mc68hc05bs8 Freescale Semiconductor, Inc, mc68hc05bs8 Datasheet - Page 25

• Manufacturer Part Number: mc68hc05bs8
• Description: Mc68hc05 Family Of Low-cost Single-chip Microcontrollers.
• Manufacturer: Freescale Semiconductor, Inc

The interrupt signal is latched, and it should be cleared by writing a “1” to the KBIC bit in the KBI
register (bit 6 of $001E) in the interrupt service routine. This should be cleared after the key is
debounced, otherwise unwanted keyboard interrupt signals may be generated.
The keyboard interrupt is negative-edge sensitive only, and the interrupt service routine is
specified by the contents of the memory locations $3FF0 and $3FF1.
KBIC - Keyboard Interrupt Clear
KBE5:0 - Keyboard Interrupt Enable 5:0
3.5
PC6 and PC7 are used for SDA and SDL respectively when configured for the software supported
M-Bus interface. This M-Bus interface is operated by software emulation, with hardware interrupt
circuit connected to PC6 and PC7.
MC68HC05BS8
1 (set)
1 (set)
0 (clear) –
KBI Register
PC6 and PC7 - Software Supported M-Bus SDA and SCL
–
–
Clear keyboard interrupt latch.
Enable keyboard interrupt for the corresponding bit.
Disable keyboard interrupt for the corresponding bit.
Address bit 7
$001E
INPUT/OUTPUT PORTS
KBIC
bit 6
KBE5 KBE4 KBE3 KBE2 KBE1 KBE0 0000 0000
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
on reset
State
TPG
3