COP8FG datasheet(11/59 Pages) NSC

11 / 59 page

4.0 Pin Descriptions

The COP8FGx I/O structure enables designers to reconfig-

ure the microcontroller’s I/O functions with a single instruc-

tion. Each individual I/O pin can be independently configured

as output pin low, output high, input with high impedance or

input with weak pull-up device. A typical example is the use

of I/O pins as the keyboard matrix input lines. The input lines

can be programmed with internal weak pull-ups so that the

input lines read logic high when the keys are all open. With

a key closure, the corresponding input line will read a logic

zero since the weak pull-up can easily be overdriven. When

the key is released, the internal weak pull-up will pull the in-

put line back to logic high. This eliminates the need for exter-

nal pull-up resistors. The high current options are available

for driving LEDs, motors and speakers. This flexibility helps

to ensure a cleaner design, with less external components

and lower costs. Below is the general description of all avail-

able pins.

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 the Internal R/C

oscillator, external, or a crystal oscillator (in conjunction with

CKO). See Oscillator Description section.

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

tion.

Each device contains four bidirectional 8-bit I/O ports (C, G,

L and F), where each individual bit may be independently

configured 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 5 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.

Port L supports the Multi-Input Wake Up feature on all eight

pins. Port L has the following alternate pin functions:

L7 Multi-input Wakeup or T3B (Timer T3B Input)

L6 Multi-input Wakeup or T3A (Timer T3A Input)

L5 Multi-input Wakeup or T2B (Timer T2B Input)

L4 Multi-input Wakeup or T2A (Timer T2A Input)

L3 Multi-input Wakeup and/or RDX (USART Receive)

L2 Multi-input Wakeup or TDX (USART Transmit)

L1 Multi-input Wakeup and/or CKX (USART Clock)

L0 Multi-input Wakeup

Port G is an 8-bit port. Pin G0, G2–G5 are bi-directional I/O

ports. Pin G6 is always a general purpose Hi-Z input. All pins

have Schmitt Triggers on their inputs.Pin G1 serves as the

dedicated WATCHDOG output with weak pullup if

WATCHDOG feature is selected by the Mask Option reg-

ister. The pin is a general purpose I/O if WATCHDOG fea-

ture is not selected. If WATCHDOG feature is selected, bit

1 of the Port G configuration and data register does not have

any effect on Pin G1 setup. Pin G7 is either input or output

depending on the oscillator option selected. With the crystal

oscillator option selected, G7 serves as the dedicated output

pin for the CKO clock output. With the internal R/C or the ex-

ternal oscillator option selected, G7 serves as a general pur-

pose Hi-Z input pin and is also used to bring the device out

of HALT mode with a low to high transition on G7.

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 or external clock option), the associated bits in the

data and configuration registers for G6 and G7 are used for

special purpose functions as outlined below. Reading the G6

and G7 data bits will return zeroes.

Each device will be placed in the HALT mode by writing a “1”

to bit 7 of the Port G Data Register. Similarly the device 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

phase of the SK clock. The G7 configuration bit, if set high,

enables the clock start up delay after HALT when the R/C

clock configuration is used.

Config. Reg.

Data Reg.

CLKDLY

HALT

Alternate SK

IDLE

Port G has the following alternate features:

G7 CKO Oscillator dedicated output or general purpose in-

put

G6 SI (MICROWIRE Serial Data Input)

G5 SK (MICROWIRE Serial Clock)

G4 SO (MICROWIRE Serial Data Output)

G3 T1A (Timer T1 I/O)

G2 T1B (Timer T1 Capture Input)

G1 WDOUT WATCHDOG and/or CLock Monitor if WATCH-

DOG enabled, otherwise it is a general purpose I/O

G0 INTR (External Interrupt Input)

Port C is an 8-bit I/O port. The 40-pin device does not have

a full complement of Port C pins. The unavailable pins are

not terminated. A read operation on these unterminated pins

will return unpredictable values. The 28 pin device do not of-

fer Port C. On this device, the associated Port C Data and

Configuration registers should not be used.

Port F is an 8-bit I/O port. The 28--pin device does not have

a full complement of Port F pins. The unavailable pins are

not terminated. A read operation on these unterminated pins

will return unpredictable values.

Port F1–F3 are used for Comparator 1. Port F4–F6 are used

for Comparator 2.

The Port F has the following alternate features:

F6 COMP2OUT (Comparator 2 Output)

F5 COMP2+IN (Comparator 2 Positive Input)

F4 COMP2-IN (Comparator 2 Negative Input)

F3 COMP1OUT (Comparator 1 Output)

F2 COMP1+IN (Comparator 1 Positive Input)

F1 COMP1-IN (Comparator 1 Negative Input)

Note: For compatibility with existing software written for COP888xG devices

and with existing Mask ROM devices, a read of the Port I input pins

COP8FG Datasheet(PDF) 11 Page - National Semiconductor (TI)

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