MC68HC811E2FN Freescale Semiconductor, MC68HC811E2FN Datasheet - Page 87

• Manufacturer Part Number: MC68HC811E2FN
• Manufacturer: Freescale Semiconductor

Specifications of MC68HC811E2FN

• Cpu Family: HC11
• Device Core Size: 8b
• Frequency (max): 4MHz
• Interface Type: SCI/SPI
• Program Memory Type: ROMLess
• Program Memory Size: Not Required
• Total Internal Ram Size: 256Byte
• # I/os (max): 38
• Number Of Timers - General Purpose: 8
• Operating Supply Voltage (typ): 3.3/5V
• Operating Supply Voltage (max): 5.5V
• Operating Supply Voltage (min): 3V
• On-chip Adc: 8-chx8-bit
• Instruction Set Architecture: CISC
• Operating Temp Range: 0C to 70C
• Operating Temperature Classification: Commercial
• Mounting: Surface Mount
• Pin Count: 52
• Package Type: PLCC
• Lead Free Status / Rohs Status: Supplier Unconfirmed

5.5 Interrupts
The MCU has 18 interrupt vectors that support 22 interrupt sources. The 15 maskable interrupts are
generated by on-chip peripheral systems. These interrupts are recognized when the global interrupt mask
bit (I) in the condition code register (CCR) is clear. The three non-maskable interrupt sources are illegal
opcode trap, software interrupt, and XIRQ pin. Refer to
vector assignments for each source.
For some interrupt sources, such as the SCI interrupts, the flags are automatically cleared during the
normal course of responding to the interrupt requests. For example, the RDRF flag in the SCI system is
cleared by the automatic clearing mechanism consisting of a read of the SCI status register while RDRF
is set, followed by a read of the SCI data register. The normal response to an RDRF interrupt request
would be to read the SCI status register to check for receive errors, then to read the received data from
the SCI data register. These steps satisfy the automatic clearing mechanism without requiring special
instructions.
Freescale Semiconductor
PSEL[3:0]
Table 5-3. Highest Priority Interrupt Selection
0 0 0 0
0 0 0 1
0 0 1 0
0 0 1 1
0 1 0 0
0 1 0 1
0 1 1 0
0 1 1 1
1 0 0 0
1 0 0 1
1 0 1 0
1 0 1 1
1 1 0 0
1 1 0 1
1 1 1 0
1 1 1 1
M68HC11E Family Data Sheet, Rev. 5.1
Timer overflow
Pulse accumulator overflow
Pulse accumulator input edge
SPI serial transfer complete
SCI serial system
Reserved (default to IRQ)
IRQ (external pin or parallel I/O)
Real-time interrupt
Timer input capture 1
Timer input capture 2
Timer input capture 3
Timer output compare 1
Timer output compare 2
Timer output compare 3
Timer output compare 4
Timer input capture 4/output compare 5
Interrupt Source Promoted
Table
5-4, which shows the interrupt sources and
Interrupts
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