Ref Link : http://www.jtagtest.com/faq/jtag-ieee-1149-1/how-long-should-the-jtag-cable-be 這裡說的比較嚴格, 是 Follow JTAG IEEE 1149.1 Spec, Q: How long should the JTAG cable be?
Answer: Maximum cable length depends on communication speed and JTAG I/O voltage. For very low-speed JTAG communication the cable used can be as long as 50 cm (1.6 feet), for high speed JTAG try to keep connection as short as possible (i.e. 10cm / 0.3 feet).
Ref Link : http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.faqs/ka3595.html ARM 則是說 20 cm With the typical situation at the target end (weak drivers, no impedance matching resistors) you can only expect reliable operation over short cables (approx 20cm). If operation over this length is desired you will need to improve the circuitry used at the target end.
2 則留言:
不是兩米, 是 20 cm.(當時如果說成兩米, sorry!)
Ref Link : http://www.jtagtest.com/faq/jtag-ieee-1149-1/how-long-should-the-jtag-cable-be
這裡說的比較嚴格, 是 Follow JTAG IEEE 1149.1 Spec,
Q: How long should the JTAG cable be?
Answer:
Maximum cable length depends on communication speed and JTAG I/O voltage. For very low-speed JTAG communication the cable used can be as long as 50 cm (1.6 feet), for high speed JTAG try to keep connection as short as possible (i.e. 10cm / 0.3 feet).
Ref Link : http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.faqs/ka3595.html
ARM 則是說 20 cm
With the typical situation at the target end (weak drivers, no impedance matching resistors) you can only expect reliable operation over short cables (approx 20cm). If operation over this length is desired you will need to improve the circuitry used at the target end.
感謝Tony大大在多年以後回應我這篇文章
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