MC68HC908LB8CPE Freescale Semiconductor, MC68HC908LB8CPE Datasheet - Page 178

• Manufacturer Part Number: MC68HC908LB8CPE
• Description: IC MCU 8K FLASH 8MHZ 20DIP
• Manufacturer: Freescale Semiconductor
• Series: HC08r

Specifications of MC68HC908LB8CPE

• Core Processor: HC08
• Core Size: 8-Bit
• Speed: 8MHz
• Peripherals: LVR, POR, PWM
• Number Of I /o: 18
• Program Memory Size: 8KB (8K x 8)
• Program Memory Type: FLASH
• Ram Size: 128 x 8
• Voltage - Supply (vcc/vdd): 4.5 V ~ 5.5 V
• Data Converters: A/D 7x8b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 20-DIP (0.300", 7.62mm)
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Connectivity: -

System Integration Module (SIM)
Interrupts are latched, and arbitration is performed in the SIM at the start of interrupt processing. The
arbitration result is a constant that the CPU uses to determine which vector to fetch. Once an interrupt is
latched by the SIM, no other interrupt can take precedence, regardless of priority, until the latched
interrupt is serviced (or the I bit is cleared). See
17.5.1.1 Hardware Interrupts
A hardware interrupt does not stop the current instruction. Processing of a hardware interrupt begins after
completion of the current instruction. When the current instruction is complete, the SIM checks all pending
hardware interrupts. If interrupts are not masked (I bit clear in the condition code register) and if the
corresponding interrupt enable bit is set, the SIM proceeds with interrupt processing; otherwise, the next
instruction is fetched and executed.
If more than one interrupt is pending at the end of an instruction execution, the highest priority interrupt is
serviced first.
is pending upon exit from the original interrupt service routine, the pending interrupt is serviced before the
LDA instruction is executed.
178
INTERRUPT
I BIT
INTERRUPT
R/W
I BIT
IDB
R/W
IAB
IDB
IAB
MODULE
MODULE
Figure 17-11
DUMMY
DUMMY
SP – 4
SP
demonstrates what happens when two interrupts are pending. If an interrupt
PC – 1[7:0] PC – 1[15:8]
CCR
Figure 17-9. Interrupt Recovery Timing
Figure 17-8
SP – 3
SP – 1
MC68HC908LB8 Data Sheet, Rev. 1
A
SP – 2
SP – 2
.
Interrupt Entry Timing
X
X
Figure
SP – 1
SP – 3
PC – 1 [7:0] PC – 1 [15:8] OPCODE
17-10.
A
SP – 4
SP
CCR
VECT H
PC
V DATA H
PC + 1
VECT L
OPERAND
V DATA L
START ADDR
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