reference Manual Rev 1 13 44 Freescale Semiconductor...
Страница 460: ...Peripheral Bridge PBRIDGE 15 16 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 478: ...Memory Protection Unit MPU 16 18 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 496: ...Error Correction Status Module ECSM 17 18 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 524: ...Periodic Interrupt Timer PIT_RTI 20 12 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 740: ...FlexRay Communication Controller FLEXRAY 22 156 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 860: ...FlexCAN Module 24 50 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 928: ...Deserial Serial Peripheral Interface DSPI 25 68 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 982: ...Enhanced Serial Communication Interface eSCI 26 54 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 1114: ...Enhanced Queued Analog to Digital Converter EQADC 27 132 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 1167: ...Decimation Filter Freescale Semiconductor 28 53 PXR40 Microcontroller Reference Manual Rev 1...
Страница 1168: ...Decimation Filter 28 54 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 1262: ...Enhanced Time Processing Unit eTPU2 29 94 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...
Страница 1399: ...Nexus Development Interface NDI Freescale Semiconductor 31 83 PXR40 Microcontroller Reference Manual Rev 1...
Страница 1400: ...Nexus Development Interface NDI 31 84 Freescale Semiconductor PXR40 Microcontroller Reference Manual Rev 1...