HARDWARE
I/O
pins were scarce, so I used the dedicated ADC
channels in the ATmega88’s TQFP package. I can
easily change to normal I/O pins if I need to
save some code size.
Figure
3 shows only the most important section of the
design. If you use an external crystal, you
don’t need to worry about the real-time clock,
which is used for a precision source to calibrate
the internal oscillator.
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(Click
here to enlarge)
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Figure
3—The LUB code runs from this schematic.
I’ve included only the FPGA’s programming
interface pins. The complete schematic
for my LoonBoard video development system
is posted on my web site (www.newae.com).
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