National Instruments PC-DIO-96, User Manual

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Appendix A Specifications
© National Instruments Corporation A-3 PC-DIO-96 User Manual
Table A-1. Maximum Average Transfer Rates for the PC-DIO-96
Bus CPU CPU Speed Assembly C
AT (ISA16) 486DX4 100 MHz 490 kbytes/s 470 kbytes/s
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
dec cx ; Decrement the loop counter
jnz short loop ; See if we need to loop
C code:
address = 0x0180; /* The port address */
for (i = 0; i < 64; i++) { /* Loop 64 times */
outp(address, *data++); /* Send data */
}