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Problem with VCCQ EMMC via ISP

Hi, the XGecu T56 has a problem with the VCCQ power supply when the programming through the ISP connector and the vccq power is taken from the zif panel pins.  If you put vcc3.3v \ vccq1.8v at the zif output of the panel vccq = 0.9-1.0v.  I have to submit vccq separately external power.  When I expose vcc3.3v \ vccq3.3v Everything is fine and vccq is 3.3v.  Why is voltage so low at 1.8?

That's what I do. Indicate it in the description. For a long time I figured out why there was no connection with emmc until I measured the power.

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回复 4# STALKER_71

Since there is only one VCC voltage inside the programming hardware, when VCCQ=VCC, VCCQ exists, but when VCCQ=1.8V and VCC=3.3V, VCCQ is high impedance. Generally when using ISP, use external the board's power supply instead of the optional power of the programmer.

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If i take VCCQ power from this pins voltage 0.9v
VCCQ.jpg

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Isp no vccq but zif panel have vccq and it low 0.9-1v.

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回复 1# STALKER_71
ISP no 1.8V VCCQ.

   http://forums.xgecu.com/viewthread.php?tid=71&;extra=page%3D1

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