MC68HC05B6_13 Datasheet, PDF (189/302 Pages) Freescale Semiconductor, Inc – Microcontrollers

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MC68HC705B16
To ensure correct operation of the MC68HC705B16 after power-on, the device must
be reset a second time after power-on. This can be done in software using the
MC68HC705B16 watchdog.
The following software sub-routine should be used:
RESET2 BSET
0, $0C
STOP
Start watchdog
STOP causes immediate watchdog
system reset
The interrupt vector at $3FF0 and $3FF1 must be initialised with the RESET2
address value.
The MC68HC705B16 is a device similar to the MC68HC05B6, but with increased RAM and
15 kbytes of EPROM instead of 6 kbytes of ROM. In addition, the self-check routines available in
the MC68HC05B6 are replaced by bootstrap firmware. The MC68HC705B16 is an OTPROM
(one-time programmable ROM) version of the MC68HC05B16, meaning that once the application
program has been loaded in the EPROM it can never be erased. The entire MC68HC05B6 data
sheet applies to the MC68HC705B16, with the exceptions outlined in this appendix.
MC68HC05B6
Rev. 4.1
MC68HC705B16
14
Freescale
E-1