davyzhu
Advanced Member level 1
Hello all,
The first question, a set of LVDS signals were input via a parallel port and they will be translated to TTL voltage by a chip, I put 100 Ohm Parallel terminal resistors between the differencial signals, shall I put the 100 Ohm resistors near the parallel port or the voltage translating chip.
Another question, I make a download cable for xilinx chip, and there are two pair of connnectors from download cable to On-board JTAG,
(Like this: PC's Parallel Port --> Female Connector -->Long Line --> Another Female Connector --> On-board Male JTAG),
normally it maybe one connector between PC and board. My question is howto calculate the impedence and put how much Parallel terminal resistor on the board side (I found the download cable always cannot detect the chip).
Regards,
Davy Zhu
The first question, a set of LVDS signals were input via a parallel port and they will be translated to TTL voltage by a chip, I put 100 Ohm Parallel terminal resistors between the differencial signals, shall I put the 100 Ohm resistors near the parallel port or the voltage translating chip.
Another question, I make a download cable for xilinx chip, and there are two pair of connnectors from download cable to On-board JTAG,
(Like this: PC's Parallel Port --> Female Connector -->Long Line --> Another Female Connector --> On-board Male JTAG),
normally it maybe one connector between PC and board. My question is howto calculate the impedence and put how much Parallel terminal resistor on the board side (I found the download cable always cannot detect the chip).
Regards,
Davy Zhu
