MC68HC711E20CFN3 Freescale Semiconductor, MC68HC711E20CFN3 Datasheet - Page 199

• Manufacturer Part Number: MC68HC711E20CFN3
• Description: IC MCU 3MHZ 20K OTP 52-PLCC
• Manufacturer: Freescale Semiconductor
• Series: HC11r

Specifications of MC68HC711E20CFN3

• Core Processor: HC11
• Core Size: 8-Bit
• Speed: 3MHz
• Connectivity: SCI, SPI
• Peripherals: POR, WDT
• Number Of I /o: 38
• Program Memory Size: 20KB (20K x 8)
• Program Memory Type: OTP
• Eeprom Size: 512 x 8
• Ram Size: 768 x 8
• Voltage - Supply (vcc/vdd): 4.5 V ~ 5.5 V
• Data Converters: A/D 8x8b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 52-PLCC
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

9.6 Real-Time Interrupt (RTI)
M68HC11E Family — Rev. 3.2
MOTOROLA
The real-time interrupt (RTI) feature, used to generate hardware
interrupts at a fixed periodic rate, is controlled and configured by two bits
(RTR1 and RTR0) in the pulse accumulator control (PACTL) register.
The RTII bit in the TMSK2 register enables the interrupt capability. The
four different rates available are a product of the MCU oscillator
frequency and the value of bits RTR[1:0]. Refer to
shows the periodic real-time interrupt rates.
The clock source for the RTI function is a free-running clock that cannot
be stopped or interrupted except by reset. This clock causes the time
between successive RTI timeouts to be a constant that is independent
of the software latencies associated with flag clearing and service. For
this reason, an RTI period starts from the previous timeout, not from
when RTIF is cleared.
Every timeout causes the RTIF bit in TFLG2 to be set, and if RTII is set,
an interrupt request is generated. After reset, one entire RTI period
elapses before the RTIF is set for the first time. Refer to the
Interrupt Mask 2
9.6.3 Pulse Accumulator Control
RTR[1:0]
0 0
0 1
1 0
1 1
E = 3 MHz
10.923 ms
21.845 ms
2.731 ms
5.461 ms
Timing System
Register,
Table 9-5. RTI Rates
9.6.2 Timer Interrupt Flag Register
E = 2 MHz
16.384 ms
32.768 ms
4.096 ms
8.192 ms
Register.
E = 1 MHz
16.384 ms
32.768 ms
65.536 ms
8.192 ms
Real-Time Interrupt (RTI)
Table
9-5, which
Timing System
Technical Data
9.5.9 Timer
E = X MHz
(E/2
(E/2
(E/2
(E/2
13
14
15
16
2, and
)
)
)
)
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