
Applied Micro Circuits Corporation
6195 Lusk Blvd., San Diego, CA 92121 (619) 450-9333
6-4
PCI CONTROLLER
S5933
DEVICE SPECIFICATION
6.1
ADD-ON INCOMING MAILBOX
REGISTERS (AIMBx)
Register Names:
Add-On Incoming Mailboxes
1-4
Add-On Address Offset: 00h, 04h, 08h, 0Ch
Power-up value:
XXXXXXXXh
Attribute:
Read Only
Size:
32 bits
6.2
ADD-ON OUTGOING MAILBOX
REGISTERS (AOMBx)
Register Names:
Add-On Outgoing Mailboxes
1-4
Add-On Address Offset: 10h, 14h, 18h, 1Ch
Power-up value:
XXXXXXXXh
Attribute:
Read/Write
Size:
32 bits
6.3
ADD-ON FIFO REGISTER PORT (AFIFO)
Register Name:
Add-On FIFO Port
Add-On Address Offset: 20h
Power-up value:
XXXXXXXXh
Attribute:
Read/Write
Size:
32 bits
This location provides access to the bidirectional
FIFO. Separate registers are involved when reading
and writing to this location. Accordingly, it is not
possible to read what was written to this location.
The sequence of filling and emptying this FIFO is
established by the PCI interface interrupt control and
Status Register (Section 5.9).
The FIFO’s fullness may be observed by reading the
master control/status register, AGCSTS, described in
Section 5.8. Additionally, two signal pins are provided
which reveal whether data is available (RDEMPTY)
or space to write into the FIFO is available
(WRFULL). These signals may be used to interface
with user supplied DMA logic. Caution must be exer-
cised when using these flags for FIFO transfers in-
volving 64 bit endian conversion since the FIFO must
operate on DWORD pairs.
These four DWORD registers provide a method for
sending data, commands, or command parameters
or status to the PCI interface. Add-On write opera-
tions to these registers may be in any width (byte,
word, or DWORD). These registers may also be
read. Writing to one of these registers can optionally
cause a PCI bus interrupt (if desired) when the PCI
interrupt control/status register (Section 5.9) is prop-
erly configured.
Mailbox 4, byte 3 only exists as device pins on the
S5933 device when used with a serial nonvolatile
memory. This byte is not available if a byte-wide nv
memory is used.
These four DWORD registers provide a method for
receiving data, commands, or command parameters
from the PCI interface. Add-On read operations to
these registers may be in any width (byte, word, or
DWORD). These registers are read-only. Writes to
this address space have no effect. Reading from one
of these registers can optionally cause a PCI bus
interrupt (if desired) when the PCI interrupt control/
status register (Section 5.9) is properly configured.