68HC705H12 Datasheet, PDF (170/196 Pages) Motorola, Inc – General Release Specification

EPROM
15.3.1 Bootloader Functions
Two pins are used to select various bootloader functions. These pins are
PB2 and PB3. Two other pins, PB7 and PB6 are used to drive the PROG
LED and the VERF LED respectively. The programming modes are
shown in Table 15-1.
Table 15-1. Bootloader Functions
PB2
0
0
1
1
PB3
0
1
0
1
MODE
Program/Verify EPROM
Verify only
Jump to RAM
Load RAM and Execute
The bootloader uses an external 14 bit counter to address the memory
device containing the code to be copied. This counter requires a clock
(provided at PB5) and a reset signal (provided at PB4).
NOTE: The EPROM must be erased before performing a program cycle.
For the communication with a host computer via a standard RS-232
interface PB1 is used as transmitter (TX) and PB0 is used as receiver
(RX).
General Release Specification
168
EPROM
MC68HC(7)05H12 — Rev. 1.0
MOTOROLA