USBSERVICE + serout2 problem

[Darrel Taylor]

If you are trying to tie together USB_ASM_Service and the routine I gave in this thread, it won't work as is.

CDC uses a different endpoint than HID.

[aberco]

Well, I managed to make it all work... possibly partially but so far so good!

I can send and receive 32 bytes packets. However as you said I may have not modofied everything which makes TX_Ready and RX_Ready non functional. However they are tied to USB registers and should not be dependent to endpoints if my understanding of the datasheet was correct...



I'm pasting here part of the main code that I used:

INCLUDE "cdc_desc.bas"
INCLUDE "EEPROM_detect.pbp"

'*******************************************************
'Init the interrupt handling system
'*******************************************************
INCLUDE "DT_INTS-18.bas"     ; Base Interrupt System
INCLUDE "ReEnterPBP-18.bas"     ; Include if using PBP interrupts

ASM
INT_LIST  macro     ; IntSource,          Label,  Type, ResetFlag?
        INT_Handler     USB_INT,  _DoUSBSERVICE,   PBP,  yes
        INT_Handler     TMR1_INT,   _TempCheck,   PBP,  Yes
        INT_Handler     INT0_INT,   _USBAttached,   PBP,  Yes
    endm
    INT_CREATE ; Creates the Low Priority interrupt processor
ENDASM

INCLUDE "USB_ASM_Service.pbp"

[aberco]

Last edited by Darrel Taylor; - 10th October 2010 at 16:56. Reason: Incorrect Mod

Well ok, but what does makes it incorrect?

[aberco]

Ok, there's indeed something that relates to endpoint. I understand that you use two bytes located within the USB RAM space to get the TX and RX reports.

BD1STATOUT = _USBMEMORYADDRESS + 8 ; 408h or 208h
BD1STATIN = _USBMEMORYADDRESS + 0Ch ; 40Ch or 20Ch

Now I'm clueless about what this refers to... tried to look at the hid_desc.pbp/asm code and compare it with cdc_desc.pbp/asm, and also to look on the net for RAM endpoint allocation at these two address but no luck so far

[aberco]

Follow up on the monologue, and after a day of digging through literature, I now have a slightly deeper understanding of the USB protocol. The more helpful was Microchip datasheet, within the USB section related to BDT RAM.



200h is start of USB RAM for PIC18F1xK50, 400h for 18Fx550/x455/x450.

I moved the allocations to Endpoint 3 for CDC usage:

RXOWNED VAR BD3STATOUT.7 ; Out report Owned (OUT is PC to PIC)
TXOWNED VAR BD3STATIN.7 ; IN report Owned (IN is PIC to PC)
-------------------------------------------------------------------------------------------------------
BD3STATOUT = _USBMEMORYADDRESS + 18h ; 418h or 218h
BD3STATIN = _USBMEMORYADDRESS + 1Ch ; 41Ch or 21Ch

Bit 7 of BDxSTAT states which device (SIE or CPU) owns the right to write or read into the dual ported USB RAM space, so this is what is used for the TX and RX ready flag.

For some reason the compiler doesn't like the 3 in "BD3STATOUT and BD3STATIN" (Bad data type error). CONFIGURED_STATE should not differs between HID or CDC as it is not endpoint dependent.

[Darrel Taylor]

I moved the allocations to Endpoint 3 for CDC usage:
...
For some reason the compiler doesn't like the 3 in "BD3STATOUT and BD3STATIN"

You missed the EXT vars ...

BD3STATOUT         VAR BYTE EXT      ; OUT report status byte
BD3STATIN          VAR BYTE EXT      ; IN report status byte

[aberco]

Ah thanks! that was just above, an easy fix.

RX_Ready seems to work! but TX_Ready is always true... maybe because the time when the OUT endpoint is owned by the SIE is so short that I can't see it? However if I do a loop that sends data as soon as the SIE is ready I have huge data loss.
Right now I have to add a 200ms delay between each 32Bytes packets I send in order to avoid data transmission loss. It is rather slow... reading a 24LC512 at this speed would take a bit less than 4h.

Am I missing something here?