Hello community,
I have a question about method of ZQ automatic pull-down calibration.
In ZQ automatic Pull-up calibration(section 44.11.2.1.1), it say that
"The MMDC drives zq_pu_pd_sel to "1"for indication of pull-up calibration"
From Figure 44-8 in Reference manual, It will connect between internal pull-up and external pull-down
register and calibrate a ZQPAD voltage to Vdd/2.
In ZQ automatic Pull-down calibration(44.11.2.1.2), it say that
"The MMDC drives zq_pu_pd_sel to "0" for indication of pull-down calibration"
In Figure 44-8, it seems that detach internal pull-up register and attach internal pull-down register
to external register.
It seems that both internal and external register are pull-down so ZQPAD keep GND level.
So we think that in pull-down zq calibration, internal pull-up and internal pull-down register
will attached to the comparator and detach external register.
Is it correct understanding?
Best regards,
Ishii.
Solved! Go to Solution.
Hello,
Generally You are right:
The internal pull-up resistor calibration is done using the 1% external resistor.
The internal pull-down resistor calibration is done versus the internal pull-up resistor.
Have a great day,
Yuri
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Note: If this post answers your question, please click the Correct Answer button. Thank you!
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Hello,
Generally You are right:
The internal pull-up resistor calibration is done using the 1% external resistor.
The internal pull-down resistor calibration is done versus the internal pull-up resistor.
Have a great day,
Yuri
-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------
Hello Yuri,
Thank you for your quick response.
I will answer it to my customer.
Best regards,
Ishii.