USB CDC Communications for Dummies!

[sputnik77]

arniepj, I cannot get your code working either.

There are no config fuses set in the code, and I do not know what they are supposed to be for this application.

I cannot fing any hints in your code as to how to get it to work.

Any help is much appreciated.

[kirtcathey]

Thanks alot. I popped a 4MHz clock (in place of 12 MHz) and compiled successfully. However, with the same result: the program compiles and the chip is programmed fine. I plug the USB cable into the test PC (and others) and windows will prompt as an unrecognized device. I go into the driver configuration and when I load the .inf file, windows again prompts that there is no hardware information available.

Have gone through the data sheet and fuses very close ... but the same result, which has me wondering about the cdc drivers that I am using for the PC....

[Darrel Taylor]

If it compiles ... The number one cause of USB failure, is improper Oscillator Configurations.

For 4Mhz Crystal ...

@   __CONFIG   _CONFIG1L, _PLLDIV_1_1L & _CPUDIV_OSC1_PLL2_1L & _USBDIV_2_1L
@   __CONFIG   _CONFIG1H, _FOSC_HSPLL_HS_1H

For 8Mhz Crystal ...

@   __CONFIG   _CONFIG1L, _PLLDIV_2_1L & _CPUDIV_OSC1_PLL2_1L & _USBDIV_2_1L
@   __CONFIG   _CONFIG1H, _FOSC_HSPLL_HS_1H

For 20Mhz Crystal ...

@   __CONFIG   _CONFIG1L, _PLLDIV_5_1L & _CPUDIV_OSC1_PLL2_1L & _USBDIV_2_1L
@   __CONFIG   _CONFIG1H, _FOSC_HSPLL_HS_1H

For any of the above configurations, use ...

DEFINE OSC 48

Number two reason ... improper capacitance on VUSB pin. (0.22uF or higher)

#3, connecting +5V from USB port to +5V supply from powered project. (very bad)
Ok, that's not really #3, but it is bad.

[ScaleRobotics]

Here is some PBP 2.60 code (cut and pasted) from Darrel, with the "Hello World" example added in. Darrel's main code is taken from another thread, located here: http://www.picbasic.co.uk/forum/show...4292#post94292 . It uses DT_INTS ( instant interrupts ) to service the USB. As always, DT_INTS can then also be used for all types of other things, while the USB connection is kept alive.

'  Compilation of this program requires that specific support files be
'  available in the source directory.  For detailed information, see
'  the file PBP\USB18\USB.TXT.

'  Config files for PIC18F4550 with 20 mhz crystal

asm
        __CONFIG    _CONFIG1L, _PLLDIV_5_1L & _CPUDIV_OSC1_PLL2_1L & _USBDIV_2_1L
        __CONFIG    _CONFIG1H, _FOSC_HSPLL_HS_1H & _FCMEN_OFF_1H & _IESO_OFF_1H
        __CONFIG    _CONFIG2L, _PWRT_OFF_2L & _BOR_ON_2L & _BORV_3_2L & _VREGEN_ON_2L
        __CONFIG    _CONFIG2H, _WDT_ON_2H & _WDTPS_512_2H
        __CONFIG    _CONFIG3H, _CCP2MX_ON_3H & _PBADEN_OFF_3H & _LPT1OSC_OFF_3H & _MCLRE_ON_3H
        __CONFIG    _CONFIG4L, _STVREN_ON_4L & _LVP_OFF_4L & _ICPRT_OFF_4L & _XINST_OFF_4L
endasm
DEFINE OSC 48

INCLUDE "cdc_desc.bas" 'Descriptor file    for CDC    serial demo

;--- Setup Interrupts ------------------------------------------------------
INCLUDE "DT_INTS-18.bas"     ; Base Interrupt System
INCLUDE "ReEnterPBP-18.bas"  ; Include if using PBP interrupts
buffer    Var    Byte[16]
cnt    Var    Byte
ASM
INT_LIST  macro     ; IntSource,          Label,  Type, ResetFlag?
        INT_Handler     USB_INT,  _DoUSBSERVICE,   ASM,  yes
        INT_Handler     INT_INT,    _Handle_INT,   PBP,  yes
    endm
    INT_CREATE             ; Creates the Low Priority interrupt processor

    ;INT_ENABLE  USB_INT   ;we will do this after we initialize USB
    INT_ENABLE  INT_INT
ENDASM


;----[Initialise USB and Interrupts]----------------------------------------
    PAUSE 100                    ; Allow VUSB to stabilize
    USBINIT                      ; initialize the USB driver
    USBSERVICE                   ; service it once
    UIE = $7F                    ; enable USB interrupts
    UEIE = $9F                   ; enable USB Error interrupts
@   INT_ENABLE  USB_INT

;----[Main program loop]----------------------------------------------------
Main:
    cnt = 16        ' Specify input buffer size
    USBIn 3, buffer, cnt, main

' Message received
    buffer[0] = "H"
    buffer[1] = "e"
    buffer[2] = "l"
    buffer[3] = "l"
    buffer[4] = "o"
    buffer[5] = " "
    buffer[6] = "W"
    buffer[7] = "o"
    buffer[8] = "r"
    buffer[9] = "l"
    buffer[10] = "d"
    buffer[11] = 13
    buffer[12] = 10
    buffer[13] = 0

outloop:
    USBOut 3, buffer, 14, outloop

GOTO Main

;----[Interrupt handler -- Service USB]-------------------------------------
DoUSBSERVICE:
      USBSERVICE                   ; Run the SERVICE routines
@ INT_RETURN

;----[Interrupt handler -- INT]
Handle_INT:
 ; something here
@ INT_RETURN

[LinkMTech]

Using PBP 2.60A and MPASM for my 1st attempt with USB on a PIC18F2455, I followed these directions:

Copy the PBP\USB18 folder to a new location.
You do not want any files left over from previous versions of PBP, so don't try to copy it into an existing project folder.
Open and compile cdc_demo.bas with the proper chip selected.
Program the chip and test. Done deal.

Copied complete USB18 folder to Documents\MCS to work with.

Wouldn't even start to compile
1st error: Variable USBReserveMemory position request 1024 beyond RAM_END 1023
Did: Opened up PIC18F2455.BAS and enabled BANK4

Started compiling! only to end in errors...
2nd error: ERROR 180.....mcs\usb18\usb18mem.asm 116: RES directive cannot reserve odd number of bytes in PIC18 absolute mode
ERROR 231....usb18mem.asm 116: no memory has been reserved by this instruction
This was repeated for many lines.
Did: Looked at usb18mem.asm line 116 and 117 and on and could only stare.

; (See usbctrltrf.c)
ctrl_trf_state	res	1		; Control Transfer State
ctrl_trf_session_owner res 1		; Current transfer session owner 
wCount		res	2		; Data counter

Now what?
Reading through the forum for this problem and it seems I'm the only one? Can't be that special. Can someone please help a dude out?

[mackrackit]

The USB files need to be in the same directory as your project and it works best if each project has a directory of its own.

Does this example help any?
http://www.picbasic.co.uk/forum/cont...USB-SD-LOGGING

[ScaleRobotics]

Wouldn't even start to compile
1st error: Variable USBReserveMemory position request 1024 beyond RAM_END 1023
Did: Opened up PIC18F2455.BAS and enabled BANK4

Are you sure you are working with 2.60 files?

The BAS file should look like this to start with (no modifications required):

'****************************************************************
'*  18F2455.BAS                                                 *
'*                                                              *
'*  By        : Leonard Zerman, Jeff Schmoyer                   *
'*  Notice    : Copyright (c) 2008 microEngineering Labs, Inc.  *
'*              All Rights Reserved                             *
'*  Date      : 09/12/08                                        *
'*  Version   : 2.60                                            *
'*  Notes     :                                                 *
'****************************************************************

BANKA   $0000, $005F
BANK0   $0060, $00FF
BANK1   $0100, $01FF
BANK2   $0200, $02FF
BANK3   $0300, $03FF
BANK4   $0400, $04FF
BANK5   $0500, $05FF
BANK6   $0600, $06FF
BANK7   $0700, $07FF
'EEPROM  $F00000, $F000FF
LIBRARY "PBPPIC18"

        include "PIC18EXT.BAS"

PORTL   VAR     PORTB
PORTH   VAR     PORTC
TRISL   VAR     TRISB
TRISH   VAR     TRISC

        include "PBPPIC18.RAM"
USBMEMORYADDRESS Con    $400    ' USB RAM starts here

'*-----------------------* EOF 18F2455.BAS *--------------------*

[LinkMTech]

Thanks Dave, I'm gonna study the project for more insight.

Are you sure you are working with 2.60 files?

Just checked the files I have and nope! It's version 2.46!
When I upgraded to 2.60 recently I also downloaded the patch that included the missing PIC18's. Where did I miss getting the latest 2.60 files?

Okay just did some more digging and found the latest 18F2455.bas in the PBP folder not in the USB18 folder. Will keep looking for the rest.

[kirtcathey]

This might sound like a crazy question but....

Do I have to install a bootloader of some kind on the 18F2550? If so, where do I get hold of one compatible with the project(s) this thread is about?

This is a great thread. When I get it all going, will package and contribute accordingly.

--Kirt

[kirtcathey]

Thank you Darrel. Here are the configs from the code arnie posted earlier, which is very similar to the configs (except I used a 12 MHz oscillator) that I created earlier according to the data sheet and include file review.

asm
CONFIG_REQ
CONFIG1L = _PLLDIV_1_1L & _CPUDIV_OSC1_PLL2_1L & _USBDIV_2_1L
; ; ; USB clock source comes from the 96 MHz PLL divided by 2
; ; [OSC1/OSC2 Src: /1][96 MHz PLL Src: /2] Determines cpu speed
; No prescale (4 MHz oscillator input drives PLL directly)
CONFIG1H = _FOSC_XTPLL_XT_1H & _FCMEN_OFF_1H & _IESO_OFF_1H
; ; ; Oscillator Switchover mode disabled
; ; Fail-Safe Clock Monitor disabled
; XT oscillator, PLL enabled, XT used by USB
CONFIG2L = _PWRT_ON_2L & _BOR_ON_2L & _BORV_2_2L & _VREGEN_ON_2L
CONFIG2H = _WDT_OFF_2H
CONFIG3H = _MCLRE_ON_3H & _LPT1OSC_OFF_3H & _PBADEN_OFF_3H & _CCP2MX_ON_3H
CONFIG4L = _STVREN_ON_4L & _LVP_OFF_4L & _XINST_OFF_4L & _DEBUG_OFF_4L
; Removed ICPRT_OFF_4L used with 18F4550
endasm


Did not have the define statement included though.... try that and see soon.
Also, noticed that your oscillator settings were HS instead of XT.

--Kirt

[Darrel Taylor]

If you're trying to use the new style CONFIG with PBP, you should be aware that it can't be placed in your program.
It has to be the first thing loaded, which means it must be in a file that gets loaded before the PBP library. (Not fun)

The original __CONFIG statements are still the way to set configs with PBP.
In other words, please delete what you just posted from your program, and follow the suggested __CONFIG style.

Also, noticed that your oscillator settings were HS instead of XT.

HS mode will always drive a crystal that might qualify for XT mode. The reverse is not always true. I err on the Cautious side.

[kirtcathey]

Thank you Darrel.

I was going through that the other day and the only way I could get code to compile is the way it is written now... but apparently not compiling correctly.

When I use the __config statements, the following appears rather consistently.

AUTO2550.ASM 72 : Overwriting previous address contents (0000)
Error[118] C:\PROJECTS\KEYFER\AUTO2550\AUTO2550.ASM 72 : Overwriting previous address contents (0001)

This doesn't require a CDC bootloader for the PIC, does it? Also noticed that the cdc windows drivers only have an .inf file and a .cat file, but no .sys file.

--Kirt

[Darrel Taylor]

There we go. That one must be #3

What to do if i get "overwriting previous address content" error message? (mister_e)
http://www.picbasic.co.uk/forum/show...75&postcount=5