MC68HC05SU3A Datasheet, PDF(65/80 Page) Freescale Semiconductor, Inc – Fully static chip design featuring the industry standard 8-bit M68HC05 core

English

English German Russian Spanish Italian Polish Chinese Japanese Korean French Portuguese	Language :

MC68HC05SU3A Datasheet, PDF (65/80 Pages) Freescale Semiconductor, Inc – Fully static chip design featuring the industry standard 8-bit M68HC05 core

◁

Freescale Semiconductor, Inc.

OPERATING MODES

The MC68HC05SU3A has two modes of operation: the User Mode and the Self-Check Mode.

Table 9-1 shows the conditions required for entering the two operating modes.

RESET

VTST = 2 Ã VDD

Table 9-1 Mode Selection

VPP

VSS to VDD

VTST

PB1

VSS to VDD

VDD

MODE

USER

SELF-CHECK

9.1

User Mode

The normal operating mode of the MC68HC05SU3A is the User mode. This mode is entered on

the rising edge of RESET when the VPP and PB1 pins are between VSS and VDD.

9.2

Self-Check Mode

The Self-check mode is provided on the MC68HC05SU3A for the user to check device functions

with an on-chip self-check program masked at location $1F00 to $1FEF under minimum hardware

support. The self-check schematic is shown in Figure 9-1. Self-check mode is entered on the

rising edge of RESET when the VPP pin is at VTST (2ÃVDD) and PB1 pin is at VDD. Once in the

self-check mode, PB1 can then be used for other purposes. After entering the self-check mode,

CPU branches to the self-check program and carries out the self-check. Self-check is a repetitive

test, i.e. if all parts are checked to be good, the CPU will repeat the self-check again. Therefore,

the LEDs attached to Port A will be ï¬ashing if the device is good; else the combination of LEDsâ

on-off pattern can show what part of the device is suspected to be bad. Table 9-2 lists the LEDsâ

on-off patterns and their corresponding indications.

TPG

MC68HC05SU3A

OPERATING MODES

For More Information On This Product,

9-1

Go to: www.freescale.com

▷