[SOLVED] Problem to connect with USB self power to a PIC18F4550

Hi,

One of my studend has made a board to drive stepper motors.
The problem is that, the PC could not communicate with the PIC18F4550 in self power mode.
We use the PICDEM FS USB framework (HID custom demo modified software

The student has made a small board with an another PIC18F4550 in bus powered mode and it works.

We have verify the hardware, there no ground problem and the VUSB capacitor is on the board.

Could you please help us and give to us some ideas for investigate.

Thank you
Jose Miguel

Sir,
You have not specify the actual problem.
For example:-
1. Using USB connection, D7 Power LED is on or not?
2. Power LED is lit, but the system does not recognize the board.
3.The board is functioning, but has stopped communicating with the Demo Tool.
etc.
Normally, the PICDEM FS USB board behaves by default as a bus-powered device. If it is connected to a functioning USB portThere are some Common issues with the PICDEM FS USB demonstration board and it is discussed in chapter 6 of The PICDEM™ FS USB DEMONSTRATION BOARD USER’S GUIDE.
Also see
PC USB Host to a PIC HID Interfacing - Development by Example: Hardware and Protocol Stack.: **broken link removed**

joseMiguel said:

One of my studend has made a board to drive stepper motors.
The problem is that, the PC could not communicate with the PIC18F4550 in self power mode.
We use the PICDEM FS USB framework (HID custom demo modified software

The student has made a small board with an another PIC18F4550 in bus powered mode and it works.

Click to expand...

Can you post the schematic of the design? And code of the test application?

BigDog

hi all, i am the student of jose miguel who meet the problem to the device detection.

describe of the problem:

I work with the framework of microchip USB CUSTOM DEVICE, the USB POWER SENSE I/O is realize on RB4 on my board, the capacitor of 470nF on Vusb is good, we have controlled all the ground= no problem.

In HardwareProfile i have defined :

//The PICDEM FS USB Demo Board platform supports the USE_SELF_POWER_SENSE_IO
//and USE_USB_BUS_SENSE_IO features. Uncomment the below line(s) if
//it is desireable to use one or both of the features.


#define USE_SELF_POWER_SENSE_IO
#define tris_self_power TRISBbits.TRISB4 // Input
#if defined(USE_SELF_POWER_SENSE_IO)
#define self_power PORTBbits.RB4
#else
#define self_power 1
#endif

In the main.c, i have just remove the subroutines:

void BlinkUSBStatus(void);
BOOL Switch2IsPressed(void);
BOOL Switch3IsPressed(void);
WORD_VAL ReadPOT(void);

I don't have modified the usb_config and the usb_descriptor because i don't know wich modified parameters.

There are no problem for program the PIC with the ICD3, but USBdeviceSTATE is always =0x04 when the the program is stopped and =0x00 (detached state???) when the program run in debugger mode.

The host not detect the board also after a reset.


I can send to you my schematic and my code if you send me your email : bastien343085844@aol.com

Sorry for my english, no very good...


Thank you for your help

Hi all, you see here my schematics:




I don't succes to configure TRISB, who know where the bits are configured ?

Hi,

Thank you all.
We succeed to resolve the problem.
The PIC18F4550 had a bad behaviour(it had a destroyed USB or I/O port), but it was working with ICD3.
It's a pitty because the student has lost many hours.

Best regards
Jose Miguel

joseMiguel said:

We succeed to resolve the problem.
The PIC18F4550 had a bad behaviour(it had a destroyed USB or I/O port), but it was working with ICD3.
It's a pitty because the student has lost many hours.

Click to expand...

Yes, it is a pity, defective hardware can be difficult to troubleshoot.

I knew for from your previous posts, you are very familiar with the PIC18F4550, particularly the USB module. And from the russion's description the hardware appeared to be connected correctly.


Sorry, we could not be of more help in this case.

BigDog