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Hello everyone I am here once more ask for help to welcome the team matrixs .i am trying to implement USB with the PIC 18F14K50 ,but always appears message " Unknown Device(THE REQUEST FAILS TO RECEIVE DESCRIPTOR OF THE DEVICE) ".Can someone help me ???

I tried several settings and always the same problem unknown device .i did a simple program just for recognition of USB.Just to show i did the same program with PIC 18F2550 and it works.

Hello,

To make USB work correctly you need to be running the PIC at a specific clock speed (48MHz). The clock speed in your project options is set to 24MHz. So I suggest you change this to 48000000 and then using the 1 second flasher test go through your config settings and see if you can get the device running at the correct rate.

https://www.flowcode.co.uk/wikiv7/index. ... ED_flasher

Thank Benj for answer me one more time. I will make this test with an increase in the crystal.

After the tip of the master Benj, I was able to solve and understand what was happening for the non-operation of the Pic 18f14k50 with USB. I actually made my Hardware putting external crystal of 24mhz and with this will not work.Simply this pic 18f14k50 in case you want to use USB will only work with External crystal of 12mhz and you have to multiply PLL by 4 to make the 48Mhz needed to run or, So you can put an external Crystal of 48mhz direct. I thank Professor Benj for the help once more.
Genilson de Souza

Glad it fixed the problem for you and thanks for letting us know.

Also wish I was a professor maybe one day

Hi I am sorry to resurrect this topic.But now I need to use it with external 48mhz crystal without needing to use the PLL (x 4) has already made several attempts .But i am not able to make USB works with crystal of 48mhz .Windows does not recognize .

Seeing the datasheet of the pic 18f14k50 can be used in Crystal of 6mhz,12mhz or 48mhz to USB mode.Is it actually permitted use CRYSTAL 48Mhz with NODIV?

Returning to the topic to pass on information that I took on another site.To work with crystal of 48Mhz crystal JV has to be complete. As shown in table 2.4 of http:// http://ww1.microchip.com/downloads/en/D ... 41350C.pdf datasheet . CRYSTAL EC

Hello,

Have you now got this working?

A 48MHz crystal might kick out some high frequency EMF noise so be careful if its going into a product you need to certify for EMC.

Hello Benj i did test with crystal of 48MhZ model HS trying to use modulo USB and not worked ,but seeing the datasheet vi that can work with crystal of 48mhz but has to be the model EC of 4 pins.There in the datasheet is so
CRYSTAL 6Mhz EC/HS
CRYSTAL 12Mhz EC/HS
CRYSTAL 48Mhz EC
Passing on this information to all of the forum
Thank you