mc68hc11ea9 Freescale Semiconductor, Inc, mc68hc11ea9 Datasheet - Page 39

• Manufacturer Part Number: mc68hc11ea9
• Description: 8-bit Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

TMSK2 — Timer Interrupt Mask 2
TOI — Timer Overflow Interrupt Enable
RTII — Real-Time Interrupt Enable
PAOVI — Pulse Accumulator Overflow Interrupt Enable
PAII — Pulse Accumulator Input Edge Interrupt Enable
Bits [3:2] — Not Implemented
PR[1:0] — Timer Prescaler Select
MC68HC11EA9
MC68HC11EA9TS/D
RESET:
Bits [7:4] can be written at any time. PR[1:0] can only be written once in the first 64 cycles after reset in
normal modes (SMOD = 0). In special modes (SMOD = 1) PR[1:0] can be written any time.
If the TOI enable bit is set when the value in the timer counter register (TCNT) changes from $FFFF to
$0000, an interrupt is generated.
If RTII enable bit is set, interrupts are generated at the rate determined by the real-time interrupt rate
(RTR[1:0]) bits in PACTL.
If the PAOVI enable bit is set when the pulse accumulator counter register (PACNT) changes from
$FFFF to $0000 an interrupt is generated.
If the PAII enable bit is set when an edge (rising or falling, depending on configuration) is detected on
the pulse accumulator input pin (PA7/PAI), an interrupt is generated.
Always read zero
0 = Timer overflow interrupts disabled
1 = Interrupts are generated each time TCNT rolls over to $0000
0 = Periodic interrupts are disabled
1 = Interrupts are generated at the rate determined by RTR[1:0]
0 = PCNT overflow interrupts are disabled
1 = Interrupts are generated each time PCNT rolls over to $0000
0 = Interrupts from edges on PAI pin are disabled
1 = Edges detected on PAI pin generate interrupts (rising or falling, depending on configuration)
BIT 7
TOI
0
RTII
6
0
Freescale Semiconductor, Inc.
For More Information On This Product,
PR1
Table 16 Main Timer Prescaler Selection
0
0
1
1
PAOVI
5
0
PR0
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0
1
0
1
PAII
4
0
Prescaler Selected
—
3
0
16
1
4
8
—
2
0
PR1
1
0
BIT 0
PR0
0
$1024
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