TI中文支持网Part Number:DS125DF1610
Hi，
The datasheet did not tell it is pulled-up or pull-down for TDO_IO in the IC of DS125DF1610.
We tested and find TDO_IO always in low voltage if ther is no JTAG signal.
Is it pulled-down in the IC? What's the value of pulled-down?
TMS,TCK,TDI are pulled-up in the IC,What's the value of pulled-up?
Kailyn Chen：
Hello， the JTAG inputs are internally pulled-up。
The datasheet didn't provide the pull up value so I need to confirm it.
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Kailyn Chen：
As to the TDO_IO, it didn't described it has been internal pull down, so I need to confirm again.
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Michael Geng：
Hi, Kailyn
Are they confirmed about pulled-up vaule of TDI and pulled-down value of TDO？
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Kailyn Chen：
Sorry, I haven't receive reply, once I received reply, I would forward to you as soon as possible.
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Kailyn Chen：
Hello, I have confirmed that the internal pull-up values on the JTAG input pins is 100kΩ.
As TDO_IO is an output driving the line, there is no strong internal pull-up or pull-down resistor included.
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Michael Geng：
Hi,Kailyn
We test the voltage of TDO, it always in low voltage. It seems TDO is pulled-down
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Kailyn Chen：
Hello, TDO_IO is JTAG Test Data Out, if there is no JTAG signal, it should have no output.
You said always low voltage, how much is the voltage?
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Michael Geng：
Hi, Kailyn
The TDO of retimer1 connect to TDI of retimer2 through a 0ohm resistor.
When we do boundry scan, the TDI voltage of retimer2 is about 2.6V; if there is no boundry scan, the TDI voltage of retimer2 is only 2.2V.
We remove this 0 ohm resistor and tested the TDO of retimer1, the low voltage is about 66mV.
The TDI voltage should be about 2.5V when there is no boundry scan, but it's only 2.2V, so we think there is something in TDO.
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Kailyn Chen：
Michael Geng said:We remove this 0 ohm resistor and tested the TDO of retimer1, the low voltage is about 66mV.
That means the retimer1 cut the TDO output to TDI input retimer 2?
Michael Geng said:The TDI voltage should be about 2.5V when there is no boundry scan, but it's only 2.2V, so we think there is something in TDO.
TDI input is floating of retimer2, and test it 2.2V? If yes, please change another IC to test again.
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Michael Geng：
Kailyn Chen said:That means the retimer1 cut the TDO output to TDI input retimer 2?
Yes, we want to test if it is caused by TDO of retimer2.
Kailyn Chen said:TDI input is floating of retimer2, and test it 2.2V? If yes, please change another IC to test again.
In this sutiation, The TDO of retimer1 connect to TDI of retimer2 through a 0ohm resistor.
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Kailyn Chen：
Hello，I need confirm this question again.
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Michael Geng：
Hi,Kailyn
How it's going on?
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Kailyn Chen：
I am so sorry, the confirmation results are replied tomorrow.
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Kailyn Chen：
Hello, sorry for your inconvenience that have caused to you.
About this question, I have escalated to E2E forum and our foreign engineer, and please check if I have described your problem correctly.
https://e2e.ti.com/support/interface-group/interface/f/interface-forum/1266748/ds125df1610-ds125df1610-jtag
