MCMC68HC05L16 Freescale Semiconductor, Inc, MCMC68HC05L16 Datasheet - Page 19

• Manufacturer Part Number: MCMC68HC05L16
• Description: M68hc05 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

1.5.3.2 External Clock
An external clock from another CMOS-compatible device can be connected to the XOSC1 input, with the
XOSC2 input not connected, as shown in
the oscillator is set up.
1.5.4 RESET
This pin can be used as an input to reset the MCU to a known startup state by pulling it to the low state.
When power is removed, the RESET pin contains a steering diode to discharge any voltage on the pin to
V
internal RESET pin pullup resistor may be selected as a mask option. A typical pullup resistor value is 46
kΩ.
1.5.5 Port A (PA0–PA7)
Port A is an 8-bit I/O port. The state of any pin is software programmable and all port A lines are configured
as inputs during power-on or reset. Port A outputs may be configured as open-drain outputs and
connected to a pullup resistor by software option.
1.5.6 Port B (PB0–PB7/KWI0–KWI7)
Port B is an 8-bit input-only port that shares its lines with the key wakeup interrupt (KWI) system. Port B
has a pullup option by software option.
1.5.7 Port C (PC0/SDI, PC1/SDO, PC2/SCK, PC3/TCAP, PC4/EVI,
PC5/EVO, PC6/IRQ2, and PC7/IRQ1)
Port C is an 8-bit I/O port. The state of any pin is software programmable and all port C lines are
configured as inputs during power-on or reset. All port C lines may connect to a pullup resistor by software
option.
1.5.8 Port D (PD1–PD3/BP1–BP3 and PD4–PD7/FP34–FP27)
Port D is a 7-bit output-only port that shares its bits with the LCD backplane/frontplane drivers. Port D lines
are configured as LCD outputs during power-on or reset. PD1–PD3 and PD4–PD7 outputs may be
configured as open-drain outputs by a software option.
Freescale Semiconductor
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. The RESET pin contains an internal Schmitt trigger to improve its noise immunity as an input. An
Bits PC0–PC2 are shared with the SSPI subsystem and may be configured as open-drain outputs.
Bit 3 is shared with the TCAP pin of timer 1 and may be configured as an open-drain output.
Bit 4 is shared with the EVI bit of timer 2 and may be configured as an open-drain output.
Bit 5 is shared with the EVO bit of timer 2 and may be configured as an open-drain output.
Bit 6 is shared with the IRQ2 input. This bit is an open-drain output-only pin configured as an
output.
Bit 7 is shared with the IRQ1 input. This bit is an open-drain output-only pin configured as an
output.
MC68HC05L16 • MC68HC705L16 Data Sheet, Rev. 4.1
Figure
1-4(b). This configuration is possible regardless of how
Functional Pin Description
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