COP888CG datasheet(15/53 Pages) NSC

15 / 53 page

Typical Performance Characteristics (−55˚C ≤ T

A = +125˚C) (Continued)

Pin Descriptions

CC and GND are the power supply pins. All VCC and GND

pins must be connected.

CKI is the clock input. This can come from an R/C generated

oscillator, or a crystal oscillator (in conjunction with CKO).

See Oscillator Description section.

RESET is the master reset input. See Reset Description sec-

tion.

The device contains three bidirectional 8-bit I/O ports (C, G

and L), where each individual bit may be independently con-

figured as an input (Schmitt Trigger inputs on ports L and G),

output or TRI-STATE under program control. Three data

memory address locations are allocated for each of these

I/O ports. Each I/O port has two associated 8-bit memory

mapped registers, the CONFIGURATION register and the

output DATA register. A memory mapped address is also re-

served for the input pins of each I/O port. (See the memory

map for the various addresses associated with the I/O ports.)

Figure 4 shows the I/O port configurations. The DATA and

CONFIGURATION registers allow for each port bit to be in-

dividually configured under software control as shown below:

CONFIGURATION

DATA

Port Set-Up

Hi-Z Input

(TRI-STATE Output)

Input with Weak Pull-Up

Push-Pull Zero Output

Push-Pull One Output

PORT L is an 8-bit I/O port. All L-pins have Schmitt triggers

on the inputs.

The Port L supports Multi-Input Wake Up on all eight pins. L1

is used for the USART external clock. L2 and L3 are used for

the USART transmit and receive. L4 and L5 are used for the

timer input functions T2A and T2B. L6 and L7 are used for

the timer input functions T3A and T3B (execpt on the CS se-

ries).

The Port L has the following alternate features:

MIWU or T3B

MIWU or T3A

MIWU or T2B

MIWU or T2A

MIWU or RDX

MIWU or TDX

MIWU or CKX

MIWU

Port G is an 8-bit port with 5 I/O pins (G0, G2–G5), an input

pin (G6), and a dedicated output pin (G1). Pins G0 and

G2–G6 all have Schmitt Triggers on their inputs. Pin G1

serves as the dedicated WDOUT WATCHDOG output, while

pin G7 is either input or output depending on the oscillator

mask option selected. With the crystal oscillator option se-

lected, G7 serves as the dedicated output pin for the CKO

clock output. With the single-pin R/C oscillator mask option

selected, G7 serves as a general purpose input pin but is

also used to bring the device out of HALT mode with a low to

high transition on G7. There are two registers associated

with the G Port, a data register and a configuration register.

Therefore, each of the 5 I/O bits (G0, G2–G5) can be indi-

vidually configured under software control.

Since G6 is an input only pin and G7 is the dedicated CKO

clock output pin (crystal clock option) or general purpose in-

put (R/C clock option), the associated bits in the data and

configuration registers for G6 and G7 are used for special

purpose functions as outlined on the next page. Reading the

G6 and G7 data bits will return zeros.

Note that the chip will be placed in the HALT mode by writing

a “1” to bit 7 of the Port G Data Register. Similarly the chip

will be placed in the IDLE mode by writing a “1” to bit 6 of the

Port G Data Register.

Writing a “1” to bit 6 of the Port G Configuration Register en-

ables the MICROWIRE/PLUS to operate with the alternate

DS012829-40

DS012829-41

DS012829-5

FIGURE 4. I/O Port Configurations

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