MC68376BGMAB20 Freescale Semiconductor, MC68376BGMAB20 Datasheet - Page 129

• Manufacturer Part Number: MC68376BGMAB20
• Description: IC MCU 32BIT 8K ROM 160-QFP
• Manufacturer: Freescale Semiconductor
• Series: M683xxr

Specifications of MC68376BGMAB20

• Core Processor: CPU32
• Core Size: 32-Bit
• Speed: 20MHz
• Connectivity: CAN, EBI/EMI, SCI, SPI
• Peripherals: POR, PWM, WDT
• Number Of I /o: 18
• Program Memory Type: ROMless
• Ram Size: 7.5K x 8
• Voltage - Supply (vcc/vdd): 4.75 V ~ 5.25 V
• Data Converters: A/D 16x10b
• Oscillator Type: External
• Operating Temperature: -40°C ~ 125°C
• Package / Case: 160-QFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Program Memory Size: -

5.8.2 Interrupt Priority and Recognition
MC68336/376
USER’S MANUAL
At the release of reset, the exception vector table is located beginning at address
$000000. This value can be changed by programming the vector base register (VBR)
with a new value. Multiple vector tables can be used. Refer to 4.9 Exception Process-
ing for more information.
The CPU32 provides seven levels of interrupt priority (1-7), seven automatic interrupt
vectors, and 200 assignable interrupt vectors. All interrupts with priorities less than
seven can be masked by the interrupt priority (IP) field in status register.
There are seven interrupt request signals (IRQ[7:1]). These signals are used internally
on the IMB, and have corresponding pins for external interrupt service requests. The
CPU32 treats all interrupt requests as though they come from internal modules; exter-
nal interrupt requests are treated as interrupt service requests from the SIM. Each of
the interrupt request signals corresponds to an interrupt priority. IRQ1 has the lowest
priority and IRQ7 the highest.
Interrupt recognition is determined by interrupt priority level and interrupt priority (IP)
mask value. The interrupt priority mask consists of three bits in the CPU32 status reg-
ister. Binary values %000 to %111 provide eight priority masks. Masks prevent an in-
terrupt request of a priority less than or equal to the mask value from being recognized
and processed. IRQ7, however, is always recognized, even if the mask value is %111.
IRQ[7:1] are active-low level-sensitive inputs. The low on the pin must remain asserted
until an interrupt acknowledge cycle corresponding to that level is detected.
IRQ7 is transition-sensitive as well as level-sensitive: a level-7 interrupt is not detected
unless a falling edge transition is detected on the IRQ7 line. This prevents redundant
servicing and stack overflow. A non-maskable interrupt is generated each time IRQ7
is asserted as well as each time the priority mask is written while IRQ7 is asserted. If
IRQ7 is asserted and the IP mask is written to any new value (including %111), IRQ7
will be recognized as a new IRQ7.
Interrupt requests are sampled on consecutive falling edges of the system clock. In-
terrupt request input circuitry has hysteresis. To be valid, a request signal must be as-
serted for at least two consecutive clock periods. Valid requests do not cause
immediate exception processing, but are left pending. Pending requests are pro-
cessed at instruction boundaries or when exception processing of higher-priority
interrupts is complete.
Exceptions such as “address error” are not interrupts and have no
“level” associated. Exceptions cannot ever be masked.
SYSTEM INTEGRATION MODULE
NOTE
MOTOROLA
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