mc68hc912bc32 Freescale Semiconductor, Inc, mc68hc912bc32 Datasheet - Page 34

• Manufacturer Part Number: mc68hc912bc32
• Description: M68hc12 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

General Description
1.6.4.4 Port DLC
The MC68HC912B32 and MC68HC12BE32 contain the port DLC.
Byte data link communications (BDLC) pins can be configured as general-purpose I/O port DLC. When
BDLC functions are not enabled, the port has seven general-purpose I/O pins, PDLC6–PDLC0. The port
DLC control register (DLCSCR) controls port DLC function. The BDLC function, enabled with the
BDLCEN bit, takes precedence over other port functions.
The port DLC data direction register (DDRDLC) determines whether each port DLC pin is an input or
output. Setting a bit in DDRDLC makes the corresponding pin in port DLC an output; clearing a bit makes
the corresponding pin an input. After reset, port DLC pins are configured as inputs.
When the PUPDLC bit in the DLCSCR register is set, all port DLC input pins are pulled up internally by
an active pullup device.
Setting the RDPDLC bit in register DLCSCR causes all port DLC outputs to have reduced drive level.
Levels are at normal drive capability after reset. RDPDLC can be written anytime after reset. Refer to
Chapter 15 Byte Data Link Communications
(BDLC).
1.6.4.5 Port CAN
The MC68HC(9)12BC32 contains the port CAN.
The port CAN has five general-purpose I/O pins, PCAN[6:2]. The msCAN12 receive pin, RxCAN, and
transmit pin, TxCAN, cannot be configured as general-purpose I/O on port CAN.
The msCAN data direction register (DDRCAN) determines whether each port CAN pin PCAN[6:2] is an
input or output. Setting a bit in DDRCAN makes the corresponding pin in port CAN an output; clearing a
bit makes the corresponding pin an input. After reset, port CAN pins PCAN[6:2] are configured as inputs.
When a read to the port CAN is performed, the value read from the most significant bit (MSB) depends
on the MSB, PCAN7, of the port CAN data register, PORTCAN, and the MSB of DDRCAN: it is 0 if
DDRCAN7 = 0 and is PCAN7 if DDRCAN7 = 1.
When the PEUCAN bit in the port CAN control register (PCTLCAN) is set, port CAN input pins PCAN[6:2]
are pulled up internally by an active pullup device.
Setting the RDRCAN bit in register PCTLCAN causes the port CAN outputs PCAN[6:2} to have reduced
drive level. Levels are at normal drive capability after reset. RDRCAN can be written anytime after reset.
Refer to
Chapter 16 msCAN12
Controller.
1.6.4.6 Port AD
Port AD provides input to the analog-to-digital subsystem and general-purpose input. When
analog-to-digital functions are not enabled, the port has eight general-purpose input pins, PAD7–PAD0.
The ADPU bit in the ATD control register 2 (ATDCTL2) enables the A/D function.
Port AD pins are inputs; no data direction register is associated with this port. The port has no resistive
input loads and no reduced drive controls. Refer to
Chapter 17 Analog-to-Digital Converter
(ATD).
M68HC12B Family Data Sheet, Rev. 9.1
34
Freescale Semiconductor