MC68HC05C9A Datasheet, PDF (19/124 Pages) Freescale Semiconductor, Inc – Microcontrollers

Functional Pin Descriptions
PA6
1
PA5
2
PA4
3
PA3
4
PA2
5
PA1
6
PA0
7
PB0
8
PB1
9
PB2
10
PB3
11
33
TCMP
32
PD5/SS
31
PD4/SCK
30
PD3/MOSI
29
PD2/MISO
28
PD1/TDO
27
PD0/RDI
26
PC0
25
PC1
24
PC2
23
PC3
Figure 1-6. 44-Pin QFP Pin Assignments
NOTE
If MC68HC705C9A devices are to be used in the same socket, pin 43
should be tied to V_DD.
1.5.1 V_DD and V_SS
Power is supplied to the MCU using these two pins. V_DD is the positive supply and V_SS is ground.
1.5.2 IRQ
This interrupt pin has an option that provides two different choices of interrupt triggering sensitivity.
The IRQ pin contains an internal Schmitt trigger as part of its input to improve noise immunity. Refer to
Chapter 4 Interrupts for more detail.
1.5.3 OSC1 and OSC2
These pins provide control input for an on-chip clock oscillator circuit. A crystal or ceramic resonator
connected to these pins provides a system clock. The internal frequency is one-half the crystal frequency.
1.5.4 RESET
As an input pin, this active low RESET pin is used to reset the MCU to a known startup state by pulling
RESET low. As an output pin, the RESET pin indicates that an internal MCU reset has occurred. The
MC68HC05C9A Advance Information Data Sheet, Rev. 5.1
Freescale Semiconductor
19