XC68HC705F32 Motorola, XC68HC705F32 Datasheet - Page 50

• Manufacturer Part Number: XC68HC705F32
• Description: MICROCONTROLLER
• Manufacturer: Motorola

4
4.6
Port E is an 8-bit bidirectional port which is shared with the timer system, the independent 32 kHz
clock system and the PWM. When the corresponding bit in the port E control register is set to 1,
the pins PE1 and PE3 are connected to TCMP1 and TCMP2 of the timer system, PE4 is
connected to the independent clock system, it becomes REFRESH, and PE5 – PE7 become
PWM1 – PWM3 of the PWM system. Pins PE0 and PE2 are always connected to the timer system
(TCAP1 and TCAP2). These two lines must be set to input by resetting the DDR to enable correct
TCAP function.
Reset does not affect the data register, but it clears the data direction register and the control
register. The default setting of the register control bits is 0, making the pins general purpose I/O
lines. The direction of the pins is then determined by their corresponding bits in DDR (0 – input, 1
– output). Port E has open-drain outputs, it therefore requires external pull-up resistors for each
pin when they are used as outputs.
Note:
4.7
These five ports are shared with the frontplanes FP39 – FP0. The default setting of the port control
bits, during reset, is 0, setting the pins in port F and port G to input only, and the pins in ports H,
I and J, to output only. At power on or reset, the output only port data registers are cleared, so that
these pins are driving logical 0. When the corresponding port control register bit is set to a 1, the
pin is connected to the LCD frontplane driver. All port J outputs are open-drain.
MOTOROLA
4-6
As the voltage at port D or port E is driven above V
to conduct and tend to clamp the input voltage to protect the input buffer. The voltage
at which this condition will occur varies significantly, from lot to lot, and over the
temperature range. At room temperature, the pin typically does not draw any current
until approximately 18V.
Port E
Ports F, G, H, I and J
PARALLEL INPUT/OUTPUT PORTS
DD
, the protection device will begin
MC68HC05F32
TPG