S5920Q Applied Micro Circuits Corporation, S5920Q Datasheet - Page 83

• Manufacturer Part Number: S5920Q
• Manufacturer: Applied Micro Circuits Corporation

Specifications of S5920Q

• Operating Temperature (min): 0C
• Operating Temperature Classification: Commercial
• Operating Temperature (max): 70C
• Package Type: PQFP
• Rad Hardened: No
• Lead Free Status / Rohs Status: Not Compliant

S5920 – PCI Product: Operation Registers
ADD-ON MAILBOX EMPTY/FULL STATUS
REGISTER (AMBEF)
Figure 32. Mailbox Empty/Full Status Register
AMCC Confidential and Proprietary
Register Name:
Add-On Address:
Power-up value:
Add-On Attribute:
Size:
31
Mailbox Empty/Full Status
34h
00000000h
Read Only
32 bits
Add-On Outgoing Mailbox Status
(RO)
28
27
0000
16
15
Reserved
This register provides empty/full visibility for each byte
within the mailboxes. The empty/full status for the
Add-On Incoming mailbox is displayed on bits 15 to 12
and the empty/full status for the Add-On Out-going
mailbox is presented on bits 31 to 28. A value of 1 sig-
nifies that a given mailbox has been written by one bus
interface but has not yet been read by the correspond-
ing destination interface. The Add-On bus incoming
mailbox is used to transfer data from the PCI bus to
the Add-On bus, and the Add-On outgoing mailbox is
used to transfer data from the Add-On bus to the PCI
bus. This register is also referred to as the PCI Mail-
box Empty/Full Status Register (MBEF).
Add-On Incoming Mailbox Status
(RO)
12
11
Revision 1.02 – April 12, 2007
0000
Data Book
Reserved
DS1596
0
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