MC68HC908LD60IFU Freescale Semiconductor, MC68HC908LD60IFU Datasheet - Page 261

• Manufacturer Part Number: MC68HC908LD60IFU
• Manufacturer: Freescale Semiconductor

Specifications of MC68HC908LD60IFU

• Cpu Family: HC08
• Device Core Size: 8b
• Frequency (max): 6MHz
• Program Memory Type: Flash
• Program Memory Size: 60KB
• Total Internal Ram Size: 1KB
• # I/os (max): 39
• Number Of Timers - General Purpose: 2
• Operating Supply Voltage (typ): 3.3V
• Operating Supply Voltage (max): 3.6V
• Operating Supply Voltage (min): 3V
• On-chip Adc: 6-chx8-bit
• Instruction Set Architecture: CISC
• Operating Temp Range: 0C to 85C
• Operating Temperature Classification: Commercial
• Mounting: Surface Mount
• Pin Count: 64
• Package Type: PQFP
• Lead Free Status / Rohs Status: Compliant

19.6 Keyboard Initialization
19.7 I/O Registers
MC68HC908LD60
Freescale Semiconductor
—
Rev. 1.1
When a keyboard interrupt pin is enabled, it takes time for the pullup
device to reach a logic 1. Therefore, a false interrupt can occur as soon
as the pin is enabled.
To prevent a false interrupt on keyboard initialization:
An interrupt signal on an edge-triggered pin can be acknowledged
immediately after enabling the pin. An interrupt signal on an edge- and
level-triggered interrupt pin must be acknowledged after a delay that
depends on the external load.
Another way to avoid a false interrupt:
These registers control and monitor operation of the keyboard module:
1. Mask keyboard interrupts by setting the IMASKK bit in the
2. Enable the KBI pins by setting the appropriate KBIEx bits in the
3. Write to the ACKK bit in the keyboard status and control register
4. Clear the IMASKK bit.
1. Configure the keyboard pins as outputs by setting the appropriate
2. Write logic 1s to the appropriate port A data register bits.
3. Enable the KBI pins by setting the appropriate KBIEx bits in the
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•
keyboard status and control register.
keyboard interrupt enable register.
to clear any false interrupts.
DDRA bits in data direction register A.
keyboard interrupt enable register.
Keyboard status and control register (KBSCR)
Keyboard interrupt enable register (KBIER)
Keyboard Interrupt Module (KBI)
Keyboard Interrupt Module (KBI)
Keyboard Initialization
Technical Data
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