General Description
M68HC12B Family Data Sheet, Rev. 9.1
24
Freescale Semiconductor
1.5 Ordering Information
The M68HC12B-series devices are available in 80-pin quad flat pack (QFP) packaging and are shipped
in 2-piece sample packs, 84-piece trays, or 420-piece bricks.
Operating temperature range, package type, and voltage requirements are specified when ordering the
specific device.
Documents to assist in product selection are available from the Freescale Literature Distribution Center
or your local Freescale sales offices.
Product selection guides can also be found on the worldwide web at this URL:
http://freescale.com
Evaluation boards, assemblers, compilers, and debuggers are available from Freescale and from
third-party suppliers. An up-to-date list of products that support the M68HC12 Family of microcontrollers
can be found on the worldwide web at this URL:
http://freescale.com
1.6 Pinout and Signal Descriptions
1.6.1 Pin Assignments
The MCU is available in an 80-pin quad flat pack (QFP).
Figure 1-3
and
Figure 1-4
show the pin
assignments. Most pins perform two or more functions, as described in the
1.6.3 Signal Descriptions
.
1.6.2 Power Supply Pins
The MCU power and ground pins are described here and summarized in
Table 1-2
.
1.6.2.1 V
DD
and V
SS
V
DD
and V
SS
are the internal power supply and ground pins. Because fast signal transitions place high,
short-duration current demands on the power supply, use bypass capacitors with high-frequency
characteristics and place them as close to the MCU as possible. Bypass requirements depend on how
heavily the MCU pins are loaded.
1.6.2.2 V
DDX
and V
SSX
V
DDX
and V
SSX
are the external power supply and ground pins. Because fast signal transitions place high,
short-duration current demands on the power supply, use bypass capacitors with high-frequency
characteristics and place them as close to the MCU as possible. Bypass requirements depend on how
heavily the MCU pins are loaded.
1.6.2.3 V
DDA
and V
SSA
V
DDA
and V
SSA
are the power supply and ground pins for the analog-to-digital converter (ATD). This
allows the supply voltage to be bypassed independently.
1.6.2.4 V
RH
and V
RL
V
RH
and V
RL
are the reference voltage pins for the ATD.