Management interface, 1 flash – Cirrus Logic CobraNet User Manual

Page 25

CobraNet Programmer’s Reference

Management Interface

DS651PM25

Management Interface

The Management Interface (MI) is the means by which the CobraNet interface is
controlled and monitored. Integral to the management interface are the MI variables. The
MI variables are read and written via the Host Management Interface (HMI) or remotely
over the audio network via SNMP. Both methods operate on the same common set of MI
variables. The CobraNet device is configured in real time as the variables are changed.

Variables may have read-only, read/write, or read/write-persistent attributes. All variables
are given an initial value at startup. The value of all variables can be read. Read/write and
Read/write-persistent variable types can be both read and written. The value of persistent
variables is saved in flash memory and the variable is restored at startup to the last value
written. See

Section 5.2 "Persistence" on page 26

for more detail on persistent variables.

All MI variables are documented in the

Section 6. "Management Interface Variable

Reference" on page 28

MI variables fall into three classes. CobraNet-specific variables allow for configuration and
monitoring of CobraNet functionality such as audio transmission and reception. A second
class of variables known as SNMP MIB-II variables provides a uniform means of
monitoring a network device. These variables are primarily concerned with performance
and configuration of the network interface and associated protocols. A third class of
product-specific variables may exist when a manufacturer makes use of SNMP extension
agent capabilities. This third class of variables is used for controlling and monitoring
product-specific features and functions.

5.1

Flash

Flash memory may be updated via TFTP or through HMI. The HMI flash memory access
mechanism allows flash contents to be read and written via the host port. This provides
functionality for the HMI similar to that which TFTP provides via the network.

The mechanism cannot allow direct access to the flash memory. Instead a request to read
or write flash is performed by supplying the flash address (

flashTAddress), byte length

(

flashTLength), transfer direction (flashTDirection), and data (bridgeTxPktBuffer). The

request is then initiated by writing to

flashTRequest.

The flash memory is a byte-wide device. On 24-bit CobraNet platforms, the transmit buffer
is comprised of 3-byte words. The mapping between the byte-wide flash data and the
wider buffer memory is as follows.

Table 8. Flash Layout, 24-bit Platforms

Middle

First Word

Byte 3

Byte 2

Byte 1

Second Word

Byte 6

Byte 5

Byte 4