Motorola M68EVB912B32 Manuel d'utilisateur télécharger pdf (Page 5)

Engineering Bulletin

Hardware Configuration

EB183 — Rev. 1.0

MOTOROLA 5

Hardware Configuration

Setting up the

Debugging

Hardware

Since programming the FLASH EEPROM takes a finite amount of time

and is dependent on a reliable programming voltage from an exterior

source, it is difficult to tell if the procedure worked immediately. To

simplify the debugging of the process, try using a few hardware tricks

that are listed in this bulletin. For debugging hardware, simply use an

light-emitting diode (LED) connected to a port pin on the

MC68HC912B32 device that blinks when an error is encountered, as

well as an LED attached to another port pin which lights when the

process is complete. For use with the code in this bulletin, connect a red

LED to PA0, with a 1-KΩ current limiting resistor to indicate errors. In like

manner, connect a green LED to PA1 to indicate that the process has

completed.

Setting up the

M68HC12B32EVB

Be sure to connect your V

source to W8 on the M68HC12B32EVB

with the proper polarity. The ground should be connected to the pin

closest to the edge of the board and farthest from the microcontroller.

This applies V

to the board, but the jumper on W7 actually transfers

to the V

pin (pin 69) on the microcontroller. When a jumper is

placed on the left two pins of W7 (with board facing so that silk screening

can be read), V

is connected to the chip. When the jumper is moved

to the right, so that the center pin and right pin are shorted, then V

applied to the chip. This is the default location, and a jumper should

always be located here to maintain the voltage on the V

pin on the

MCU at V

when programming and erasing are not occurring.

NOTE:

should be 11.4–11.8 volts for mask sets 1H91F and 3H91F. For all

other masks, use 11.4–12.6 volts (12 volts

5%).

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Motorola M68EVB912B32 Manuel d'utilisateur Page 5

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