CobraNet Hardware User’s Manual
Host Management Interface (HMI)
7.4 Protocol and Messages
The message conduit is used to issue commands to the CS1810xx/CS4961xx and
retrieve HMI status. The data conduit is used to transfer data dependent on the HMI state
as determined by commands issued by the host via the message conduit.
7.4.1 Messages
Messages are used to efficiently invoke action in the CS1810xx/CS4961xx. To send a
message, the host optionally writes to the A, B, and C registers. Writing to the D register
transmits the message to the CS1810xx/CS4961xx. A listing of all HMI messages is
shown in Table 4. Refer also to "HMI Definitions" on page 33 and "HMI Access Code" on
page 34.
DRQ Handshake
Message
A
B
C
D
Mode
Translate Address
Acknowledge Interrupt
Identify
n/c
Address (MS)
Address
n/c
Address (LS)
0xB3
0xB4
0xB5
n/c
n/c
n/c
n/c
7
read
n/c
Goto Packet Transmit
Buffer
write
write
n/c
n/c
n/c
n/c
n/c
n/c
n/c
6
5
4
0xB5
0xB5
0xB5
Goto Translation
Acknowledge Packet
Receipt
Transmit Packet
Goto Counters
n/c
n/c
n/c
n/c
n/c
3
2
0xB5
0xB5
read
Goto Packet Receive
Buffer
read
read
n/c
n/c
n/c
n/c
1
0
0xB5
0xB5
Goto Translation
Table 4. HMI messages
28
©Copyright 2005 Cirrus Logic, Inc.
DS651UM23
Version 2.3
CIRRUS [ CIRRUS LOGIC ]
