AOpen MX36LE-N, Руководство пользователя

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C C O O D D E E C C ( ( C C o o d d i i n n g g a a n n d d D D e e c c o o d d i i n n g g ) )
Normally, CODEC means a circuit that can do digital to analog conversion and also the analog to digital conversion. It is part of
AC97 sound/modem solution.
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DIMM socket has total 168-pin and supports 64-bit data. It can be single or double side, the golden finger signals on each side
of PCB are different, that is why it was called Dual In Line. Almost all DIMMs are made by
SDRAM , which operate at 3.3V. Note
that some old DIMMs are made by FPM/ EDO and only operate at 5V. Do not confuse them with SDRAM DIMM.
E E C C C C ( ( E E r r r r o o r r C C h h e e c c k k i i n n g g a a n n d d C C o o r r r r e e c c t t i i o o n n ) )
The ECC mode needs 8 ECC bits for 64-bit data. Each time memory is accessed; ECC bits are updated and checked by a
special algorithm. The ECC algorithm has the ability to detect double-bit error and automatically correct single-bit error while
parity mode can only detect single-bit error.
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The EDO DRAM technology is actually very similar to FPM (Fast Page Mode). Unlike traditional FPM that tri-states the memory
output data to start the pre-charge activity, EDO DRAM holds the memory data valid until the next memory access cycle, that is
similar to pipeline effect and reduces one clock state.
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