USB CDC Communications for Dummies!

[ricgar]

Hi Guys

I'm pretty new to all of this, but here's my attempt.

I've attached a schematic of the device i am using.

What i am attempting to make here is some sort of USB to Serial Port Converter.

The code i loaded onto the chip is as follows:

'****************************************************************
'*  Name    : UNTITLED.BAS                                      *
'*  Author  : [select VIEW...EDITOR OPTIONS]                    *
'*  Notice  : Copyright (c) 2009 [select VIEW...EDITOR OPTIONS] *
'*          : All Rights Reserved                               *
'*  Date    : 2009/01/02                                        *
'*  Version : 1.0                                               *
'*  Notes   :                                                   *
'*          :                                                   *
'****************************************************************
@   __CONFIG	_CONFIG1L, _PLLDIV_5_1L & _CPUDIV_OSC1_PLL2_1L & _USBDIV_2_1L
@	__CONFIG	_CONFIG1H, _FOSC_HSPLL_HS_1H & _FCMEN_OFF_1H & _IESO_OFF_1H
'_CONFIG1H, _FOSC_XTPLL_XT_1H 
@	__CONFIG	_CONFIG2L, _PWRT_ON_2L & _BOR_ON_2L  & _BORV_28_2L  & _VREGEN_ON_2L
@	__CONFIG	_CONFIG2H, _WDT_OFF_2H
@	__CONFIG	_CONFIG3H, _MCLRE_ON_3H & _LPT1OSC_OFF_3H & _PBADEN_OFF_3H & _CCP2MX_ON_3H
@	__CONFIG	_CONFIG4L, _STVREN_ON_4L & _LVP_OFF_4L & _XINST_OFF_4L & _DEBUG_OFF_4L

' ****************************** Configure Hardware *********************************************
trisb = %11111100
trisc = %10111111       	' Set TX (PortC.6) to out, rest in
spbrg = 25            		' Calculate ((CPU speed mhz/Baud)/16)- 1  25 = 115200 baud  EX:((48000000/115200)/16)-1
rcsta = %10010000       	' Enable serial port and continuous receive
txsta = %00100000       	' Enable transmit and asynchronous mode/brgh = 0 bit 2
baudcon =%00001000			' Bit3 = 1: High speed usart 16 bit  

'***************************** Variables ******************************************
USBBufferTX Var Byte[1]
USBBufferRX var Byte[1]
USBBufferCount Var Byte
SerBufferTX Var Byte
SerBufferRX var Byte[1]
BufferRX var Byte
SerBufferCount Var Byte
Indexer var byte
Xmit_Start var bit									' Start serial data transmission
Status_Bits var byte								' Status bits to Pc
Data_Delay var word									' Delay for dataout
Data_Out var word									' Data 

Status_Bits = 0

LED	Var	PORTB.1

Define  OSC     48

	USBInit
	high led
	pause 1000
	Low LED		' LED off
    USBService

    for Indexer = 0 to 0
	   USBBufferRX[Indexer]= 0
    next

    usbbuffercount = 1
    
    
main:
    goSUB usb_rx
    goSUB com_rx
goto main    

	' Transmit USB Data     
USB_TX:
					' TX buffer size
USBService 
USBOut 3, serBufferrX, USBBufferCount, main 			' Transmit data		
RETURN

	' Receive USB Data 
USB_RX: 
USBService 											
USBIn 3, USBBufferRX, USBBufferCount, exitsub 		' Receive data if available,then exit
serbuffertx=usbbufferrx[0]
goSUB com_tx
return
'GOSUB Main


'Serial Receive

COM_RX:
hserin 1, exitsub, [bufferrx]
serbufferrx[0]=bufferrx
goSUB usb_TX
goSUB main

'Serial Transmit
COM_TX:
hserout [serbuffertx]
RETURN

exitsub:
return

Now this code compiles and i can connect via a hyperterminal to both the USB virtual and the physical Serial port. However if i enter anything in either of hyperterminals, it gives nothing and after a while of constant typing the hyperterminals start freezing on me. So i take it i've done something horrifically wrong.

Any suggestions?