Specifications

The hardware features of the Ethernut kit are as follow:
Atmel ATmega 103 processor running at 3.6864 Mhz
Realtek IEEE 802.3 compliant Ethernet controller (10Mbit)
RS-232 serial port
128 Kbyte of programmable flash ROM
32 Kbyte SRAM
22 input/output lines
Two 8-bit and one 16-bit timer
The RAM space provides 32Kbytes and it was decided that this amount was adequate.
The Ethernut documentation [9] suggests that most typical applications running TCP
use between 5Kbytes and 10Kbytes of RAM. This leaves between 22Kbytes and
27Kbyted, which is what the project requires.
An example of integrating this Atmel processor with these types of MP3 decoders is the
YAMPP project [19]. It is another open source project. It is a MP3 player that retrieves
its data from a hard disk interface with FAT32 installed. This is a freely available
recourse project from the web, which can use either the MAS chip or the VLSI chip.
This demonstrates that the Atmel processors are capable of delivering the data fast
enough to these decoders.
To determine whether the Ethernut can transfer data fast enough across the network to
play MP3s the network capabilities of the Ethernut were investigated. For a 192Kbbs
MP3 file Winamp puts data into its buffer at a rate of about 30Kbytes/s (from tests
mention in Chapter 3). However, a data transfer speed of up to 50Kbytes/s has been
assured by the designer, Harald Kipp. [20] This will be ample to assure that a buffer
underrun will not occur. The bandwidth from the Atmel to the decoder was
demonstrated in the YAMPP project. It also showed that Atmel was able to supply
enough bandwidth to the MP3 decoder and at the same time was fast enough to take
data from the hard drive interface.
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