'-----------------------------------------------------------------------------------------
'name : serint.bas
'copyright : (c) 1995-2005, MCS Electronics
'purpose : serial interrupt example for AVR
'micro : 90S8535
'suited for demo : yes
'commercial addon needed : no
'-----------------------------------------------------------------------------------------
 
$regfile = "8535def.dat" ' specify the used micro
$crystal = 4000000 ' used crystal frequency
$baud = 19200 ' use baud rate
$hwstack = 32 ' default use 32 for the hardware stack
$swstack = 10 ' default use 10 for the SW stack
$framesize = 40 ' default use 40 for the frame space
 
Const Cmaxchar = 20 'number of characters
 
Dim B As Bit 'a flag for signalling a received character
Dim Bc As Byte 'byte counter
Dim Buf As String * Cmaxchar 'serial buffer
Dim D As Byte
 
'Buf = Space(20)
'unremark line above for the MID() function in the ISR
'we need to fill the buffer with spaces otherwise it will contain garbage
 
Print "Start"
 
On Urxc Rec_isr 'define serial receive ISR
Enable Urxc 'enable receive isr
 
 
 
Enable Interrupts 'enable interrupts to occur
 
Do
If B = 1 Then 'we received something
 Disable Serial
 Print Buf 'print buffer
 Print Bc 'print character counter
 
 
 'now check for buffer full
 If Bc = Cmaxchar Then 'buffer full
 Buf = "" 'clear
 Bc = 0 'rest character counter
 End If
 
 Reset B 'reset receive flag
 Enable Serial
End If
Loop
 
Rec_isr:
Print "*"
If Bc < Cmaxchar Then 'does it fit into the buffer?
 Incr Bc 'increase buffer counter
 
 
 If Udr = 13 Then 'return?
 Buf = Buf + Chr(0)
 Bc = Cmaxchar
 Else
 Buf = Buf + Chr(udr) 'add to buffer
 End If
 
 
 ' Mid(buf , Bc , 1) = Udr
 'unremark line above and remark the line with Chr() to place
 'the character into a certain position
 'B = 1 'set flag
End If
B = 1 'set flag
Return