Appendix A
Specifications
DAQCard-DIO-24 User Manual
A-4
©
National Instruments Corporation
A 486 DX machine used was an NEC UltraLite VERSA laptop.
The 486 DX2 machine used was a desktop PC using the CARDport ISA
PCMCIA adapter.
Assembly language code:
mov
cx, 64
; Count out 64 transfers
mov
dx, 0180h
; The port to access
loop:
lodsb
; Assume ds:si points to buffer of data
out
dx, al
; Send the data
add
dx, 0014h
; Add offset to base address for Ireg1
in
al, dx
; Dummy read from Ireg1
sub
dx, 0014h
; Restore base address
; The previous four lines are not
; necessary for measuring transfer rates
dec
cx
; Decrement the loop counter
jnz
short loop
; See if we need to loop
C code:
address = 0x0180;
/* The port address */
ireg1address = a 0x0014;
for (i = 0; i < 64; i++) {
/* Loop 64 times */
outp(address, *data++);
/* Send data */
inp(ireg1address);
}
Table A-1.
DAQCard-DIO-24 Maximum Average Transfer Rates
Bus
CPU
CPU Speed
Assembly
C
AT (ISA16)
486
DX
33 MHz
254 kbytes/s
176 kbytes/s
AT (ISA16)
486
DX2
50 MHz
294 kbytes/s
213 kbytes/s
