SMART Embedded Computing MVME2502, Инструкция по установке и эксплуатации

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Memory Maps and Registers
MVME2502 Installation and Use (6806800R96L) 115
5.6.2 Control Registers
5.6.3 Compare High and Low Word Registers
The tick timer counter is compared to the Compare Register. When the values are equal,
the tick timer interrupt is asserted and the overflow counter increments. If the clear-on-
compare mode is enabled, the counter is also cleared. For periodic interrupts, this equation
should be used to calculate the compare value for a specific period (T):
Compare register value=T (us)
Table 5-26 Control Registers
REG
Tick Timer 0 Control Register - 0xFFC80202
Tick Timer 1 Control Register - 0xFFC80302
Tick Timer 2 Control Register - 0xFFC80402
Bit 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Field
RSVD INTS CINT ENINT OVF RSVD COVF COC ENC
OPER R/W
RESET 0x0000
Field Description
ENC Enable counter. When the bit is set, the counter increments. When the bit is
cleared, the counter does not increment.
COC Clear Counter on Compare. When the bit is set, the counter is reset to 0
when it compares with the compare register. When the bit is cleared the
counter is not reset.
COVF Clear Overflow Bits. The overflow counter is cleared when 1 is written to this
bit.
OVF Overflow Bits are the output of the overflow counter. It increments each time
the tick timer sends an interrupt to the local bus interrupter. The overflow
counter is cleared by writing 1 to the COVF bit.
ENINT Enable Interrupt. When the bit is set, the interrupt is enabled. When the bit
is cleared, the interrupt is not enabled.
CINT Clear Interrupt.
INTS Interrupt Status.
RSVD Reserved for future implementation.