mc68hc05pl4b Freescale Semiconductor, Inc, mc68hc05pl4b Datasheet - Page 41

• Manufacturer Part Number: mc68hc05pl4b
• Description: Low-cost Single-chip Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

6.1
6.1.1 Single-chip (Normal) Mode
6.1.2 Self-check Mode
MC68HC05PL4
REV 2.0
This section describes the various operating modes of the MC68HC05PL4.
OPERATING MODES
The MC68HC05PL4 has two operating modes: Single-Chip (Normal) Mode and
Self-Check Mode.
At the rising edge of the RESET, the device latches the states of LED/IRQ and
PB0/KBI0 pins and places itself in the speci ed mode . RESET must be held low
for the prede ned po wer-on reset cycles of the internal PH2 clock after POR, or
for a time t
The conditions required to enter each mode are shown in Table 6-1. The mode of
operation is determined by the voltages on the LED/IRQ and PB0/KBI0 pins on
the rising edge of the external RESET pin.
The Single-Chip Mode is the normal operating mode, and it allows the device to
function as a self-contained microcontroller, with maximum use of the pins for on-
chip peripheral functions.
In the Single-Chip Mode all address and data activity occurs within the MCU and
is not available externally. Single-Chip Mode is entered if the LED/IRQ pin is within
the normal operating voltage range when the rising edge of a RESET occurs. In
Single-Chip Mode, all I/O port pins are available.
The self-check program is mask at location $1E00 to $1FEF, and is used for
checking device functionality under minimum hardware support.
V
RESET Pin
TST
= 2 x V
RL
Table 6-1. Operation Mode Condition After Reset
for any other reset.
DD
Freescale Semiconductor, Inc.
For More Information On This Product,
V
LED/IRQ
SS
V
OPERATING MODES
to V
TST
Go to: www.freescale.com
DD
OPERATING MODES
SECTION 6
April 30, 1998
PB0/KBI0
V
SS
V
to V
DD
DD
GENERAL RELEASE SPECIFICATION
Single-Chip (Normal)
Self-Check
MODE
6-1