NS7520B-1-C36 Digi International, NS7520B-1-C36 Datasheet - Page 148

• Manufacturer Part Number: NS7520B-1-C36
• Description: IC ARM MICROPROCESSOR 177BGA
• Manufacturer: Digi International
• Series: NET+ARM®r

Specifications of NS7520B-1-C36

• Applications: Network Processor
• Core Processor: ARM7
• Program Memory Type: External Program Memory
• Controller Series: -
• Ram Size: External
• Interface: EBI/EMI, Ethernet, DMA, SPI, UART
• Number Of I /o: 16
• Voltage - Supply: 1.4 V ~ 3.6 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 177-LFBGA
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

Buffer Descriptor Pointer register
DMA Control register
1 3 6
D M A c h a n n e l r e g i s t e r s
Address: FF90 0000 / 20 / 40 / 60 / 80 / A0 / C0 / E0 / 100 / 120 / 140 / 160 / 180 / 1A0 / 1C0 / 1E0
The Buffer Descriptor Pointer register contains the address of the first buffer
descriptor in a contiguous list of descriptors.
DMA channel 1 is unique in that it supports four different buffer descriptors: A, B, C,
and D. Each buffer descriptor contains a separate ring of descriptors, and identifies a
block of data buffers with a different size. This feature allows the Ethernet receiver
to choose the optimum buffer size for the incoming packet.
Address: FF90 0010 / 30 / 50 / 70 / 90 / B0 / D0 / F0 / 110 / 130 / 150 / 170 / 190 / 1B0 / 1D0 / 1F0
Register bit assignment
Table 50: DMA Control register bit definition
D31
Bits
15
CE
15
31
31
30
30
CA
14
14
R/W
Access
N S 7 5 2 0 H a r d w a r e R e f e r e n c e , R e v G 9 / 2 0 0 7
29
13
29
13
STATE
BB
28
12
28
12
CE
Mnemonic
27
11
27
11
MODE
26
10
26
10
0
Reset
25
25
9
9
Buffer descriptor pointer
Buffer descriptor pointer
BTE
24
24
8
8
DMA channel enable
Set only after the other channel mode bits are set. The DMA
channel begins reading the first buffer descriptor when CE
is set to 1.
Description
REQ
23
23
7
7
RSVD
22
22
6
6
SINC_
21
21
5
5
INDEX
DINC_
20
20
4
4
19
19
3
3
Reserved
18
18
2
2
17
17
1
1
SIZE
16
16
0
0