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PIBASYN3.MOD
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1987-09-05
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(*----------------------------------------------------------------------*)
(* Async_Find_Delay --- Finds delay loop value for 1 millesecond delay *)
(*----------------------------------------------------------------------*)
PROCEDURE Async_Find_Delay( VAR One_MS_Delay : INTEGER );
(*----------------------------------------------------------------------*)
(* *)
(* Procedure: Async_Find_Delay *)
(* *)
(* Purpose: Finds loop count value to effect 1 ms delay *)
(* *)
(* Calling Sequence: *)
(* *)
(* Async_Find_Delay( VAR One_MS_Delay : INTEGER ); *)
(* *)
(* One_MS_Delay --- Resulting loop count for 1 ms delay *)
(* *)
(* Using result: *)
(* *)
(* Use loop of form: *)
(* *)
(* MOV CX,[>One_MS_Delay] *)
(* Delay: LOOP Delay *)
(* *)
(* to delay for 1 ms. *)
(* *)
(* Remarks: *)
(* *)
(* This routine watches over the CPU elapsed timer value for *)
(* just one timer interval (55 milleseconds). During that time *)
(* we run a tight loop and accumulate the ticks. The result *)
(* is the number of ticks required for a 55 ms delay. The *)
(* ticks for a 1 ms delay = ( ticks for 55 ms ) / 55. *)
(* *)
(* To avoid overflow problems on fast machines, and to ease the *)
(* worry about storing results at the second timer tick, we *)
(* break up the single long tight loop into a series of short *)
(* loops inside an outer loop. We check if the timer has *)
(* expired at the end of each inner short loop. Then the *)
(* time for the 55 ms delay is: *)
(* *)
(* Ticks_for_55 := Inner_Ticks * Outer_Ticks; *)
(* *)
(* and the corresponding 1 ms delay is: *)
(* *)
(* Ticks_For_1 := Ticks_For_55 DIV 55; *)
(* *)
(* To simplify things, we choose the inner tick value to be *)
(* 2 x 55 = 110. Then: *)
(* *)
(* Ticks_For_1 := ( 110 * Outer_Ticks ) / 55; ==> *)
(* Ticks_For_1 := 2 * Outer_Ticks; *)
(* *)
(* The CPU timer is located in four bytes at $0000:$46C. *)
(* Interrupt $1A also returns these bytes, but using the *)
(* interrupt results in an inaccurate loop count value. *)
(* *)
(* The local variables used here were moved to the data segment *)
(* since I couldn't get Turbo to generate the correct offsets *)
(* otherwise. *)
(* *)
(* Thanks to Brian Foley and Kim Kokonnen for help with this *)
(* problem. *)
(* *)
(*----------------------------------------------------------------------*)
(* STRUCTURED *) CONST
Hi_Timer : INTEGER = 0 (* Saves high portion of timer *);
Lo_Timer : INTEGER = 0 (* Saves low portion of timer *);
OutCount : INTEGER = 0 (* Accumulates outer loop counts *);
BEGIN (* Async_Find_Delay *)
INLINE(
$1E { PUSH DS ;Save DS}
{;}
/$8C/$C8 { MOV AX,CS}
/$8E/$D8 { MOV DS,AX ;Allow access to local variables}
{;}
/$31/$C0 { XOR AX,AX ;Clear AX to zero}
/$8E/$C0 { MOV ES,AX ;Allow low-memory access}
{;}
/$C7/$06/>OUTCOUNT/$00/$00{ MOV WORD [>OutCount],0 ;Clear outer loop counter}
{;}
/$FA { CLI ;No interrupts while reading}
/$26/$8B/$0E/>$46E { ES: MOV CX,[>$46E] ;Hi part of CPU timer value}
/$26/$8B/$16/>$46C { ES: MOV DX,[>$46C] ;Lo part of CPU timer value}
/$FB { STI ;Interrupts back on}
{;}
/$89/$0E/>HI_TIMER { MOV [>Hi_Timer],CX ;Save hi part of timer}
/$89/$16/>LO_TIMER { MOV [>Lo_Timer],DX ;Save low part of timer}
{;}
/$FA {Loop1: CLI ;No interrupts while reading}
{;}
/$26/$8B/$0E/>$46E { ES: MOV CX,[>$46E] ;Hi part of CPU timer value}
/$26/$8B/$16/>$46C { ES: MOV DX,[>$46C] ;Lo part of CPU timer value}
{;}
/$FB { STI ;Interrupts back on}
{;}
/$89/$C8 { MOV AX,CX ;Save CX and DX for later}
/$89/$D3 { MOV BX,DX}
{;}
/$2B/$06/>HI_TIMER { SUB AX,[>Hi_Timer] ;Subtract low order part}
/$1B/$1E/>LO_TIMER { SBB BX,[>Lo_Timer] ;Subtract high order part}
{;}
/$74/$E6 { JE Loop1 ;Continue until non-0 tick difference}
{;}
/$89/$0E/>HI_TIMER { MOV [>Hi_Timer],CX ;Save hi part}
/$89/$16/>LO_TIMER { MOV [>Lo_Timer],DX ;Save low part}
{;}
/$B9/$6E/$00 {Loop2: MOV CX,110 ;Run short delay loop.}
/$E2/$FE {Delay: LOOP Delay}
{;}
/$FA { CLI ;No interrupts while reading}
{;}
/$26/$8B/$0E/>$46E { ES: MOV CX,[>$46E] ;Hi part of CPU timer value}
/$26/$8B/$16/>$46C { ES: MOV DX,[>$46C] ;Lo part of CPU timer value}
{;}
/$FB { STI ;Interrupts back on}
{;}
/$FF/$06/>OUTCOUNT { INC WORD [>OutCount] ;Increment outer loop count}
{;}
/$2B/$0E/>HI_TIMER { SUB CX,[>Hi_Timer] ;Subtract low order part}
/$1B/$16/>LO_TIMER { SBB DX,[>Lo_Timer] ;Subtract high order part}
{;}
/$74/$E1 { JE Loop2 ;Keep going if next tick not found}
{;}
/$A1/>OUTCOUNT { MOV AX,[>OutCount] ;Pick up outer loop counter}
/$D1/$E0 { SHL AX,1 ;* 2 = ticks for 1 ms delay}
{;}
/$C4/$BE/>ONE_MS_DELAY { LES DI,[BP+>One_MS_Delay] ;Get address of result}
/$26/$89/$05 { ES: MOV [DI],AX ;Store result}
{;}
/$1F { POP DS ;Restore data segment register}
);
END (* Async_Find_Delay *);
(*----------------------------------------------------------------------*)
(* Async_Init --- Initialize Asynchronous Variables *)
(*----------------------------------------------------------------------*)
PROCEDURE Async_Init( Async_Buffer_Max : INTEGER;
Async_OBuffer_Max : INTEGER;
Async_High_Lev1 : INTEGER;
Async_High_Lev2 : INTEGER;
Async_Low_Lev : INTEGER );
(*----------------------------------------------------------------------*)
(* *)
(* Procedure: Async_Init *)
(* *)
(* Purpose: Initializes variables *)
(* *)
(* Calling Sequence: *)
(* *)
(* Async_Init( Async_Buffer_Max : INTEGER; *)
(* Async_OBuffer_Max : INTEGER; *)
(* Async_High_Lev1 : INTEGER; *)
(* Async_High_Lev2 : INTEGER; *)
(* Async_Low_Lev : INTEGER ); *)
(* *)
(* Calls: Async_Find_Delay *)
(* TurnOffTimeSharing *)
(* TurnOnTimeSharing *)
(* *)
(*----------------------------------------------------------------------*)
VAR
I: INTEGER;
(*----------------------------------------------------------------------*)
BEGIN (* Async_Init *)
(* Save data segment address in code *)
(* segment for use in serial port *)
(* interrupt handler. *)
Async_DSeg_Save := DSeg;
(* No port open yet. *)
Async_Open_Flag := FALSE;
(* No XON/XOFF handling yet. *)
Async_XOFF_Sent := FALSE;
Async_XOFF_Received := FALSE;
Async_XOFF_Rec_Display := FALSE;
Async_XON_Rec_Display := FALSE;
Async_Send_XOFF := FALSE;
Async_Send_Address := 0;
(* Set up empty receive buffer *)
Async_Buffer_Overflow := FALSE;
Async_Buffer_Used := 0;
Async_MaxBufferUsed := 0;
Async_Buffer_Head := 0;
Async_Buffer_Tail := 0;
(* Set up empty send buffer. *)
Async_OBuffer_Overflow := FALSE;
Async_OBuffer_Used := 0;
Async_MaxOBufferUsed := 0;
Async_OBuffer_Head := 0;
Async_OBuffer_Tail := 0;
(* Set default wait time for output *)
(* buffer to drain when it fills up. *)
Async_Output_Delay := 500;
(* No modem or line errors yet. *)
Async_Line_Status := 0;
Async_Modem_Status := 0;
Async_Line_Error_Flags := 0;
(* Get buffer sizes *)
IF ( Async_Buffer_Max > 0 ) THEN
Async_Buffer_Size := Async_Buffer_Max - 1
ELSE
Async_Buffer_Size := 4095;
IF ( Async_OBuffer_Max > 0 ) THEN
Async_OBuffer_Size := Async_OBuffer_Max - 1
ELSE
Async_OBuffer_Size := 1131;
(* Get receive buffer overflow *)
(* check-points. *)
IF ( Async_Low_Lev > 0 ) THEN
Async_Buffer_Low := Async_Low_Lev
ELSE
Async_Buffer_Low := Async_Buffer_Size DIV 4;
IF ( Async_High_Lev1 > 0 ) THEN
Async_Buffer_High := Async_High_Lev1
ELSE
Async_Buffer_High := ( Async_Buffer_Size DIV 4 ) * 3;
IF ( Async_High_Lev2 > 0 ) THEN
Async_Buffer_High_2 := Async_High_Lev2
ELSE
Async_Buffer_High_2 := ( Async_Buffer_Size DIV 10 ) * 9;
(* Allocate buffers *)
GETMEM( Async_Buffer_Ptr , Async_Buffer_Size + 1 );
GETMEM( Async_OBuffer_Ptr , Async_OBuffer_Size + 1 );
(* No UART addresses defined yet *)
Async_Uart_IER := 0;
Async_Uart_IIR := 0;
Async_Uart_MSR := 0;
Async_Uart_LSR := 0;
(* Set default port addresses *)
(* and default IRQ lines *)
FOR I := 1 TO MaxComPorts DO
BEGIN
Com_Base[I] := Default_Com_Base [I];
Com_Irq [I] := Default_Com_Irq [I];
Com_RS232[I] := Default_Com_RS232[I];
END;
(* Get the delay loop value for 1 ms *)
(* delay loops. *)
IF TimeSharingActive THEN
TurnOffTimeSharing;
Async_Find_Delay( Async_OneMSDelay );
IF TimeSharingActive THEN
TurnOnTimeSharing;
END (* Async_Init *);
(*----------------------------------------------------------------------*)
(* Async_Carrier_Detect --- Check for modem carrier detect *)
(*----------------------------------------------------------------------*)
FUNCTION Async_Carrier_Detect : BOOLEAN;
(*----------------------------------------------------------------------*)
(* *)
(* Function: Async_Carrier_Detect *)
(* *)
(* Purpose: Looks for modem carrier detect *)
(* *)
(* Calling Sequence: *)
(* *)
(* Flag := Async_Carrier_Detect : BOOLEAN; *)
(* *)
(* Flag is set TRUE if carrier detected, else FALSE. *)
(* *)
(* Calls: None *)
(* *)
(*----------------------------------------------------------------------*)
BEGIN (* Async_Carrier_Detect *)
Async_Carrier_Detect := ODD( Port[ UART_MSR + Async_Base ] SHR 7 ) OR
Async_Hard_Wired_On;
END (* Async_Carrier_Detect *);
(*----------------------------------------------------------------------*)
(* Async_Carrier_Drop --- Check for modem carrier drop/timeout *)
(*----------------------------------------------------------------------*)
FUNCTION Async_Carrier_Drop : BOOLEAN;
(*----------------------------------------------------------------------*)
(* *)
(* Function: Async_Carrier_Drop *)
(* *)
(* Purpose: Looks for modem carrier drop/timeout *)
(* *)
(* Calling Sequence: *)
(* *)
(* Flag := Async_Carrier_Drop : BOOLEAN; *)
(* *)
(* Flag is set TRUE if carrier dropped, else FALSE. *)
(* *)
(* Calls: None *)
(* *)
(*----------------------------------------------------------------------*)
BEGIN (* Async_Carrier_Drop *)
Async_Carrier_Drop := NOT ( ODD( Port[ UART_MSR + Async_Base ] SHR 7 ) OR
Async_Hard_Wired_On );
END (* Async_Carrier_Drop *);
(*----------------------------------------------------------------------*)
(* Async_Term_Ready --- Set terminal ready status *)
(*----------------------------------------------------------------------*)
PROCEDURE Async_Term_Ready( Ready_Status : BOOLEAN );
(*----------------------------------------------------------------------*)
(* *)
(* Procedure: Async_Term_Ready *)
(* *)
(* Purpose: Sets terminal ready status *)
(* *)
(* Calling Sequence: *)
(* *)
(* Async_Term_Ready( Ready_Status : BOOLEAN ); *)
(* *)
(* Ready_Status --- Set TRUE to set terminal ready on, *)
(* Set FALSE to set terminal ready off. *)
(* *)
(* Calls: None *)
(* *)
(*----------------------------------------------------------------------*)
VAR
Mcr_Value: BYTE;
BEGIN (* Async_Term_Ready *)
Mcr_Value := ( PORT[ UART_MCR + Async_Base ] AND $FE );
IF Ready_Status THEN
Mcr_Value := Mcr_Value OR 1;
PORT[ UART_MCR + Async_Base ] := Mcr_Value;
Async_Clear_Errors;
END (* Async_Term_Ready *);
(*----------------------------------------------------------------------*)
(* Async_Buffer_Check --- Check if character in buffer *)
(*----------------------------------------------------------------------*)
FUNCTION Async_Buffer_Check : BOOLEAN;
(*----------------------------------------------------------------------*)
(* *)
(* Function: Async_Buffer_Check *)
(* *)
(* Purpose: Check if character in buffer *)
(* *)
(* Calling Sequence: *)
(* *)
(* Flag := Async_Buffer_Check : BOOLEAN; *)
(* *)
(* Flag returned TRUE if character received in buffer, *)
(* Flag returned FALSE if no character received. *)
(* *)
(* Calls: None *)
(* *)
(* Remarks: *)
(* *)
(* This routine only checks if a character has been received *)
(* and thus can be read; it does NOT return the character. *)
(* Use Async_Receive to read the character. *)
(* *)
(*----------------------------------------------------------------------*)
BEGIN (* Async_Buffer_Check *)
Async_Buffer_Check := ( Async_Buffer_Head <> Async_Buffer_Tail );
END (* Async_Buffer_Check *);
(*----------------------------------------------------------------------*)
(* Async_Line_Error --- Check if line status error occurred *)
(*----------------------------------------------------------------------*)
FUNCTION Async_Line_Error( VAR Error_Flags: BYTE ) : BOOLEAN;
(*----------------------------------------------------------------------*)
(* *)
(* Function: Async_Line_Error *)
(* *)
(* Purpose: Check if line status error occurred *)
(* *)
(* Calling Sequence: *)
(* *)
(* Flag := Async_Line_Error(VAR Error_Flags: BYTE): BOOLEAN; *)
(* *)
(* Error_Flags --- Current error flags *)
(* *)
(* Flag returned TRUE if line status error occurred, *)
(* Flag returned FALSE if no error. *)
(* *)
(* Calls: None *)
(* *)
(* Remarks: *)
(* *)
(* The line status error flag is cleared here. *)
(* *)
(*----------------------------------------------------------------------*)
BEGIN (* Async_Line_Error *)
Async_Line_Error := ( Async_Line_Error_Flags <> 0 );
Error_Flags := Async_Line_Error_Flags;
Async_Line_Error_Flags := 0;
END (* Async_Line_Error *);
(*----------------------------------------------------------------------*)
(* Async_Ring_Detect --- Check for phone ringing *)
(*----------------------------------------------------------------------*)
FUNCTION Async_Ring_Detect : BOOLEAN;
(*----------------------------------------------------------------------*)
(* *)
(* Function: Async_Ring_Detect *)
(* *)
(* Purpose: Looks for phone ringing *)
(* *)
(* Calling Sequence: *)
(* *)
(* Flag := Async_Ring_Detect : BOOLEAN; *)
(* *)
(* Flag is set TRUE if ringing detected, else FALSE. *)
(* *)
(* Calls: None *)
(* *)
(*----------------------------------------------------------------------*)
BEGIN (* Async_Ring_Detect *)
Async_Ring_Detect := ODD( Port[ UART_MSR + Async_Base ] SHR 6 );
END (* Async_Ring_Detect *);
(*----------------------------------------------------------------------*)
(* Async_Send_Break --- Send break (attention) signal *)
(*----------------------------------------------------------------------*)
PROCEDURE Async_Send_Break;
(*----------------------------------------------------------------------*)
(* *)
(* Procedure: Async_Send_Break *)
(* *)
(* Purpose: Sends break signal over communications port *)
(* *)
(* Calling Sequence: *)
(* *)
(* Async_Send_Break; *)
(* *)
(* Calls: None *)
(* *)
(*----------------------------------------------------------------------*)
VAR
Old_Lcr : BYTE;
Break_Lcr : BYTE;
BEGIN (* Async_Send_Break *)
Old_Lcr := Port[ UART_LCR + Async_Base ];
Break_Lcr := Old_Lcr;
IF Break_Lcr > 127 THEN Break_Lcr := Break_Lcr - 128;
IF Break_Lcr <= 63 THEN Break_Lcr := Break_Lcr + 64;
Port[ UART_LCR + Async_Base ] := Break_Lcr;
DELAY( Async_Break_Length * 10 );
Port[ UART_LCR + Async_Base ] := Old_Lcr;
END (* Async_Send_Break *);
(*----------------------------------------------------------------------*)
(* Async_Send_String --- Send string over communications port *)
(*----------------------------------------------------------------------*)
PROCEDURE Async_Send_String( S : AnyStr );
(*----------------------------------------------------------------------*)
(* *)
(* Procedure: Async_Send_String *)
(* *)
(* Purpose: Sends string out over communications port *)
(* *)
(* Calling Sequence: *)
(* *)
(* Async_Send_String( S : AnyStr ); *)
(* *)
(* S --- String to send *)
(* *)
(* Calls: Async_Send *)
(* *)
(*----------------------------------------------------------------------*)
VAR
I : INTEGER;
BEGIN (* Async_Send_String *)
FOR I := 1 TO LENGTH( S ) DO
Async_Send( S[I] )
END (* Async_Send_String *);
(*----------------------------------------------------------------------*)
(* Async_Send_String_With_Delays --- Send string with timed delays *)
(*----------------------------------------------------------------------*)
PROCEDURE Async_Send_String_With_Delays( S : AnyStr;
Char_Delay : INTEGER;
EOS_Delay : INTEGER );
(*----------------------------------------------------------------------*)
(* *)
(* Procedure: Async_Send_String_With_Delays *)
(* *)
(* Purpose: Sends string out over communications port with *)
(* specified delays for each character and at the *)
(* end of the string. *)
(* *)
(* Calling Sequence: *)
(* *)
(* Async_Send_String_With_Delays( S : AnyStr ; *)
(* Char_Delay : INTEGER; *)
(* EOS_Delay : INTEGER ); *)
(* *)
(* S --- String to send *)
(* Char_Delay --- Number of milliseconds to delay after *)
(* sending each character *)
(* EOS_Delay --- Number of milleseconds to delay after *)
(* sending last character in string *)
(* *)
(* Calls: Async_Send *)
(* Async_Send_String *)
(* Length *)
(* Delay *)
(* *)
(* Remarks: *)
(* *)
(* This routine is useful when writing routines to perform *)
(* non-protocol uploads. Many computer systems require delays *)
(* between receipt of characters for correct processing. The *)
(* delay for end-of-string usually applies when the string *)
(* represents an entire line of a file. *)
(* *)
(* If delays are not required, Async_Send_String is faster. *)
(* This routine will call Async_Send_String is no character *)
(* delay is to be done. *)
(* *)
(*----------------------------------------------------------------------*)
VAR
I : INTEGER;
BEGIN (* Async_Send_String_With_Delays *)
IF Char_Delay <= 0 THEN
Async_Send_String( S )
ELSE
FOR I := 1 TO LENGTH( S ) DO
BEGIN
Async_Send( S[I] );
Delay( Char_Delay );
END;
IF EOS_Delay > 0 THEN Delay( EOS_Delay );
END (* Async_Send_String_With_Delays *);
(*----------------------------------------------------------------------*)
(* Async_Percentage_Used --- Report Percentage Buffer Filled *)
(*----------------------------------------------------------------------*)
FUNCTION Async_Percentage_Used : REAL;
(*----------------------------------------------------------------------*)
(* *)
(* Function: Async_Percent_Used *)
(* *)
(* Purpose: Reports percentage of com buffer currently filled *)
(* *)
(* Calling Sequence: *)
(* *)
(* Percentage := Async_Percentage_Used : Real; *)
(* *)
(* Percentage gets how much of buffer is filled; *)
(* value goes from 0.0 (empty) to 1.0 (totally full). *)
(* *)
(* Calls: None *)
(* *)
(* Remarks: *)
(* *)
(* This routine is helpful when incorporating handshaking into *)
(* a communications program. For example, assume that the host *)
(* computer uses the XON/XOFF (DC1/DC3) protocol. Then the *)
(* PC program should issue an XOFF to the host when the value *)
(* returned by Async_Percentage_Used > .75 or so. When the *)
(* utilization percentage drops below .25 or so, the PC program *)
(* should transmit an XON. *)
(* *)
(*----------------------------------------------------------------------*)
BEGIN (* Async_Percentage_Used *)
Async_Percentage_Used := Async_Buffer_Used / ( Async_Buffer_Size + 1 );
END (* Async_Percentage_Used *);
(*----------------------------------------------------------------------*)
(* Async_Purge_Buffer --- Purge communications input buffer *)
(*----------------------------------------------------------------------*)
PROCEDURE Async_Purge_Buffer;
(*----------------------------------------------------------------------*)
(* *)
(* Procedure: Async_Purge_Buffer *)
(* *)
(* Purpose: Purges communications input buffer *)
(* *)
(* Calling Sequence: *)
(* *)
(* Async_Purge_Buffer; *)
(* *)
(* Calls: Async_Receive *)
(* *)
(*----------------------------------------------------------------------*)
VAR
C: CHAR;
L: INTEGER;
BEGIN (* Async_Purge_Buffer *)
L := 10000 DIV Async_Baud_Rate;
IF L <= 0 THEN
L := 3;
REPEAT
DELAY( L )
UNTIL ( NOT Async_Receive( C ) );
END (* Async_Purge_Buffer *);
(*----------------------------------------------------------------------*)
(* Async_Peek --- Peek ahead in communications buffer *)
(*----------------------------------------------------------------------*)
FUNCTION Async_Peek( Nchars : INTEGER ) : CHAR;
(*----------------------------------------------------------------------*)
(* *)
(* Function: Async_Peek *)
(* *)
(* Purpose: Peeks ahead in comm buffer *)
(* *)
(* Calling Sequence: *)
(* *)
(* Ch := Async_Peek( NChars: INTEGER) : CHAR; *)
(* *)
(* NChars --- # of characters to peek ahead *)
(* Ch --- returned (peeked) character *)
(* *)
(* Calls: None *)
(* *)
(*----------------------------------------------------------------------*)
VAR
I: INTEGER;
BEGIN (* Async_Peek *)
I := ( Async_Buffer_Tail + NChars ) MOD Async_Buffer_Size;
IF ( I > Async_Buffer_Head ) THEN
Async_Peek := CHR( 0 )
ELSE
Async_Peek := Async_Buffer_Ptr^[ I ];
END (* Async_Peek *);
(*----------------------------------------------------------------------*)
(* Async_Setup_Port --- Setup port address and IRQ line *)
(*----------------------------------------------------------------------*)
PROCEDURE Async_Setup_Port( ComPort : INTEGER;
Base_Address : INTEGER;
IRQ_Line : INTEGER;
RS_232_Base : INTEGER );
(*----------------------------------------------------------------------*)
(* *)
(* Procedure: Async_Setup_Port *)
(* *)
(* Purpose: Sets up port address and IRQ line *)
(* *)
(* Calling Sequence: *)
(* *)
(* Async_Setup_Port( ComPort : INTEGER; *)
(* Base_Address : INTEGER; *)
(* IRQ_Line : INTEGER; *)
(* RS_232_Base : INTEGER ); *)
(* *)
(* ComPort --- which port (1 though MaxComPorts) *)
(* Base_Address --- Base address of port *)
(* IRQ_Line --- IRQ line for interrupts for port *)
(* RS_232_Base --- RS 232 base address for port *)
(* *)
(* Calls: None *)
(* *)
(*----------------------------------------------------------------------*)
BEGIN (* Async_Setup_Port *)
IF ( ( ComPort > 0 ) AND ( ComPort <= MaxComPorts ) ) THEN
BEGIN
Com_Base [ComPort] := Base_Address;
Com_Irq [ComPort] := IRQ_Line;
Com_RS232[ComPort] := RS_232_Base;
END;
END (* Async_Setup_Port *);
(*----------------------------------------------------------------------*)
(* Async_Release_Buffers --- Release buffers for serial ports *)
(*----------------------------------------------------------------------*)
PROCEDURE Async_Release_Buffers;
(*----------------------------------------------------------------------*)
(* *)
(* Procedure: Async_Release_Buffers; *)
(* *)
(* Purpose: Releases send and receive buffers *)
(* *)
(* Calling Sequence: *)
(* *)
(* Async_Release_Buffers; *)
(* *)
(* Calls: None *)
(* *)
(*----------------------------------------------------------------------*)
BEGIN (* Async_Release_Buffers *)
(* If port open, close it down first. *)
IF Async_Open_Flag THEN
Async_Close( FALSE );
FREEMEM( Async_Buffer_Ptr , Async_Buffer_Size + 1 );
FREEMEM( Async_OBuffer_Ptr , Async_OBuffer_Size + 1 );
END (* Async_Release_Buffers *);
(*----------------------------------------------------------------------*)
(* Async_Flush_Output_Buffer --- Flush output buffer for serial port *)
(*----------------------------------------------------------------------*)
PROCEDURE Async_Flush_Output_Buffer;
(*----------------------------------------------------------------------*)
(* *)
(* Procedure: Async_Flush_Output_Buffer; *)
(* *)
(* Purpose: Flushes output buffer for serial port. *)
(* *)
(* Calling Sequence: *)
(* *)
(* Async_Flush_Output_Buffer; *)
(* *)
(* Calls: None *)
(* *)
(*----------------------------------------------------------------------*)
BEGIN (* Async_Flush_Output_Buffer *)
Async_OBuffer_Head := Async_OBuffer_Tail;
Async_OBuffer_Used := 0;
END (* Async_Flush_Output_Buffer *);
(*----------------------------------------------------------------------*)
(* Async_Drain_Output_Buffer --- Wait for output buffer to drain *)
(*----------------------------------------------------------------------*)
PROCEDURE Async_Drain_Output_Buffer( Max_Wait_Time : INTEGER );
(*----------------------------------------------------------------------*)
(* *)
(* Procedure: Async_Drain_Output_Buffer; *)
(* *)
(* Purpose: Waits for output buffer to drain. *)
(* *)
(* Calling Sequence: *)
(* *)
(* Async_Drain_Output_Buffer( Max_Wait_Time : INTEGER ); *)
(* *)
(* Max_Wait_Time --- Maximum # of seconds to wait for *)
(* output buffer to drain. *)
(* *)
(* Calls: None *)
(* *)
(*----------------------------------------------------------------------*)
VAR
T1 : REAL;
BEGIN (* Async_Drain_Output_Buffer *)
T1 := TimeOfDay;
WHILE( ( Async_OBuffer_Head <> Async_OBuffer_Tail ) AND
( TimeDiff( T1 , TimeOfDay ) <= Max_Wait_Time ) ) DO
GiveAwayTime( 1 );
END (* Async_Drain_Output_Buffer *);
