Pic 18f Usb

[Tissy]

Bruce, thanks ever so much for taking the time to reply and for starting me in the right direction. Indeed i now have VB talking to the PIC over USB.

Do you have any knowledge of the EasyHID application? Having used EasyHID to set the base code etc, when i look at the device manager, it only shows up as a 'USB Human Interface Device' and 'HID-Compliant Device' and not as i set in the EasyHID maker, such as 'USB LED Controller'.

I was expecting an .inf file or similar to be compiled. Is this something that needs to be done manually? It would be a nice touch to have that when i plug in the device, in the task bar, the name of this device is displayed like any other USB device when connected.

Thanks again for you kind help,

Steve Tisseyre

[Bruce]

Hi Steve,

The information you enter when creating USB framework files with EasyHID is just for the embedded side with a very handy .dll that handles host to function communications.

EasyHID just gives you the USB framework. As far as I know, it does not create a Windows .inf file. That's up to you to create.

If you don't have your own .inf file or HID driver, then Windows will install its own HID drivers, and your new USB gadget is just going to show up with the default Windows name in Device Manager like 'USB Human Interface Device' and 'HID-Compliant Device'.

If you're running XP, look in the Windows input.inf file, and you'll see why. It tries to match the descriptors, VID, PID with existing "certified" manufacturers & hardware. If your new USB gadget isn't in the list, Windows uses the default HID compliant description with generic HID drivers.

Download the Microchip USB framework and take a look at how they setup the .inf & driver files. That will help you understand what's required.

If you plan on making a USB enabled "product", then you might also want to grab a copy of Jan Axelson's USB Complete 3rd edition. It's worth every penny, and gives you details on how to get your USB product/manufacturer name to show up in Windows Device Manager.

EasyHID will get you started, (and really quick I might add), but there's still a lot left to the end user to figure out.

Hats off to Dave at Mecanique for putting in the HUGE amount of time & study required just to give everyone that nifty "free" utility.

[Tissy]

Hi Bruce,

I have now ordered the book as you recommended, i'm sure it will come in very handy.

I have figured out that if you use EasyHID to set the maximum Buffer size to 32, then you can increase the amount of outputs on the PIC that you can set HIGH or LOW. ie the PIC side is odd numbers 1 - 31 and the VB side is even numbers 2 - 32.

ie on the PIC side requires:

PORTC.1 = USBBuffer[23]

where as on the VB side requires:

BufferOut(24) = 1 ' LED on

If i want to use all of PORTA and PORTB, is there an easy way of listing these in the two codes, or do they have to be done seperately? ie:

PIC
PORTA.1 = USBBuffer[1]
PORTA.2 = USBBuffer[3]
PORTA.3 = USBBuffer[5]
PORTA.4 = USBBuffer[7]
PORTA.5 = USBBuffer[9]

VB
BufferOut(2) = 1 ' LED on
BufferOut(4) = 1 ' LED on
BufferOut(6) = 1 ' LED on
BufferOut(8) = 1 ' LED on
BufferOut(10) = 1 ' LED on

Moving on from the switching of outputs HIGH or LOW, how would one send say text from the PIC to a text box in VB. For example, on the PIC, if a certain routine is executed, it sends a command to the VB application which is then displayed in a text window. Or is this getting too advanced for a quick explanation??

Thanks again for you assistance,

Steve

[andresnavas]

Hello. I don't know what happend but my EasyHID only create 4 files:
DESCUSBProject.asm
USBDESC.asm
USBProject.asm
USBProject.pbp

What i doing wrong? why it don't creat the other files like the USB18.c

Thanks for yours help!!!

Please if somebody have any example send it to me at: [email protected]

Thanks!

[Tissy]

andresnavas,

I have sent the reply straight to your personal email address. It would appear that the files aren't generating properly. All i can suggest is check the compilation settings again. If that doesn't work, try installing the application again.

I certainly haven't had any problems like that.

Within the directory you specified in the project settings (default is C:\Program Files\Mecanique\EasyHID\) should see another directory as per your title, such as USBProject. Within that directory is 2 sub directories, one for the VB or C code and one for the Proton or PICBasic code.

I have sent you a zip file containing what you should expect to see for a default VB and PICBasic code using the PIC18F4550 also with all the default settings.

Hope this helps,

Steve

[judy]

Hi all,

Absolutely brilliant thread, a lot of quality info and best of all can be done fast, cheers to all those involved. I am really new to this interfacing stuff, so if I'm asking too much or the newbie stink is unbearable, feel free to tell me to sling my hook.

I was wondering how one would go about changing the HID code provided by Easy HID USB code generator to simply read in up to three pulse width inputs (as far as I know the digital ins on the 18f2455 support this) and up to three analog ins through on board adc (ideally varying between -3 to +3v) simultaneously and as fast as possible, in fact how many samples per second is possible using the HID approach? Sin e.

I would greatly appreciate any help with this/direction to where help should be sought.

Thanks in advanced
Judy

[Bruce]

Steve,

You're dealing with bytes. PORTA.1 = USBBuffer[1] isn't the way to go since you can't place a byte value on a single port "bit".

Just place the byte you need on the whole port. You can send a single byte value from the PC app, and simply place it on the port.

I.E. PORTA = USBBuffer[1] should work fine - assuming that's the byte element you want.

Sending data from the PIC to PC is equally simple. Here's one example. Note this isn't everything. Just the sections I added to the framework file created with EasyHID.

DEFINE OSC 48
DEFINE LOADER_USED 1
DEFINE	ADC_BITS 10     ' Set number of bits in result
DEFINE	ADC_CLOCK 3     ' Set clock source /32
DEFINE	ADC_SAMPLEUS 50 ' Set sampling time in uS
DEFINE RESET_ORG 800h ' <-- I used the Microchip USB loader

BufferSize      con 8
DataBuffer      Var Byte(BufferSize) ' data buffer
DataBufferCount Var Byte             ' buffer size
Quanta  con 1251
TRISD = 0
PORTD = 0

' Variables
X       VAR byte
Adval   VAR WORD
   
    TRISA.0 = 1        ' RA0 input
    ADCON1 = %00001110 ' A/D channel 0
    ADCON2 = %10000011 ' Right justify for 10-bit
    USBInit

Main:
    GOSUB DoUSBIn
    PORTD = DataBuffer[7]
    
    ADCIN 0,adval		     ' Read A/D channel 0 into ADval variable
    ADval = ADval */ Quanta  ' Quanta result
    
    ' Load data buffer
    DataBuffer(0) = Adval DIG 3
    DataBuffer(1) = "."
    DataBuffer(2) = Adval DIG 2
    DataBuffer(3) = Adval DIG 1
    DataBuffer(4) = Adval DIG 0
    GOSUB DoUSBOut
    FOR X = 0 to 99 ' Short delay between updates
     PAUSEUS 1000
     USBSERVICE     ' Maintain HID connection during delay period
    NEXT X
    GOTO Main

On the PC side, modify the USB framework file created with EasyHID something like this;
Dim MyText As String ' create your string storage space

In the OnRead sub-routine;
MyText = (CStr(BufferIn(1)) + Chr$(BufferIn(2)) + CStr(BufferIn(3)) + CStr(BufferIn(4)) + CStr(BufferIn(5)) + "V")
Label1.Caption = MyText ' Place string text into label displaying A/D value

Judy,

Reading three pulse widths or A/D values doesn't really have anything to do with USB. The USB PIC is just another PIC with the addition of the USB module. Using the onboard A/D is pretty much the same as any other PIC.

All you need here is the datasheet, and a little time to experiment getting your pulse measurement & A/D routines working. Sending this all to the PC via the USB module is no more than stuffing your values into the outgoing buffer like in the previous example.

Just be sure to keep the USB connection alive by avoiding the use of blocking functions, long delays, etc,,. It's really not that hard, but you will need to experiment a tad.

[Demon]

...
Download the Microchip USB framework and take a look at how they setup the .inf & driver files. That will help you understand what's required.
...

Hi Bruce, do you have a link? I did a search on the Microchip site for <Microchip USB framework> and couldn't find a download.

(I'm assuming this is some sort of compile utility that will help Windows XP make a link between the USB device and our EasyHID-generated VB code.)

Robert

[Bruce]

Hi Robert,

The Microchip USB framework files are C18 code for the USB PIC. Look under Development Tools for PIC Demo Boards. Go to the page for the full speed USB board. All files & app notes can be downloaded from that page.

When you run the setup program for the PIC USB demo board it installs the framework files. You'll want to grab all the associated app notes on the same page, and USB loader if you plan on using that.

With PBP v2.46 you use DEFINE RESET_ORG 800h to force user code to start at the proper location when using the Microchip USB loader.

[Tissy]

Is the USB loader so you can bootload the PIC over USB with a new firmware?

[Bruce]

Yes. It's the same USB boot-loader provided with the Microchip full speed PIC USB demo board.

[Demon]

Is the USB loader so you can bootload the PIC over USB with a new firmware?

Yes. It's the same USB boot-loader provided with the Microchip full speed PIC USB demo board.

I wasn't planning on using In Circuit Serial Programming at first, but if we can include a user-friendly firmware upgrade feature then that changes everything.

Robert

[Tissy]

OK. I haven't got the USB Demo board, i just use the 18F2550 and 18F4550.

I will have to look at this, because the device i am designing is a USB device. So it would be good to be able to flash it for an upgrade using this facility over USB without worrying about other IcSP connections etc.

[LordLafebre]

Hi Everybody...

there is a schematic for Bruce's example...?

Sorry but my english is not good....!

Regards...!

GIO

[RYTECH]

Hi i've recently begun experimenting with the 18F4550 i've got a working example program that lets me flash an led connected to PORTB.7, I use VB6 on the PC side.

Basically my project has been halted by an unexpected problem in compiling some code added to work the A/D. Both Bruce's USB_AD.zip example and my own code cannot compile this:

ADCON1 = %00001110 ' A/D channel 0
ADCON2 = %10000011 ' Left justify for 10-bit

I get a syntax error.... any ideas - full code posted below.

I'm running version 2.2.1.1 of microcode studio. I'm using the new beta program for the EPIC parallel programmer (with the 40 pin adapter)



DEFINE OSC 20
DEFINE LOADER_USED 1
'ADC defines
Define ADC_BITS 10 ' Set number of bits in result
Define ADC_CLOCK 3 ' Set clock source /32
Define ADC_SAMPLEUS 50 ' Set sampling time in uS
Quanta con 1251
Adval VAR WORD

USBBufferSizeMax con 64 ' maximum buffer size
USBBufferSizeTX con 64 ' input
USBBufferSizeRX con 64 ' output

' the USB buffer...
USBBuffer Var Byte[USBBufferSizeMax]
USBBufferCount Var Byte
x VAR BYTE


TRISA.0 = 1 ' RA0 input

ADCON1 = %00001110 ' A/D channel 0
ADCON2 = %10000011 ' Left justify for 10-bit

usbinit ' initialise USB...
x = 0
LOW PORTB
BlinkLED:
if x = 7 then ProgramStart
x = x + 1
HIGH PORTB.7
PAUSE 1000
LOW PORTB.7
PAUSE 500
goto blinkLED
ProgramStart:
x = 0
gosub DoUSBIn
gosub DoUSBOut
goto ProgramStart

' ************************************************** **********
' * receive data from the USB bus *
' ************************************************** **********
DoUSBIn:
USBBufferCount = USBBufferSizeRX ' RX buffer size
USBService ' keep connection alive
USBIn 1, USBBuffer, USBBufferCount, DoUSBIn ' read data, if available
if usbbuffer[2] = 1 then
high portb.7
ENDIF
IF USBbuffer[2] = 0 THEN
LOW portb.7
ENDIF
goto DoAD
return
DoAD:
ADCIN 0,adval ' Read A/D channel 0 into ADval variable
ADval = ADval */ Quanta ' Quanta result

' Load data buffer
USBBuffer[0] = Adval dig 3 'Y.LowByte
USBBuffer[1] = "."
USBBuffer[2] = Adval DIG 2
USBBuffer[3] = Adval DIG 1
USBBuffer[4] = aDVAL DIG 0
RETURN
' ************************************************** **********
' * wait for USB interface to attach *
' ************************************************** **********
DoUSBOut:
USBBufferCount = USBBufferSizeTX ' TX buffer size
USBService ' keep connection alive
USBOut 1, USBBuffer, USBBufferCount, DoUSBOut ' if bus available, transmit data
return

[gigel]

I am trying to link my PC to my experimental board with PIC18F4550.
I am using EasyHID (mcHID.dll in delphi - for PC, and PROTON IDE for firmware from PIC) but the speed transfer of data from PC to PIC is very slow - about 64KB/sec.
I need more speed - I need over 240KB / sec. How can I make this data transfer to be fasterthan now?

Thank you