FINE TUNING AN EMBEDDED IDEA

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FINE–TUNING AN EMBEDDED IDEA

Applications Part 2: Ethernet-Equipped RabbitCore Modules
by Fred Eady

Start ı The Networking Core ı Code Names and Comedy ı Where and Why ı Completing Initialization • Down to Business ı Now What? ı Sources and PDF

NOW WHAT?

The next step is up to the application. If TCP/IP communications are to be established, the socket services of Dynamic C Premier use the RTL8019AS you just initialized to pass packets over an Ethernet or the Internet. Photo 2 is a STDIO window shot of what happened after I ran the sock_init function following the hardware init process I just described. Youıll see some values that will be familiar to you. The Boundary and Page Start values are set at 0x46, just where the code put them. Page Stop is registering 0x60. Our bogus ı9346 read put 0x30 in the RTL8019AS LED control register CONFIG3. Although you never really saw the MAC address, itıs sitting pretty in the PARX registers and judging by the identical values in the CURR and BNRY registers, I caught this register listing before any packets were received.

Photo 2ıThis window was generated using a function in the Realtek Dynamic C Premier library called prt_nicreg. I simply inserted the function call before a call to sock_init. The prt_nicreg function is handy for those of you who donıt have access to a Sniffer. You can insert this call anywhere you wish to examine the contents of the RTL8019AS registers.

Iıve written lots of articles describing Z-World and Rabbit Semiconductor hardware. The idea behind this walk through microcode land was to show you how you too can use the resources of the Dynamic C Premier source code to your advantage. I essentially took nothing but C and assembler source code from various Dynamic C Premier libraries and pieced together the functionality of the RTL8019AS Ethernet IC. You used the Rabbit Semiconductor web site to view schematic drawings of the RCM2100 and technical updates relating to the hardware and software while reading this column. The open-source attitude that Z-World and Rabbit Semiconductor apply to their product lines makes products like the RCM2100 ideal learning tools.

Iım out of virtual paper. Next time Iıll show you some tricky hardware solutions based on the new Ethernet-based RabbitCore line.

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