MC908JB8ADWE Freescale Semiconductor, MC908JB8ADWE Datasheet - Page 222

• Manufacturer Part Number: MC908JB8ADWE
• Description: IC MCU 3MHZ 8K FLASH 28-SOIC
• Manufacturer: Freescale Semiconductor
• Series: HC08r

Specifications of MC908JB8ADWE

• Core Processor: HC08
• Core Size: 8-Bit
• Speed: 3MHz
• Connectivity: USB
• Peripherals: LVD, POR, PWM
• Number Of I /o: 21
• Program Memory Size: 8KB (8K x 8)
• Program Memory Type: FLASH
• Ram Size: 256 x 8
• Voltage - Supply (vcc/vdd): 4 V ~ 5.5 V
• Oscillator Type: Internal
• Operating Temperature: 0°C ~ 70°C
• Package / Case: 28-SOIC (7.5mm Width)
• Processor Series: HC08JB
• Core: HC08
• Data Bus Width: 8 bit
• Data Ram Size: 256 B
• Interface Type: USB
• Maximum Clock Frequency: 3 MHz
• Number Of Programmable I/os: 37
• Number Of Timers: 2
• Operating Supply Voltage: 5.25 V
• Maximum Operating Temperature: + 70 C
• Mounting Style: SMD/SMT
• Development Tools By Supplier: FSICEBASE, DEMO908GZ60E, M68EML08GZE, KITUSBSPIDGLEVME, KITUSBSPIEVME, KIT33810EKEVME
• Minimum Operating Temperature: 0 C
• Controller Family/series: HC08
• No. Of I/o's: 21
• Ram Memory Size: 256Byte
• Cpu Speed: 8MHz
• No. Of Timers: 1
• Embedded Interface Type: SCI, SPI
• Rohs Compliant: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Data Converters: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

External Interrupt (IRQ)
13.5 IRQ Pin
Technical Data
222
The IRQ pin has a low leakage for input voltages ranging from 0V to
V
the MCU.
A logic 0 on the IRQ pin can latch an interrupt request into the IRQ latch.
A vector fetch, software clear, or reset clears the IRQ latch.
If the MODE bit is set, the IRQ pin is both falling-edge-sensitive and low-
level-sensitive. With MODE set, both of the following actions must occur
to clear IRQ:
The vector fetch or software clear and the return of the IRQ pin to logic
one may occur in any order. The interrupt request remains pending as
long as the IRQ pin is at logic zero. A reset will clear the latch and the
MODE control bit, thereby clearing the interrupt even if the pin stays low.
If the MODE bit is clear, the IRQ pin is falling-edge-sensitive only. With
MODE clear, a vector fetch or software clear immediately clears the IRQ
latch.
The IRQF bit in the ISCR register can be used to check for pending
interrupts. The IRQF bit is not affected by the IMASK bit, which makes it
useful in applications where polling is preferred.
DD
•
•
; suitable for applications using RC discharge circuitry to wake up
Vector fetch or software clear — A vector fetch generates an
interrupt acknowledge signal to clear the latch. Software may
generate the interrupt acknowledge signal by writing a logic 1 to
the ACK bit in the interrupt status and control register (ISCR). The
ACK bit is useful in applications that poll the IRQ pin and require
software to clear the IRQ latch. Writing to the ACK bit prior to
leaving an interrupt service routine can also prevent spurious
interrupts due to noise. Setting ACK does not affect subsequent
transitions on the IRQ pin. A falling edge that occurs after writing
to the ACK bit latches another interrupt request. If the IRQ mask
bit, IMASK, is clear, the CPU loads the program counter with the
vector address at locations $FFF8 and $FFF9.
Return of the IRQ pin to logic one — As long as the IRQ pin is at
logic zero, IRQ remains active.
External Interrupt (IRQ)
MC68HC908JB8•MC68HC08JB8•MC68HC08JT8 — Rev. 2.3
Freescale Semiconductor