mc68hc05ct4fn Freescale Semiconductor, Inc, mc68hc05ct4fn Datasheet - Page 82

• Manufacturer Part Number: mc68hc05ct4fn
• Description: Mc68hc05 Family Of Microcontrollers Mcus
• Manufacturer: Freescale Semiconductor, Inc

Core Timer
General Release Specification
TOFC — Timer Overflow Flag Clear
RTFC — Real-Time Interrupt Flag Clear
RT1 and RT0 — Real-Time Interrupt Rate Select
When a logic 1 is written to this bit, CTOF is cleared. Writing a logic 0
has no effect on the CTOF bit. This bit always reads as zero.
When a logic 1 is written to this bit, RTIF is cleared. Writing a logic 0
has no effect on the RTIF bit. This bit always reads as zero.
These two bits select one of four taps from the real-time interrupt
circuit. See
slowest periodic rate and gives the maximum time in which to alter
these bits if necessary. Care should be taken when altering RT0 and
RT1 if the timeout period is imminent or uncertain. If the selected tap
is modified during a cycle in which the counter is switching, an RTIF
could be missed or an additional one could be generated. To avoid
problems, the COP should be cleared before changing RTI taps.
Freescale Semiconductor, Inc.
16 ms
32 ms
64 ms
8 ms
For More Information On This Product,
2.048 MHz
RTI Rate
Table 10-1. RTI and COP Rates at 2.048 MHz
Go to: www.freescale.com
Table
2
2
2
2
14
15
16
17
/E
/E
/E
/E
Core Timer
10-1. Reset sets these two bits, which selects the
and RT0
RT1
00
01
10
11
(2
(2
(2
(2
17
18
19
20
Minimum COP Rates
–2
–2
–2
–2
MC68HC05CT4
14
15
16
17
2.048 MHz
)/E
)/E
)/E
)/E
112 ms
224 ms
448 ms
—
56 ms
Rev. 2.0