Cirrus Logic AN334 User Manual
An334, Introduction
Copyright
© Cirrus Logic, Inc. 2008
(All Rights Reserved)
CS1810xx / CS4961xx Bring-up Instructions
1. INTRODUCTION
CobraNet
®
firmware is stored in external FLASH memory which must be programmed before the CobraNet device
can become operational.
Once an initial firmware load of the FLASH is accomplished, the device will be functional. All subsequent firmware
updates can be accomplished via the network, using Cirrus-supplied tools such as CobraNet Discovery or the Py-
thon-based manufacturing script.
There are two means for accomplishing this initial firmware load:
•
Use of pre-programmed FLASH
•
Use of the CID debug interface tool
1.1
Pre-Programmed Flash Device
The simplest and most efficient approach, especially for volume production, is to pre-program the FLASH
memory before it is soldered to the circuit board.
CobraNet firmware is delivered as a 1M byte binary file (example: cm18101_2_11_6.bin). The latest firm-
ware may be downloaded from the Cirrus Logic web site at
. The firmware binary file
is an exact image of FLASH contents required to boot and operate the CobraNet chip.
A properly constructed CobraNet interface populated with a pre-programmed FLASH will, without interven-
tion, boot and function properly from initial power-up.
It is recommended that the initial firmware image to be used is the cs18100_2_11.x.bin firmware file. This
is the lowest common denominator firmware and will provide proper network functionality in ALL CobraNet-
chip-based platforms. A manufacturer can then stock only one pre-programmed chip type and then, later,
update specifically required firmware variants during the manufacturing process. FLASH will always need
to be reprogrammed in any case as part of the MAC address assignment process.
1.2
I²C
®
Interface
The chip also features an I²C
®
interface. Use of the I²C port for device bring-up requires use of:
•
I²C/Parallel interface adapter.
•
Personal Computer
•
CID software
•
CobraNet Discovery Software
The software noted above is bundled with this document and can also be downloaded from the Cirrus Logic
web site. The interface adapter can be constructed from the schematic included in this document or can be
supplied by Cirrus Logic to qualified manufacturers.
Details on using the I²C interface and support software (CID) are provided in the
section.
Use of the I²C interface to load firmware is a two-step process. CID is used to load and run a base version
of firmware in volatile RAM. Once running from RAM and operational on the network, either CobraNet Dis-
covery or the Python manufacturing script must be used to permanently load the FLASH memory with the
most current firmware version.
AN334
NOVEMBER '08
AN334REV1