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C/C++ Users Group Library 1996 July
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C-C++ Users Group Library July 1996.iso
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v_03_04
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3n04042a
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1992-02-06
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930b
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40 lines
LISTING 1
/* -------------- timer.h --------------- */
/*
command byte
D7 D6 D5 D4 D3 D2 D1 D0
SC1 SC0 RL1 RL0 M2 M1 M0 BCD
SC counter 00,01,10
00 counter 0
01 not used ( counter 1 command addr is different)
10 counter 2
RL r/w latch command
00 latch (needed for 16 bits)
01 read/write lsb
10 read/write msb
11 read/write both
M mode (usually)
mode 3 011 square wave or
mode 2 010 rate generator
BCD 1 for bcd 0 for binary
*/
/* don't mess with timer1 - ram refresh - */
#define TIMER0 0x40
#define TIMER2 0x42
#define TIMERC 0x43
#define TMODE2 0x34
#define RHBTIM0 0 /* read high byte of timer 0 */
#define PIC01 0x21 /* 8259A mask register */
#define PIC00 0x20 /* 8259A command register */
#define EOI 0x20 /* end of interrupt cmd */
#define OCW3IR 0x0a /* next read is pending
request register on either port */