Mac addresses, Dsp conductor, Board hardware design considerations – Cirrus Logic AN335 User Manual
Page 5: An335 6. mac addresses
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6. MAC ADDRESSES
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Each CobraNet device must be assigned a unique MAC address. Cirrus Logic provides a Python script
that is used to assign unique MAC addresses. This is done via the network after valid firmware has been
loaded to FLASH. The process updates the existing firmware as well as updating the MAC address. In-
structions for downloading and installing the required Python framework as well as for use of the script
are provided by Cirrus to qualified manufacturers.
•
It is useful when using pre-programmed FLASH to preprogram the FLASH with the lowest-common-de-
nominator firmware (see
) in order to insure that the stock of FLASH chips on hand
can be used with any version CobraNet chip. Subsequent use of the Python manufacturing script is then
used to update the firmware with the correct MAC address and with the latest firmware appropriate to
the target platform.
•
MAC addresses are available from the IEEE or can be provided to qualified manufacturers by Cirrus Logic.
7. DSP CONDUCTOR™
•
This is a development tool used by manufacturers to easily create DSP code for the CS4961xx family of
devices.
•
A downloadable binary image incorporating user selected DSP functions, and based on current Cobra-
Net firmware, can be created using DSP Conductor.
•
Distribution to, or use by, end users of DSP Conductor is strictly prohibited.
•
Refer to the application note AN279 for instructions on how to control DSP functions.
•
DSP Conductor, as a development tool, loads DSP code to a target device's RAM, not to its FLASH
memory. Once the design is finished and stable, use Tools > Generate Deliverables > Patch Image… to
create a firmware file which can be downloaded to the target device's FLASH memory by using CobraNet
Discovery.
•
Refer to the PDF manual included with DSP Conductor for usage instructions
8. BOARD HARDWARE DESIGN CONSIDERATIONS
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The CM-2 design published in the appendix of the CobraNet Hardware User's Guide can be used as a
reference design. Note that this is a proven design, so deviations from this design example are strongly
discouraged.
•
It is also recommended that the design guidelines and tips presented in the “Integrating CobraNet Into
Audio Products” application note be respected.
•
Good supply bypassing, grounding and stable power supplies are essential to good performance, par-
ticularly in the areas of the MAC/PHY supply and PLL supply (1.8V analog supply on the chip). These
are particularly sensitive to stability and noise issues.
•
The following signals are required to be present / connected to the CM-2 boards in order to operate prop-
erly with the standard firmware.
–
All GND and 3.3 V supply lines connected and properly bypassed.
–
The CM-2 provides MCLK at 12.288 MHz to an external audio source/sink; which is required to
operate in slave mode and left-justified digital audio format.
–
The CM-2 provides a SCLK signal at 64 * LRCK = 3.072 MHz to an external audio source/sink,
which is required to operate in slave mode.