Enhanced Direct Memory Access (eDMA)
MPC5510 Microcontroller Family Reference Manual, Rev. 1
Freescale Semiconductor
12-7
Preliminary
12.3.2
Register Descriptions
This section lists the eDMA registers in address order and describes the registers and their bit fields.
Reading reserved bits in a register will return the value of zero. Writes to reserved bits in a register will be
ignored. Reading or writing to a reserved memory location will generate a bus error.
Many of the control registers have a bit width that matches the number of channels implemented in the
module, or 16-bits in size.
12.3.2.1
eDMA Control Register (EDMA_CR)
The 32-bit EDMA_CR defines the basic operating configuration of the eDMA.
Arbitration among the channels can be configured to use a fixed priority or a round robin. In fixed-priority
arbitration, the highest priority channel requesting service is selected to execute. The priorities are
assigned by the channel priority registers (see
Section 12.3.2.15, “eDMA Channel n Priority Registers
”). In round-robin arbitration mode, the channel priorities are ignored and the channels are
cycled through, from channel 15 down to channel 0, without regard to priority.
Offset: EDM 0x0000
Access: User read/write
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
R
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
W
Reset
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
R
0
0
0
0
0
0
0
0
0
0
0
0
ERCA EDBG
W
Reset
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Figure 12-2. eDMA Control Register (EDMA_CR)
Table 12-3. EDMA_CR Field Descriptions
Field
Description
0–28, 31
Reserved.
Note: Bits 28 and 31can be read and written; however, writing has no effect other than to set or clear the
bits. Reading returns the values written to the bits.
29
ERCA
Enable Round-Robin Channel Arbitration.
0 Fixed-priority arbitration is used for channel selection.
1 Round-robin arbitration is used for channel selection.
30
EDBG
Enable Debug.
0 The assertion of the system debug control input is ignored.
1 The assertion of the system debug control input causes the eDMA to stall the start of a new channel.
Executing channels are allowed to complete. Channel execution will resume when either the system
debug control input is negated or the EDBG bit is cleared.