RM0316 Datasheet, PDF (281/1141 Pages) STMicroelectronics – This reference manual targets application developers

RM0316
Direct memory access controller (DMA)
13.5.4
DMA channel x number of data register (DMA_CNDTRx) (x = 1..7,
where x = channel number)
Address offset: 0x0C + 0d20 × (channel number – 1)
Reset value: 0x0000 0000
31
Res.
30
Res.
29
Res.
28
Res.
27
Res.
26
Res.
25
Res.
24
Res.
23
Res.
22
Res.
21
Res.
20
Res.
19
Res.
18
Res.
17
Res.
16
Res.
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
NDT[15:0]
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Bits 31:16 Reserved, must be kept at reset value.
Bits 15:0 NDT[15:0]: Number of data to transfer
Number of data to be transferred (0 up to 65535). This register can only be written when the
channel is disabled. Once the channel is enabled, this register is read-only, indicating the
remaining bytes to be transmitted. This register decrements after each DMA transfer.
Once the transfer is completed, this register can either stay at zero or be reloaded
automatically by the value previously programmed if the channel is configured in auto-reload
mode.
If this register is zero, no transaction can be served whether the channel is enabled or not.
13.5.5
DMA channel x peripheral address register (DMA_CPARx) (x = 1..7,
where x = channel number)
Address offset: 0x10 + 0d20 × (channel number – 1)
Reset value: 0x0000 0000
This register must not be written when the channel is enabled.
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
PA [31:16]
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15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
PA [15:0]
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Bits 31:0 PA[31:0]: Peripheral address
Base address of the peripheral data register from/to which the data will be read/written.
When PSIZE is 01 (16-bit), the PA[0] bit is ignored. Access is automatically aligned to a half-
word address.
When PSIZE is 10 (32-bit), PA[1:0] are ignored. Access is automatically aligned to a word
address.
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