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8XC196Kx,8XC196Jx,87C196CA microcontroller family user's manual.1995.pdf
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CHAPTER 13 MINIMUM HARDWARE CONSIDERATIONS

The 8XC196Kx, Jx, and CA have several basic requirements for operation within a system. This chapter describes options for providing the basic requirements and discusses other hardware considerations.

13.1 MINIMUM CONNECTIONS

Table 13-1 lists the signals that are required for the device to function and Figure 13-1 shows the connections for a minimum configuration.

 

 

Table 13-1. Minimum Required Signals

Signal

Type

Description

Name

 

 

 

 

 

ANGND

GND

Analog Ground

 

 

ANGND must be connected for A/D converter and port 0 operation. ANGND and

 

 

VSS should be nominally at the same potential.

RESET#

I/O

Reset

 

 

A level-sensitive reset input to and open-drain system reset output from the micro-

 

 

controller. Either a falling edge on RESET# or an internal reset turns on a pull-down

 

 

transistor connected to the RESET# pin for 16 state times. In the powerdown and

 

 

idle modes, asserting RESET# causes the chip to reset and return to normal

 

 

operating mode. The microcontroller resets to 2080H.

 

 

 

VCC

PWR

Digital Supply Voltage

 

 

Connect each VCC pin to the digital supply voltage.

VPP

PWR

Programming Voltage

 

 

During programming, the VPP pin is typically at +12.5 V (VPP voltage). Exceeding the

 

 

maximum VPP voltage specification can damage the device.

 

 

VPP also causes the device to exit powerdown mode when it is driven low for at least

 

 

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.

 

 

On devices with no internal nonvolatile memory, connect VPP to VCC.

 

 

 

VREF

PWR

Reference Voltage for the A/D Converter

 

 

This pin also supplies operating voltage to both the analog portion of the A/D

 

 

converter and the logic used to read port 0.

 

 

 

VSS

GND

Digital Circuit Ground

 

 

Connect each VSS pin to ground through the lowest possible impedance path.

13-1

8XC196Kx, Jx, CA USER’S MANUAL

 

 

Table 13-1. Minimum Required Signals(Continued)

Signal

Type

Description

Name

 

 

 

 

 

XTAL1

I

Input Crystal/Resonator or External Clock Input

 

 

Input to the on-chip oscillator and the internal clock generators. The internal clock

 

 

generators provide the peripheral clocks, CPU clock, and CLKOUT signal. When

 

 

using an external clock source instead of the on-chip oscillator, connect the clock

 

 

input to XTAL1. The external clock signal must meet the VIH specification for XTAL1

 

 

(see datasheet).

 

 

 

XTAL2

O

Inverted Output for the Crystal/Resonator

 

 

Output of the on-chip oscillator inverter. Leave XTAL2 floating when the design uses

 

 

a external clock source instead of the on-chip oscillator.

 

 

 

13.1.1 Unused Inputs

For predictable performance, it is important to tie unused inputs to VCC or VSS. Otherwise, they can float to a mid-voltage level and draw excessive current. Unused interrupt inputs may generate spurious interrupts if left unconnected.

13.1.2 I/O Port Pin Connections

Tie unused input-only port inputs to VSS as shown in Figure 13-1. Chapter 6, “I/O Ports,” contains information about initializing and configuring the ports. Table 13-2 lists the sections, with page numbers, that contain the information for each port.

 

Table 13-2. I/O Port Configuration Guide

Port

Where to Find Configuration Information

 

 

Port 0

“Standard Input-only Port Considerations” on page 6-3

Ports 1 and 2

“Bidirectional Port Pin Configurations” on page 6-10 and “Bidirectional Port Considerations”

 

on page 6-12

 

 

Ports 3 and 4

“Bidirectional Ports 3 and 4 (Address/Data Bus) Operation” on page 6-16

Ports 5 and 6

“Bidirectional Port Pin Configurations” on page 6-10 and “Bidirectional Port Considerations”

 

on page 6-12

13-2

MINIMUM HARDWARE CONSIDERATIONS

VCC

0.01 µF

VCC

1 M

(Note 3)

VCC

+

1 µF

+

1 µF

 

 

 

 

 

(Note 1)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

20 pF

 

 

 

 

20 pF

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

XTAL2

 

XTAL1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

VCC

 

 

 

RESET#

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(Note 2)

 

 

 

 

 

 

 

 

 

 

 

VCC

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

+

 

 

 

VSS

 

 

 

 

 

EA#

 

 

 

 

 

 

 

 

 

 

 

 

 

 

4.7 µF

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

NMI

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

VPP

 

 

BUSWIDTH

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

VCC

 

 

 

 

 

 

 

 

 

 

 

 

 

 

VREF

 

 

 

 

READY

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

ANGND

 

 

 

 

 

BHE#

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

RD#

 

 

 

 

 

 

Port 5 / Bus Control

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

WR#

 

 

 

 

 

 

 

Input-only

 

 

 

 

 

 

 

 

 

 

 

 

 

(Note 4)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

INST

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Port Pins

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(Note 5)

 

 

 

 

 

ALE

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

8XC196 Device

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Notes:

1.See the datasheet for the oscillator frequency range (FOSC) and the crystal manufacturer's datasheet for recommended load capacitors.

2.The number of VCC and VSS pins varies with package type (see datasheet). Be sure to connect each VCC pin to the supply voltage and each VSS pin to ground.

3.Connect the RC network to VPP only if powerdown mode will be used. Otherwise, connect VPP to VCC.

4.No connection is required.

5.Tie all input-only port pins to VSS.

A2643-02

Figure 13-1. Minimum Hardware Connections

13-3

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