USBSERVICE And SERIN2 Odd Behavior

[rsocor01]

Hi,

I have the following code below where every once in a while I'm checking the incoming data using SERIN2. If I change the WAIT-TIME in SERIN2 from 5mS to 4mS or less the USB connection would get lost and disconnected intermittently. When I use a 5mS for WAIT-TIME the program is very stable. The length of the SERIN2 incoming package is 3.6mS. Any idea why is this happening? Should I increase that 5mS to 7 or 8mS? I believe that the USBSERVICE should be done every 10 milli seconds or less, is this correct? Is there a better way to do what I'm trying to accomplish?

Thanks,

Robert



FOR J = 0 TO 7
USBSERVICE
GOSUB SearchForClockSignal
USBSERVICE
IF ClockSignalFound = 1 THEN EXIT 'EXITS THE LOOP IF A CLOCK SIGNAL WAS RECEIVED
NEXT J

SearchForClockSignal:

USBSERVICE
SERIN2 PORTB.7, 32, 5, CLOCKSEARCHFAILED, [STR RFID_IN\7]
USBSERVICE

ClockSignalFound = 1 'SETS FLAG TO STOP SEARCH

CLOCKSEARCHFAILED:

return

[richard]

I believe that the USBSERVICE should be done every 10 milli seconds or less, is this correct? Is there a better way to do what I'm trying to accomplish?

its not so much as to service it every 10ms or less but to respond to polls before the host times you out. i use the isr option for usb service


ASM
INT_LIST macro ; IntSource, Label, Type, ResetFlag?

INT_Handler USB_INT, _DoUSBSERVICE, ASM, yes

endm
INT_CREATE
INT_ENABLE USB_INT
ENDASM



DoUSBSERVICE:
USBSERVICE ; Run the SERVICE routines
@ INT_RETURN


main issue with that is that bitbanged comms like serin/out can't tolorate the interrupts
serial comms needs to be via the eusart

[rsocor01]

Thanks, Richard. Now, I'm using the Darrel's USB interrupt and it helps. It is not really crucial in my program if a package is lost using the SERIN2 or SEROUT2 commands. I changed my code like it's shown below and it's working fine so far.



'FOR J = 0 TO 7
USBSERVICE
GOSUB SearchForClockSignal
USBSERVICE
'IF ClockSignalFound = 1 THEN EXIT 'EXITS THE LOOP IF A CLOCK SIGNAL WAS RECEIVED
'NEXT J

SearchForClockSignal:

USBSERVICE
SERIN2 PORTB.7, 32, 50, CLOCKSEARCHFAILED, [STR RFID_IN\7]
USBSERVICE

'ClockSignalFound = 1 'SETS FLAG TO STOP SEARCH

CLOCKSEARCHFAILED:

return

[richard]

if you are using USBSERVICE in a interrupt routine then its unnecessary to make additional calls to it , its probably not re-entrant code either.
making calls to it both inside and outside the isr may have unexpected consequences

[rsocor01]

Thanks, I haven't clean up the code yet. That makes sense about the unexpected issues.

[rsocor01]

This program having SERIN2 working together with a USB connection keeps giving me headaches :eek:. The first code below works fine for many straight hours and days. However the second code gets hung up after half an hour or so. This SUB is called once every second more or less. Is there anything that I'm missing here? Why does the second code gets hung up after a while?

THIS CODE WORKS FINE:



SearchForClockSignal:

@ INT_DISABLE USB_INT
PIR2.5 = 0

SERIN2 PORTB.7, 32, 5, CLOCKSEARCHFAILED, [STR RFID_IN\7]

@ INT_ENABLE USB_INT

'.... SOME CODE HERE TO PROCESS THE DATA

CLOCKSEARCHFAILED:
@ INT_ENABLE USB_INT

RETURN



THIS CODE GETS HUNG UP AFTER A WHILE:



SearchForClockSignal:

@ INT_DISABLE USB_INT
PIR2.5 = 0

FOR J = 0 TO 5
SERIN2 PORTB.7, 32, 5, CONTINUESERIN2, [STR RFID_IN\7]
CONTINUESERIN2:
USBSERVICE
IF RFID_IN[0] = 252 THEN EXIT 'THE DATA PACKAGE WAS RECEIVED
NEXT J

@ INT_ENABLE USB_INT

'.... SOME CODE HERE TO PROCESS THE DATA

CLOCKSEARCHFAILED:

RETURN

[richard]

since only code snippets posted and
no hardware description pic/usb descriptor and
no explanation why eusart not employed and
no description of failure point or why "working" code not suitable

for a meaningful forum response more detail would not go astray.

i'm only a novice at usb stuff at best but there is just not enough data to go on for me.
in general i would not expect two such asynchronous time critical services to ever be reliable on a single core device
without some hardware support.


some thoughts
SearchForClockSignal:
@ INT_DISABLE USB_INT
PIR2.5 = 0 ? why here
FOR J = 0 TO 5
SERIN2 PORTB.7, 32, 5, CONTINUESERIN2, [STR RFID_IN\7] ? 5ms ? usb can be polled at intervals down to 1ms device dependent
// what is your actual poll frequency ? use wireshark to get a picture of whats happening
CONTINUESERIN2:
USBSERVICE
IF RFID_IN[0] = 252 THEN EXIT 'THE DATA PACKAGE WAS RECEIVED
NEXT J
// no attempt here to clear irq flag before re engaging isr could be an issue
@ INT_ENABLE USB_INT

'.... SOME CODE HERE TO PROCESS THE DATA

CLOCKSEARCHFAILED:
RETURN