MCR908JK1ECPE Freescale Semiconductor, MCR908JK1ECPE Datasheet - Page 118

• Manufacturer Part Number: MCR908JK1ECPE
• Description: IC MCU 1.5K FLASH 8MHZ 20-DIP
• Manufacturer: Freescale Semiconductor
• Series: HC08r

Specifications of MCR908JK1ECPE

• Core Processor: HC08
• Core Size: 8-Bit
• Speed: 8MHz
• Peripherals: LED, LVD, POR, PWM
• Number Of I /o: 14
• Program Memory Size: 1.5KB (1.5K x 8)
• Program Memory Type: FLASH
• Ram Size: 128 x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 3.3 V
• Data Converters: A/D 12x8b
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 20-DIP (0.300", 7.62mm)
• Processor Series: HC08JK
• Core: HC08
• Data Bus Width: 8 bit
• Data Ram Size: 128 B
• Maximum Clock Frequency: 8 MHz
• Number Of Programmable I/os: 15
• Number Of Timers: 2
• Maximum Operating Temperature: + 85 C
• Mounting Style: Through Hole
• Development Tools By Supplier: FSICEBASE, DEMO908JL16E, M68CBL05CE
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 8 bit, 12 Channel
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Connectivity: -
• Lead Free Status / Rohs Status: Details

Keyboard Interrupt Module (KBI)
12.4 Functional Description
Writing to the KBIE6–KBIE0 bits in the keyboard interrupt enable register independently enables or
disables each port A pin as a keyboard interrupt pin. Enabling a keyboard interrupt pin in port A also
enables its internal pull-up device irrespective of PTAPUEx bits in the port A input pull-up enable register
(see
interrupt pin latches a keyboard interrupt request.
A keyboard interrupt is latched when one or more keyboard pins goes low after all were high. The MODEK
bit in the keyboard status and control register controls the triggering mode of the keyboard interrupt.
If the MODEK bit is set, the keyboard interrupt pins are both falling edge- and low level-sensitive, and both
of the following actions must occur to clear a keyboard interrupt request:
118
KBI0
KBI6
TO PULLUP ENABLE
TO PULLUP ENABLE
•
•
•
•
10.2.3 Port A Input Pull-up Enable Register
If the keyboard interrupt is edge-sensitive only, a falling edge on a keyboard pin does not latch an
interrupt request if another keyboard pin is already low. To prevent losing an interrupt request on
one pin because another pin is still low, software can disable the latter pin while it is low.
If the keyboard interrupt is falling edge- and low level-sensitive, an interrupt request is present as
long as any keyboard pin is low.
Vector fetch or software clear — A vector fetch generates an interrupt acknowledge signal to clear
the interrupt request. Software may generate the interrupt acknowledge signal by writing a 1 to the
ACKK bit in the keyboard status and control register KBSCR. The ACKK bit is useful in applications
that poll the keyboard interrupt pins and require software to clear the keyboard interrupt request.
Writing to the ACKK bit prior to leaving an interrupt service routine can also prevent spurious
interrupts due to noise. Setting ACKK does not affect subsequent transitions on the keyboard
interrupt pins. A falling edge that occurs after writing to the ACKK bit latches another interrupt
request. If the keyboard interrupt mask bit, IMASKK, is clear, the CPU loads the program counter
with the vector address at locations $FFE0 and $FFE1.
Return of all enabled keyboard interrupt pins to logic 1 — As long as any enabled keyboard
interrupt pin is at 0, the keyboard interrupt remains set.
KBIE0
KBIE6
.
.
.
Figure 12-2. Keyboard Interrupt Block Diagram
MC68HC908JL3E Family Data Sheet, Rev. 4
MODEK
V
DD
D
CK
CLR
(PTAPUE)). A logic 0 applied to an enabled keyboard
Q
INTERRUPT FF
KEYBOARD
RESET
ACKK
VECTOR FETCH
INTERNAL BUS
DECODER
IMASKK
SYNCHRONIZER
Freescale Semiconductor
KEYF
KEYBOARD
INTERRUPT
REQUEST