at75c220 ATMEL Corporation, at75c220 Datasheet - Page 42

• Manufacturer Part Number: at75c220
• Description: Smart Internet Appliance Processor Siap
• Manufacturer: ATMEL Corporation

MAC Receive Buffer Queue Pointer
Register Name: ETH_RBQP
Access Type: Read/write
Reset Value: 0x0
•
MAC Receive Status Register
Register Name: ETH_RSR
Access Type: Read/write
Reset Value: 0x0
•
•
•
42
ADDRESS
BNA
REC
OVR
Receive buffer queue pointer. Written with the address of the start of the receive queue, reads as a pointer to the cur-
rent buffer being used. The receive buffer is forced to word alignment.
Buffer not available. An attempt was made to get a new buffer and the pointer indicated that it was owned by the pro-
cessor. The DMA will reread the pointer each time a new frame starts until a valid pointer is found. This bit will be set at
each attempt that fails even if it has not had a successful pointer read since it has been cleared. Cleared by writing a
one to this bit.
Frame received. One or more frames have been received and placed in memory. Cleared by writing a one to this bit.
RX overrun. The DMA block was unable to store the receive frame to memory, either because the ASB bus was not
granted in time or because a not OK HRESP was returned. The buffer will be recovered if this happens. Cleared by
writing a one to this bit.
31
23
15
31
23
15
7
–
–
–
7
–
30
22
14
30
22
14
6
–
–
–
6
–
AT75C220
29
21
13
29
21
13
5
–
–
–
5
–
28
20
12
28
20
12
4
–
–
–
4
–
ADDRESS
ADDRESS
ADDRESS
ADDRESS
27
19
11
27
19
11
3
–
–
–
3
–
OVR
26
18
10
26
18
10
2
–
–
–
2
REC
25
17
25
17
9
1
–
–
9
–
1
BNA
24
16
24
16
8
0
–
–
8
–
0