usb data logger using pic24fj64GB106........

[jit_singh_tara]

Dear Friends ,

Trying to interface usb mcu pic24fj64gb106 , There is no voltage on Vbus pin34 of the mcu ,When i connect the mcu to uart and hyper terminal it shows USB Error : overcurrent detected.

I am using AN1145 , Microchip application library usb thumbdrive data logger project.
Modified the usb_data_logger file .......

The circuit is :
View attachment ConverterRS-USB.pdf


Why there is no voltage on the Vbus pin ,and the error "**** USB Error : overcurrent detected.*****

What to do?

 

[Venkadesh_M]

I think the Vbus pin is 5V input pin If no voltage in that pin means the output is short circuited or overloaded..

 

[horace1]

overcurrent detected usually means you are attempting to pull too much current from a USB port
check for a short circuit on pin 1 of the USB connector

 

[jit_singh_tara]

I have connected my usb connector to the mcu ,

You mean to say that i am drawing too much current from the vbus pin of the mcu .......Can i connect the pen drive +pin( pin1) to 5V Directly........or what else can be done .

The problem is that even when the pen drive is not connected the over current error keeps on popping....on hyper terminal which is connected to the uart2 .

 

[Venkadesh_M]

Just give it 5V and check.

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Yeah You are absolutely missing that part

You have to give 5V to that pin in host mode

 

[horace1]

I have connected my usb connector to the mcu ,

You mean to say that i am drawing too much current from the vbus pin of the mcu .......Can i connect the pen drive +pin( pin1) to 5V Directly........or what else can be done .

The problem is that even when the pen drive is not connected the over current error keeps on popping....on hyper terminal which is connected to the uart2 .

missread your application!

your USB connector is wired so the PIC24 is a USB device, e.g. you connect it to a PC host and it appears as a mouse, HID device, etc depending what it is programmed as

your data logger application requires the PIC24 to act as a USB host and it should supply the 5volts to pin 1 of the connector, e.g. your circuit should be something like

 

[jit_singh_tara]

I tried that ,

now it is showing over current condition removed and after 2 sec again it is showing over current detected .... this is repeating again and again......

 

[Venkadesh_M]

to work proper you have to give 2.5V to analog pin and 5 v to Vbus.

 

[jit_singh_tara]

I havent given the divided signal to a/d pin ......is it also required if yes then at what pins.......

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I connected the 2.5 volt to the desired pin an8 now the error is gone....usb over current ....

But still i get a new error " No Media Present".

 

[Venkadesh_M]

did you give 5v to Vbus? and connect the flash drive. post your code.

 

[jit_singh_tara]

Please find the attached zipped file .

Running in c30 compiler , mplab x ide , pic24fj64gb106 .


"Not detecting the media ."

 

[horace1]

you have probably got the USB frequency incorrect
what is your crystal frequency?
check the config settings (I assume you did the modifications?)

    #elif defined(__PIC24FJ256GB106__)
    _CONFIG2(FNOSC_PRIPLL & POSCMOD_HS & PLL_96MHZ_ON & PLLDIV_DIV2) // Primary HS OSC with PLL, USBPLL /2
_CONFIG1(JTAGEN_OFF & FWDTEN_OFF & ICS_PGx2)   // JTAG off, watchdog timer off

        //_CONFIG1( JTAGEN_OFF & GCP_OFF & GWRP_OFF & COE_OFF & FWDTEN_OFF & ICS_PGx2) 
       // _CONFIG2( 0xF7FF & IESO_OFF & FCKSM_CSDCMD & OSCIOFNC_OFF & POSCMOD_HS & FNOSC_PRIPLL & PLLDIV_DIV3 & IOL1WAY_ON)

 

[jit_singh_tara]

Hi horace ,

I am using 20 Mhz Crystal ...and i havent selected the settings you indicated for the config bits.....

 

[Venkadesh_M]

What modifications you made in demo code?

 

[jit_singh_tara]

I got the modified code from the microchip support .......They changed the usb_data_logger.c file . I have posted the modified code project in earlier post .

 

[horace1]

I got the modified code from the microchip support .......They changed the usb_data_logger.c file . I have posted the modified code project in earlier post .

in hardwareprofile.h is

// Sample clock speed for a 16-bit processor
#if defined (__C30__) || defined __XC16__

    // Various clock values
    #define GetSystemClock()            32000000UL
    #define GetPeripheralClock()        (GetSystemClock())
    #define GetInstructionClock()       (GetSystemClock() / 2)

    // Clock values
    #define MILLISECONDS_PER_TICK       10
    #define TIMER_PRESCALER             TIMER_PRESCALER_8   // 8MHz: TIMER_PRESCALER_1
    #define TIMER_PERIOD                20000                // 10ms=20000, 1ms=2000

it looks like the code is built for an 8MHz crystal

either change the crystal or your config settings

 

[Venkadesh_M]

How did you got the MLA for C30 compiler, I am not able to do it by my self getting lot of errors..

 

[jit_singh_tara]

I tried 8 Mhz also ,

But same error : No Media Present .

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I am using c30 v 3.02 , i had been using it earlier in mplab 8......Now i am using it in mplabx ide .

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I am using the project from :

microchip_solutions_v 2013-06-15

 

[horace1]

I built
C:\microchip_solutions_v2013-06-15\USB\Host - Mass Storage - Simple Demo\Firmware\USB Host - MSD - Simple Demo - XC16.mcp

using the C30 compiler (I had to add heap and stack settings to the project)
and loaded it into a Bytronic Mechatronics trainer
**broken link removed**

which uses a PIC24FJ256GB110 with 8MHz crystal
plugged in a USB flash drive and the TEXT.TXT file was written OK

what is your circuit now?

 

[jit_singh_tara]

I tried to run the project as stated by you , but the device pic24fj64gb106 .


Project : Usb mass storage simple demo:

I added to turn on an led in the following code segment :

while(1)
{
//USB stack process function
USBTasks();

PORTCbits.RC14 = 0;

//if thumbdrive is plugged in
if(USBHostMSDSCSIMediaDetect())
{
PORTCbits.RC14 = 1; // if media detect turn on the led connected to rc14

deviceAttached = TRUE;

//now a device is attached
//See if the device is attached and in the right format
if(FSInit())
{
//Opening a file in mode "w" will create the file if it doesn't
// exist. If the file does exist it will delete the old file
// and create a new one that is blank.
myFile = FSfopen("test.txt","w");
.
.
.
.
.
.
.
.
.
.
.
}

By doing this i can say that the file test.txt is still not created , bcoz the led is never turned on which means it is not detecting the media ....now how do i check for this thing that why the usb is not getting detected in both the projects:


1. usb thumbdrive data logger .
2. Simple usb ms demo.

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Please check and tell if there is anything wrong with the schematic :