USB to RS232 adapter

[PJALM]

Is it possible to use a PIC18F2550 as a USB to RS232 adapter with PBP by using the CDC mode?

[vacpress]

the microchip site has firmware to make a USB PIC into a serial convertor. It is fairly well documented. somewhere on the site

www.microchip.com

it is one of the first things i learned about when i began investigating PIC USB

-R

[Darrel Taylor]

Or, if you wanted to stick with PicBasic, you could try the usbcdc.bas example in the USB18 folder.

[PJALM]

I have looked at booth but they are incomplete.

I have tried to capture data from the RS232 port on the pic and output it to the USB and also from the USB to the RS232 with no sucess.

All examples are just on how to emulate the CDC.

I basically need a USB to RS232 adapter like those you can buy in any store.

I have tons of these 18F2550 chips and would rather use them to convert my exsisting projects instead of going and buying some.

[PJALM]

Ok, I got it to go from USB to the RS232 but I still cannot get the RS232 to USB to work. Here is the code I have so far.

DEFINE  OSC 48

INCLUDE "modedefs.bas"

Buffer   VAR BYTE[16]
Cnt      VAR BYTE
B0       VAR BYTE

PIC_TX   VAR PORTC.6     ' Transmit Pin
PIC_RX   VAR PORTC.7     ' Receive Pin

ADCON1 = 15              ' Set all I/Os to Digital
INTCON2.7 = 1            ' Disable PortB Pullups         
CMCON = 7                ' Disable Comparators

USBInit

' Main Program Loop
MainLoop:
    USBService           ' Must service USB regularly
    cnt = 16
    USBIn 3, Buffer, Cnt, MainLoop

    SEROUT2 PIC_TX,84,[STR Buffer\Cnt]
    
Get_RS232_Data:
    SERIN PIC_RX,T9600,100,Get_RS232_Data_Timeout,B0
    Buffer[0] = B0
    Cnt = 1
    GOTO OutLoop
    	
Get_RS232_Data_Timeout:
    Buffer[0] = 0
    Cnt = 0
    
OutLoop:
    USBService          ' Must service USB regularly
	
    IF Cnt > 0 Then
        USBOut 3, Buffer, Cnt, OutLoop
    ENDIF

    GOTO Mainloop

[skimask]

Using a MAX232 type chip in the circuit?
Depending, you might have to use N9600 instead of T9600