User manual

ECE 477 Final Report Spring 2004
The LCD screen will be the most expensive part of the design. Some of the larger
graphical displays can be up to $60 or $80, while some of the text only displays can be between
$20 and $40. Since one of the main focuses of our project is cost, we decided to send out many
requests for LCD displays and see what companies responded. In doing so, Microtips agreed to
supply us with their 128x128 Graphics Display for no cost. The Atmel microcontroller and
transceiver we have chosen also are each under $10. Therefore the total cost with all the other
minor parts will hopefully be under $35.
Rationale for Component Selection
Microcontroller:
We considered a few different microcontroller solutions, but we decided that the
ATmega88 [3-2] was the best to fit our needs. Atmel chips were originally chosen because they
offer a wide variety of chips with many I/O ports, on-chip peripherals, memory sizes, and low
power consumption. Along with this, the Atmel chips cost considerably less than Rabbit chips
[3-1] which have extra features and overhead that are not needed for our design. The PIC family
of microcontrollers is also worth a look. Although they are also low in cost, PIC
microcontrollers are designed to be high performance, and thus have a high clock frequency
which would not be as suitable for our needs since power consumption is a major factor in our
design.
Within the Atmel family, we decided to use the “Mega” series because of their extended
I/O pins and large amount of SRAM and EEPROM needed in the graphical menu display. The
memory size summary is shown below:
Device Flash EEPROM Interrupt Vector Size SRAM
ATmega48 4K Bytes 256 Bytes 1 instruction word/vector 512 Bytes
ATmega88 8K Bytes 512 Bytes 1 instruction word/vector 1K Bytes
ATmega168 16K Bytes 512 Bytes 2 instruction words/vector 1K Bytes
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