MC68HC705SR3 MOTOROLA [Motorola, Inc], MC68HC705SR3 Datasheet - Page 88

• Manufacturer Part Number: MC68HC705SR3
• Description: High-density Complementary Metal Oxide Semiconductor (HCMOS) Microcontroller Units
• Manufacturer: MOTOROLA [Motorola, Inc]

A
A.2
The MC68HC705SR3 has two modes of operation – user mode and EPROM bootstrap mode.
Table A-1 shows the conditions required to enter each mode on the rising edge of RESET.
A.3
The normal operating mode of the MC68HC705SR3 is the user mode. User mode will be entered
on the rising edge of RESET when the V
Warning: In the MC68HC705SR3, all vectors are fetched from EPROM in user mode; therefore,
A.4
The bootstrap mode is provided as a mean of self-programming MC68HC705SR3 EPROM with
minimal circuitry, and can only run in the crystal oscillator mode. Bootstrap mode will be entered
on the rising edge of RESET when the V
the bootstrap mode, PB1 can then be used for other purposes. After entering the bootstrap mode,
CPU branches to the bootstrap program and carries out the EPROM programming routine. The
user EPROM consists of 3840 bytes, from location $1000 to $1EFF.
This program handles copying of user code from an external EPROM into the on-chip EPROM.
The bootstrap function does not have to be done from an external EPROM, but it may be done
from a host.
The user code must be a one-to-one correspondence with the internal EPROM addresses.
MOTOROLA
A-2
the EPROM must be programmed (via the bootstrap mode) before the device is
powered up in user mode.
V
TST
Modes of Operation
User Mode
Bootstrap Mode
RESET
=2 V
Table A-1 MC68HC705SR3 Operating Mode Entry Conditions
5V
Freescale Semiconductor, Inc.
DD
For More Information On This Product,
V
SS
V
V
to V
TST
PP
Go to: www.freescale.com
DD
MC68HC705SR3
PP
PP
pin is at V
and PB1 pins are between V
V
SS
PB1
V
to V
DD
TST
DD
(2 V
DD
) and PB1 pin is at V
BOOTSTRAP
MODE
USER
SS
and V
MC68HC05SR3
DD
.
DD
. Once in
TPG