DMA Programming Model
MSC8144E Reference Manual, Rev. 3
Freescale Semiconductor
14-29
is disabled. The interrupt latency in the system must be considered as well. When you are sure
that the channel is disabled and there is no previous pending interrupts, the channel can be
activated.
14.6.5 DMA Channel Freeze Register (DMACHFR)
Setting an Sx bit freezes the corresponding channel source. Setting a Dx bit freezes the
corresponding channel destination. When a bit is set, the corresponding channel settings remain
valid and new DREQ requests are considered, but the DMA controller does not issue any
transactions to the specified channel. This register is write only; writing a 1 to a bit toggles its
value (that is, if the value is 0, it sets the bit and if it is 1, it clears the bit). Writing a zero to the
bits has no effect. The DMACHFR bits are all cleared by reset. Activating a channel clears the
corresponding DMACHFR bits (Sx and Dx). The register allows simultaneous freezing of
channels during normal operation
Note:
The DMA channels do not freeze immediately; therefore, after a channel freeze is set,
the DMA controller can issue new transactions for the channel until its pipeline is
cleared.
Note:
When the DMA channel becomes frozen, data may be left in the FIFO.
14.6.6 DMA Channel Defrost Register (DMACHDFR).
DMACHFR
DMA Channel Freeze Register
Offset 0x214
Bit
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
D15
S15
D14
S14
D13
S13
D12
S12
D11
S11
D10
S10
D9
S9
D8
S8
Type
W
Reset
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Bit
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
D7
S7
D6
S6
D5
S5
D4
S4
D3
S3
D2
S2
D1
S1
D0
S0
Type
W
Reset
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
DMACHDFR
DMA Channel Defrost Register
Offset 0x224
Bit
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
D15
S15
D14
S14
D13
S13
D12
S12
D11
S11
D10
S10
D9
S9
D8
S8
Type
W
Reset
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
Bit
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
D7
S7
D6
S6
D5
S5
D4
S4
D3
S3
D2
S2
D1
S1
D0
S0
Type
W
Reset
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
Summary of Contents for MSC8144E
Page 1: ...MSC8144E Reference Manual Quad Core Media Signal Processor MSC8144ERM Rev 3 July 2009 ...
Page 48: ...MSC8144E Reference Manual Rev 3 xlviii Freescale Semiconductor ...
Page 86: ...MSC8144E Reference Manual Rev 3 1 38 Freescale Semiconductor Overview ...
Page 168: ...MSC8144E Reference Manual Rev 3 3 60 Freescale Semiconductor External Signals ...
Page 242: ...MSC8144E Reference Manual Rev 3 5 26 Freescale Semiconductor Reset ...
Page 314: ...MSC8144E Reference Manual Rev 3 8 24 Freescale Semiconductor General Configuration Registers ...
Page 414: ...MSC8144E Reference Manual Rev 3 10 14 Freescale Semiconductor MSC8144E SC3400 DSP Subsystem ...
Page 452: ...MSC8144E Reference Manual Rev 3 11 38 Freescale Semiconductor Internal Memory Subsystem ...
Page 520: ...MSC8144E Reference Manual Rev 3 12 68 Freescale Semiconductor DDR SDRAM Memory Controller ...
Page 1070: ...MSC8144E Reference Manual Rev 3 21 28 Freescale Semiconductor Timers ...