PRODUCT PREVIEW

13

AUTOMOTIVE — 87C196LA

T2CLK

I

Timer 2 External Clock

External clock for timer 2. Timer 2 increments (or decrements) on both rising

and falling edges of T2CLK. It is also used in conjunction with T2DIR for

quadrature counting mode.

T2CLK shares a package pin with P1.0 and EPA0.

T2DIR

I

Timer 2 External Direction

External direction (up/down) for timer 2. Timer 2 increments when T2DIR is high

and decrements when it is low. It is also used in conjunction with T2CLK for

quadrature counting mode.

T2DIR shares a package pin with P1.2 and EPA2.

TXD

O

Transmit Serial Data

In serial I/O modes 1, 2, and 3, TXD transmits serial port output data. In mode

0, it is the serial clock output.

TXD shares a package pin with P2.0 and PVER.

V

CC

PWR

Digital Supply Voltage

Connect each V

V

PP

PWR

Programming Voltage

V

50 ns. Use this method to exit powerdown only when using an external clock

source because it enables the internal phase clocks, but not the internal

oscillator.

If you do not plan to use the powerdown feature, connect V

V

REF

PWR

Reference Voltage for the A/D Converter

This pin supplies operating voltage to the A/D converter.

V

1

GND

Digital Circuit Ground

These pins supply ground for the digital circuitry. Connect each V

to ground through the lowest possible impedance path. V

to the core ground region of the microcontroller, while V

to the port ground region. (ANGND is connected to the analog ground region.)

Separating the ground regions provides noise isolation.

WR#

O

This active-low output indicates that an external write is occurring. This signal is

asserted only during external memory writes.

Forcing WR# high while RESET# is low causes the device to enter PLL-bypass

mode. When the device is in PLL-bypass mode, the internal phase clocks

operate at one-half the frequency of the frequency on XTAL1.

WR# shares a package pin with P5.2, WRL#, and PLLEN.

chip configuration register 0 (CCR0) determines whether it functions as WR#

or WRL#. CCR0.2 = 1 selects WR#; CCR0.2 = 0 selects WRL#.

Table 4. Signal Descriptions (Continued)

Name

Type

Description