Compaq Contec COM-2(PC)F - Manual (Page 68)

Appendix
COM-2(PC)F
59
Example program (for accessing an i8254 or equivalent)
- Microsoft Macro Assembler
OUT DX, AL ; Access to the i8254
IN AL, 2EFH ; Execute IN AL, 2EFH once to provide
the recovery time
- Microsoft C/C++
outp(port, byte); /* Access to the i8254 */
rt=inp(0x2ef); /* Execute rt=inp(0x2ef); once to
provide the recovery time */