USB CDC with DT_INTS

[Darrel Taylor]

Tachyon,

USBSERVICE is a PBP statement, not an ASM statement. So it can't be in an ASM/ENDASM block.
It must be like this ...

'----[Interrupt handler -- Service USB]--------------------------------------------------
USBServiceISR:
        USBSERVICE
@   INT_RETURN

Then add an underscore in the INT_Handler statement.

'---[Interrupts List]---
ASM
INT_LIST  macro   ;Source,   Label,          Type,  ResetFlag?
    INT_Handler   USB_INT,  _USBServiceISR,  ASM,   yes
    endm
    INT_CREATE
ENDASM

You can only have 1 USBINIT in your program.
And there should never be a USBSERVICE after the interrupt has been enabled.
Interrupting a USBSERVICE to do a USBSERVICE can cause bad things to happen.

'---[Initialize Chip]--------------------------------------------------------------------
InitChip:
	PAUSE 100
	USBINIT
	USBSERVICE
	UIE = $7F
	UEIE = $9F
;	PAUSE 500
;	USBINIT
;	USBSERVICE
	@ INT_ENABLE USB_INT
;	USBSERVICE

The following program works perfectly here on a LAB-XUSB with an 18F4550.

'***************************************************************************************
'	Title:		USB CDC and DT_INTS Testing
'	CPU:		18F4458
'   Clock:		20 MHz External Clock
'
'****************************************************************************************

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    _CONFIG1H, _FOSC_ECPLLIO_EC_1H & _FCMEN_OFF_1H & _IESO_OFF_1H
	__CONFIG    _CONFIG2L, _PWRT_OFF_2L & _BOR_ON_2L & _BORV_2_2L & _VREGEN_ON_2L
	__CONFIG    _CONFIG2H, _WDT_OFF_2H & _WDTPS_512_2H
	__CONFIG    _CONFIG3H, _CCP2MX_ON_3H & _PBADEN_OFF_3H & _LPT1OSC_OFF_3H & _MCLRE_OFF_3H
	__CONFIG    _CONFIG4L, _STVREN_ON_4L & _LVP_OFF_4L & _XINST_OFF_4L & _DEBUG_OFF_4L
ENDASM


DEFINE OSC 48
DEFINE NO_CLRWDT 1
DEFINE USB_BUS_SENSE PORTD,3

INCLUDE "cdc_desc.bas"
INCLUDE "DT_INTS-18.bas"

'---[Interrupts List]---
ASM
INT_LIST  macro   ;Source,   Label,          Type,  ResetFlag?
    INT_Handler   USB_INT,  _USBServiceISR,  ASM,   yes
    endm
    INT_CREATE
ENDASM


	goto InitChip


'----[Interrupt handler -- Service USB]--------------------------------------------------
USBServiceISR:
	USBSERVICE
@	INT_RETURN



'---[Initialize Chip]--------------------------------------------------------------------
InitChip:
	PAUSE 100
	USBINIT
	USBSERVICE
	UIE = $7F
	UEIE = $9F
	@ INT_ENABLE USB_INT

	PORTA = 0
	PORTB = 0
	PORTC = 0
	PORTD = 0
	PORTE = 0

	'setup port i/o
	TRISA = %00000000
	TRISB = %11111111
	TRISC = %00110000
	TRISD = %00001000
	TRISE = %00000000

	'all dig
	ADCON1 = %00001111
	
	'enable port b pullups
	INTCON2.7 = 0

	

Main:
	goto Main


	end

Make sure you have 0.1uF bypass capacitors from VDD to VSS.
And some people say that you also need 0.1uF from the USB +5V to VSS, but I've never had to do that.

[MikeWinston]

Hello Darrel,
Sorry but that code is not connecting either. I copied everything over. And it compiles OK.
What is also concerning me is the version I have with the timer interrupt is also dropping the connection after about a half hour. This is after I shortened the interrupt time to 1.3ms. Should I shorten the time even more? Is it because its a USB 1.1 computer? I haven't seen
it drop the connection on a USB 2.0 computer yet.

I've tried all I could think of on the USB Interrupt version. I might have to give up on that one
for now and just focus on the timer interrupt version.

So I'll increase the size of cap on Vusb pin and see if that helps.

Do you think shortening the interrupt time will help?

Thank you for all your help.
Regards,
Mike

[MikeWinston]

Just an update if anyone is interested. The PIC on the USB 2.0 computer is over 6 hours and
has not dropped its connection. The same PIC on the USB 1.1 computer could not hold its
connection for longer than 20 minutes or so.
I am using a timer interrupt (0.6ms) to execute the USBSERVICE routine. If I ever find an
answer why than I will post it back here.

As far as the USB interrupt using DT-INTS-18 v34 for CDC, I haven't a clue why it won't
connect for me. I know the interrupt is not happening at all. And I know my hardware
works with the timer interrupt. If I find what I'm missing than I'll post that also.

Mike

[MikeWinston]

Eureka! Yes I'm that happy. I found the reason why the USB interrupt was not working.
It was the line I uncommented in the cdc_desc.bas file (#define USE_USB_BUS_SENSE_IO).

I read somewhere, don't remember where, when using self powered circuit one should
define a Vbus sense I/0 and uncomment the line above in the cdc_desc file. This is supposed to make the design more USB compliant. If the user unplugs the USB cable, the 3V reg. is turned off. I verified this with a meter and peeked how it is done in the assembly USBSERVICE routine.

I don't mind if the 3V reg. stays on in my design. I am using a power supply. But I guess
it might be a concern in a battery powered design.

I should have mentioned the uncommenting bit in my post. I ASSUMED....

Anyway, thanks Darrel for giving me my timer back.
This is fantastic -
Mike