SECTION 6
Conversions and Interfaces
PEN*KEY
R
6200/6300 Hand-Held Computer Programmer’s Reference Guide 6-71
INT 15h, Function AX = 01F5h: Exchange Network Packets
4000API
Accesses BIOS Media ACcess (MAC) layer for sending and receiving network
packets. Set COM channel for proper communication rate, parity, bits before
making this call.
This system service may not be PC compatible.
On Entry:
AH = 01h
AL = 0F5h
ES:BX = Pointer to cbuf to receive
DS:DI = Pointer to cbuf to send
DL = COM port (0 or 1)
CX = Timeout value in milliseconds for send, receive
On Return:
AX = Undefined
DX = Undefined
CX = +Length or ćError
ć21 = Packet too long for this address
ć41 = CRC error in packet for this address
ćA1 = Timeout, transmit operation incomplete
ćB1 = Timeout, receive macro service has stalled
ćC1 = Timeout, transmit complete, no receive activity
ćFF = Timeout, receive activity
Code fragment:
cbuf struc
dd ? ; BIOS scratch area
db ? ; unused by BIOS
db ? ; BIOS scratch area
len
dw ? ; length of buffer data
dw ? ; BIOS scratch area
adr
db ? ; network address
dw ? ; BIOS scratch area
ctl
db ? ; frame control field
buffer db ? ; dup(?); frame i-field buffer
dw ? ; BIOS scratch area
cbuf ends
INT 15h, Function AX = 01F8h: Adjust CX for Processor Speed
4000API
Programs that use software timing loops should use this function to adjust their
loop counts to match the processor speed. The input value of CX is assumed to
be the loop count for 4 Mhz operation (8 MHz crystal speed).
This system service
may not be PC compatible.
On Entry:
AH = 01h
AL = 0F8h
CX = Count value for 4 MHz operation
On Return:
CX = Adjusted count value for current processor speed
Zero = 0 = No counter underflow value
1 = Counter value underflowed
Carry = 0 = No counter overflow value
1 = Counter value overflowed
6. Conversions and
Interfaces
