port i/o under winxp

[Opcode]

Take a look in the nohaven reply to this thread:
http://board.win32asmcommunity.net/viewtopic.php?p=153900#153900
Maybe the function NtSetInformationProcess is the answer to your question
to access I/O ports without a driver.

Regards,
Opcode

[Howard]

Hi
I played around with comms a lot in XP last year, and have pretty good success at 19.2K, using standard Windows drivers. Originally got the IO permissions map scheme to work OK, but then MS issued a security fix midway thru year, which wiped it. So had to do it the proper way. If you still want I can give details. There is support for watching the handshake lines etc.

Howard

[sbrown]

Hi
I played around with comms a lot in XP last year, and have pretty good success at 19.2K, using standard Windows drivers. Originally got the IO permissions map scheme to work OK, but then MS issued a security fix midway thru year, which wiped it. So had to do it the proper way. If you still want I can give details. There is support for watching the handshake lines etc.

Howard

Yes! Can you post it?


Scott

[Howard]

Hi Scott
As farrier has earlier mentioned, this method is based on Createfile,ReadFile & Writefile.

Refer MSDN - Excellent, though a little confusing, Technical Article entitled "Serial Communications in Win32"
and documentaion on CreateFile, SetUpComm, SetCommState, SetCommTimeouts, WriteFile & ReadFile.

I found the Timeouts (for retries) to be the critical area. It seems that because Windows is Pre-emptive Multi, it can
occasionally miss a received chtr or 2 in a good sized block (often up to 7 or 8 in a 6000h length block), and then will
of course just sit there waiting for the missed chtrs to turn up (since a fixed length RX). My selection works well for
my app. under Win98, XP Home, & XP Prof on a range of different speed machines.

Code Select Expand



;This code was built using Ramon's EasyCode

.Data?
EBuff DB 128 Dup(?)
.Data
ComPort DB 16 Dup(0)
hPS DD 0
cto COMMTIMEOUTS <>

sDCB DCB <>
;brBits BITRECORD <1, 0, 0, 1, DTR_CONTROL_ENABLE, 0, 1, 0, 0, 0, 0, \
; RTS_CONTROL_ENABLE, 0, 0>
brBits DD 1099H ;since structure above doesn't work

.Code

;I use a dialog box to select the comm port

dlgConfigureProcedure Proc Private hWnd:HWND, uMsg:ULONG, wParam:WPARAM, lParam:LPARAM
.If uMsg == WM_CREATE
Invoke GetWindowItem, hWnd, IDC_DLGCONFIGURE_PORTSELECT
Mov hPS, Eax
fn SendMessage, hPS, CB_ADDSTRING, 0, "COM1"
fn SendMessage, hPS, CB_ADDSTRING, 0, "COM2"
fn SendMessage, hPS, CB_ADDSTRING, 0, "COM3"
fn SendMessage, hPS, CB_ADDSTRING, 0, "COM4"



.ElseIf uMsg == WM_CLOSE
Invoke SendMessage, hPS, WM_GETTEXT, 16, Addr ComPort
.If Eax > 0
Invoke CreateFile, Addr ComPort, GENERIC_READ Or GENERIC_WRITE, \
0, NULL, OPEN_EXISTING, 0, NULL
.If Eax == INVALID_HANDLE_VALUE
Jmp OpenError
.EndIf
Mov hCom, Eax

Invoke SetupComm, hCom, 6010H, 6010H ;Setup Comms buffers - I TX/RX chunks 6000h long in my app.

Mov sDCB.DCBlength, SizeOf sDCB
Mov sDCB.BaudRate, CBR_19200
Mov Eax, brBits
Mov sDCB.fbits, Eax
Mov sDCB.ByteSize, 8
Mov sDCB.Parity, NOPARITY
Mov sDCB.StopBits, ONESTOPBIT

Invoke SetCommState, hCom, Addr sDCB
.If !Eax
Jmp DCBError
.EndIf

Mov cto.ReadIntervalTimeout, 10000
Mov cto.ReadTotalTimeoutMultiplier, 1
Mov cto.ReadTotalTimeoutConstant, 2000
Mov cto.WriteTotalTimeoutMultiplier, 10
Mov cto.WriteTotalTimeoutConstant, 10000
Invoke SetCommTimeouts, hCom, Addr cto
.If !Eax
Jmp DCBError
.EndIf

Jmp CloseOut
.Else
Jmp CloseOut
.EndIf
OpenError:
fn MessageBox, NULL, "Comms Port Not Available", "Open Comms Port",
MB_OK Or MB_ICONWARNING ;Normally means another app. has grabbed it.
Jmp CloseOut
DCBError:
        Invoke GetLastError
        mov     ecx,eax
        invoke  FormatMessage,FORMAT_MESSAGE_FROM_SYSTEM,NULL,ecx,0,ADDR EBuff,128,NULL
        fn MessageBox, NULL, Addr EBuff, "Open Comms Port", MB_OK Or MB_ICONWARNING


CloseOut:
Invoke IsModal, hWnd
.If Eax
Invoke EndModal, hWnd, IDCANCEL
Return TRUE
.EndIf
.Endif
Return FALSE
dlgConfigureProcedure EndP

;***********************
;SENDING MODULE snippets

;***********************
.Const
ACK Equ 06
NAK Equ 15H

.Data?

.Data
hCom DD 0 ;Port handle
HBuff DB 8 Dup(0)
BCount DD 0
Buffer DB 260 Dup(0)
hCount DD 0 ;Static Count Box in Fetch or Send
Buff5 DB 12 Dup(0)
FCommand DB 0F5H, 0FBH, 0F0H

.Code

SndCommand Proc lpCommand:DWord

;BOOL WriteFile(
;  HANDLE hFile,                    // handle to file
;  LPCVOID lpBuffer,                // data buffer
;  DWORD nNumberOfBytesToWrite,     // number of bytes to write
;  LPDWORD lpNumberOfBytesWritten,  // number of bytes written
;  LPOVERLAPPED lpOverlapped        // overlapped buffer (- I haven't tried Overlapped)

Invoke WriteFile, hCom, lpCommand, 3, Addr BCount, NULL
.If !Eax
Call Err1
Return FALSE
.ElseIf BCount != 3
Call Err2
Return FALSE
.EndIf

;My app. expects an immediate reflection of the command
Invoke ReadFile, hCom, Addr Buffer, 3, Addr BCount, NULL
.If !Eax
Call Err1
Return FALSE
.ElseIf BCount != 3
Call Err4
Return FALSE
.EndIf

Lea Esi, Buffer
Mov Edi, lpCommand
Mov Ecx, 3
Repe Cmpsb ;Ensure reflection correct
Jz ReflOK
Call SndNAK
Jmp SndCommand
ReflOK:
Call SndACK
Return Eax
SndCommand EndP



SndNAK:
Mov Al, NAK
Jmp SndSingle
SndACK:
Mov Al, ACK
SndSingle:
Mov [HBuff], Al
Invoke WriteFile, hCom, Addr HBuff, 1, Addr BCount, NULL ;snd C/S
.If !Eax
Jmp Err1
.EndIf
.If !BCount
Jmp Err2
.EndIf
Return TRUE


Err1:
    Invoke GetLastError
    Mov Ecx, Eax
    Invoke  FormatMessage, FORMAT_MESSAGE_FROM_SYSTEM, NULL, Ecx, 0, Addr Buffer, 128, NULL
Return FALSE

Err2:
fn MessageBox, NULL, "Send Timeout", "Comms Error", MB_OK Or MB_ICONWARNING
Return FALSE

Err4:
fn MessageBox, NULL, "Receive Timeout:", "Comms Error", MB_OK Or MB_ICONWARNING
Return FALSE



Howard

[sbrown]

Howard,

Thanks! I'll look through it later on. :U


Scott