MC68HC908JB8 Datasheet, PDF (214/286 Pages) Motorola, Inc – MICROCONTROLLERS

Input/Output Ports (I/O)
PTE4 pin functions as an external interrupt when PTE4IE=1 in the
IRQ option control register (IOCR) and USBEN=0 in the USB address
register (USB disabled). (See 13.9 IRQ Option Control Register.)
D– and D+ — USB Data Pins
D– and D+ are the differential data lines used by the USB module.
(See Section 9. Universal Serial Bus Module (USB).)
The USB module enable bit, USBEN, in the USB address register
(UADDR) controls the pin options for PTE4/D– and PTE3/D+. When
the USB module is enabled, PTE4/D– and PTE3/D+ function as USB
data pins D– and D+. When the USB module is disabled, PTE4/D–
and PTE3/D+ function as 10mA open-drain pins for PS/2 clock and
data use.
The Pullup enable bit, PULLEN, in the USB control register 3 (UCR3)
enables a 1.5kΩ pullup on D– pin when the USB module is enabled.
(See 9.8.8 USB Control Register 3.)
NOTE:
PTE4/D– pin has two programmable pullup resistors. One is used for
PTE4 when the USB module is disabled and another is used for D–
when the USB module is enabled.
TCH1–TCH0 — Timer Channel I/O Bits
The PTE2/TCH1–PTE1/TCH0 pins are the TIM input capture/output
compare pins. The edge/level select bits, ELSxB and ELSxA,
determine whether the PTE2/TCH1–PTE1/TCH0 pins are timer
channel I/O pins or general-purpose I/O pins. (See Section 11. Timer
Interface Module (TIM).)
TCLK — Timer Clock Input
The PTE0/TCLK pin is the external clock input for the TIM. The
prescaler select bits, PS[2:0], select PTE0/TCLK as the TIM clock
input. When not selected as the TIM clock, PTE0/TCLK is available
for general purpose I/O. (See Section 11. Timer Interface Module
(TIM).)
NOTE:
Data direction register E (DDRE) does not affect the data direction of
port E pins that are being used by the TIM. However, the DDRE bits
always determine whether reading port E returns the states of the
latches or the states of the pins.
Technical Data
214
MC68HC908JB8•MC68HC08JB8•MC68HC08JT8 — Rev. 2.3
Input/Output Ports (I/O)
Freescale Semiconductor