S5920Q Applied Micro Circuits Corporation, S5920Q Datasheet - Page 114

• 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: Mailbox Overview
Reading the PCI Incoming Mailbox:
Writing the PCI Outgoing Mailbox:
Mailbox operations for the Add-On interface are functionally identical. The following sequences are suggested for
Add-On mailbox operations using status polling (interrupts disabled):
Reading an Add-On Incoming Mailbox:
Writing an Add-On Outgoing Mailbox:
AMCC Confidential and Proprietary
1. Check Mailbox Status. Read the mailbox status register to determine if any information has been passed from
2. Read Mailbox. Read the mailbox bytes which MBEF indicates are full. This automatically resets the status bits
1. Check Mailbox Status. Read the mailbox status register to determine if information previously written to the
2. Write Mailbox. Write to the outgoing mailbox byte(s).
1. Check Mailbox Status. Read the mailbox status register to determine if any information has been passed from
2. Read Mailbox. Read the mailbox bytes which AMBEF indicates are full. This automatically resets the status
1. Check Mailbox Status. Read the mailbox status register to determine if information previously written to the
2. Write Mailbox. Write to the outgoing mailbox byte(s).
the Add-On interface.
in the MBEF and AMBEF registers.
mailbox has been read by the Add-On interface. Writes to full mailbox bytes overwrite data currently in the
mailbox (if not already read by the Add-On interface). Repeat until the byte(s) to be written are empty.
the PCI interface.
bits in the AMBEF and MBEF registers.
mailbox has been read by the PCI interface. Writes to full mailbox bytes overwrite data currently in the mailbox
(if not already read by the PCI interface). Repeat until the byte(s) to be written are empty.
MBEF
IMB
MBEF
OMB
AMBEF
AIMB
AMBEF
AOMB
Bits 31:28
Bits 31:0
Bits 15:12
Bits 31:0
Bits 15:12
Bits 31:0
Bits 31:28
Bits 31:0
If a bit is set, valid data is contained in the corresponding mailbox byte.
Mailbox data.
If a bit is set, valid data is contained in the corresponding mailbox byte
and has not been read by the Add-On.
If a bit is set, valid data is contained in the corresponding mailbox byte.
Mailbox data.
If a bit is set, valid data is contained in corresponding mailbox byte and
has not been read by the PCI bus.
Mailbox data.
Mailbox data.
Revision 1.02 – April 12, 2007
Data Book
DS1596
114