OPERATING INSTRUCTIONS
M68HC11EVBU/D
4-3
4.4
OPERATING PROCEDURES
The EVBU is a simplified debugging/evaluating tool designed for debugging user programs and
evaluation of MC68HC11 family devices. Use jumper header J2 to determine weather the
BUFFALO monitor prompt is displayed, or if a jump to internal EEPROM is executed. Refer to
paragraph 2.3.1 for additional program execution selection information.
At reset, the monitor detects the state of the PE0 line. If a low state is detected, the monitor
program is executed and the prompt displayed. If a high state is detected, the monitor
automatically jumps directly to EEPROM (address location $B600) and executes user program
code without displaying the monitor prompt.
4.4.1
Debugging/Evaluation
The debugging/evaluation operation lets you debug user code under control of the BUFFALO
monitor program. User code can be assembled in one of two methods. The first method
assembles code using the BUFFALO monitor one-line assembler.
The second method, you assemble code on a host computer and then download it to the EVBU
user RAM or EEPROM in Motorola S-record format. The monitor program is then used to debug
the assembled user code.
A download to EEPROM will work if the baud rate is slow enough to allow EEPROM
programming. Since erasure and programming both require 10 milliseconds, a slow baud rate
(300 baud) will have to be used to ensure enough time between characters. If the EEPROM is
bulk erased prior to downloading, 600 baud allows enough time between characters.
4.4.2
Alternate Baud Rates
The following text assumes that a personal computer (PC) is used as the terminal device, and a
user program is assembled on the PC to produce an S-record object file which is to be
downloaded into EVBU EEPROM. For this example, no assumptions are made about the
previous EEPROM contents. During the download operation, BUFFALO determines (on a byte-
by-byte basis) whether or not erasure is required prior to programming a downloaded value into
each EEPROM location. Since erasure and programming both require 10 milliseconds, a slow
baud rate (300 baud) will have to be used to ensure enough time between characters.
Summary of Contents for M68HC11EVBD
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