USB CDC Communications for Dummies!

[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.

[LinkMTech]

Okay, just copied the 18F2455.bas ver. 2.60 from the PBP folder over to the USB18 folder to replace the ver. 2.46 and it compiled 100%!
Fingers are twitching, but need to wait until the coast is clear here before I can test it.

Thank you for the help.

[mackrackit]

You can have more than one version of PBP installed.
I have directories
C:\PBP_247
C:\PBP_250
C:\PBP_260

Then "point" to the version I want from MCS or FineLine or what ever I am using to invoke the compiler.

So you may want to try a fresh install...

[xkocik00]

Hi guys,
can you help me with program USB CDC Communicator on uC PIC18F47J53?
I never use USB, this is my first try.
I tried use the sample code from USB18 (CDC_demo). I tried rewrite the code but without success.
Thx.

[xkocik00]

Proglem solved:

Must use #congif for PIC.

' USB sample program for PIC18F47J53 CDC serial port emulation
' Requires PBP 2.60 or later

Include "cdc_desc.bas" ' Include the HID descriptors

Define OSC 48

#CONFIG
CONFIG WDTEN = OFF ;WDT disabled (enabled by SWDTEN bit)
CONFIG PLLDIV = 3 ;Divide by 3 (12 MHz oscillator input)
CONFIG STVREN = ON ;stack overflow/underflow reset enabled
CONFIG XINST = OFF ;Extended instruction set disabled
CONFIG CPUDIV = OSC1 ;No CPU system clock divide
CONFIG CP0 = OFF ;Program memory is not code-protected
CONFIG OSC = HSPLL ;HS oscillator, PLL enabled, HSPLL used by USB
CONFIG FCMEN = OFF ;Fail-Safe Clock Monitor disabled
CONFIG IESO = OFF ;Two-Speed Start-up disabled
CONFIG WDTPS = 32768 ;1:32768
CONFIG DSWDTOSC = INTOSCREF ;DSWDT uses INTOSC/INTRC as clock
CONFIG RTCOSC = T1OSCREF ;RTCC uses T1OSC/T1CKI as clock
CONFIG DSBOREN = OFF ;Zero-Power BOR disabled in Deep Sleep
CONFIG DSWDTEN = OFF ;Disabled
CONFIG DSWDTPS = 8192 ;1:8,192 (8.5 seconds)
CONFIG IOL1WAY = OFF ;IOLOCK bit can be set and cleared
CONFIG MSSP7B_EN = MSK7 ;7 Bit address masking
CONFIG WPFP = PAGE_1 ;Write Protect Program Flash Page 0
CONFIG WPEND = PAGE_0 ;Start protection at page 0
CONFIG WPCFG = OFF ;Write/Erase last page protect Disabled
CONFIG WPDIS = OFF ;WPFP[5:0], WPEND, and WPCFG bits ignored
#ENDCONFIG


buffer Var Byte[16]
cnt Var Byte


OSCTUNE.6 = 1 ' Enable PLL for 18F47J50 family
Pause 10

USBInit ' Get USB going

'************************************************* ***************
'* Set PORTA, PORTB, PORTC, PORTD PORTE to input/output *
'************************************************* ***************
TRISA = %00100010 ' Set PORTA to output
TRISB = %00001000 ' Set PORTB to output
TRISC = %00---000 ' Set PORTC to output

PortA = %00000000 ' Set PORTA to 0
PortB = %00000000 ' Set PORTB to 0
PortC = %00000000 ' Set PORTC to 0
PortD = %00000000 ' Set PORTD to 0
PortE = %00000000 ' Set PORTE to 0


'************************************************* ***************
'* SET LCD *
'************************************************* ***************
' Define LCD registers and bits
Define LCD_DREG PORTD
Define LCD_DBIT 4
Define LCD_RSREG PORTB
Define LCD_RSBIT 0
Define LCD_EREG PORTB
Define LCD_EBIT 1
DEFINE LCD_LINES 2
DEFINE LCD_COMMANDUS 1500
DEFINE LCD_DATAUS 50

Pause 1000 ' Wait for LCD to start up

'************************************************* ***************
'* LOOP *
'************************************************* ***************
' Wait for USB input
idleloop:
USBService ' Must service USB regularly
cnt = 16 ' Specify input buffer size
USBIn 3, buffer, cnt, idleloop

' Message received
buffer[0] = "O"
buffer[1] = "K"
buffer[2] = 13
buffer[3] = 10
buffer[4] = 0

outloop:
USBService ' Must service USB regularly
USBOut 3, buffer, 5, outloop

Goto idleloop ' Wait for next buffer