AN1794 datasheet(27/34 Pages) STMICROELECTRONICS

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AN1794

EVAL6208PD board configuration

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EVAL6208PD board configuration

The schematic of the EVAL6208PD board is shown in Figure 8. To use the EVAL6208PD

board with practiSPIN system, the following configuration settings must be made on the

EVAL6208PD:

Component updates: depending on the revision of the board, some or all of the

following changes may be required (or desirable):

To assure safe overcurrent operation:

–

Change C12 to 5.6 nF

–

Change R21 to 100 k

Ω

To assure an adequate 5 V supply, R1 may need to be changed. The minimum

value for R1 is (Vs-5)/(0.03+I)

Ω . Where: Vs is the supply voltage and I is any

additional load placed on the 5 V supply (in amps).

JP1: place JP1 in the INT position to enable the on-board 5 Vdc supply.

Switches: place all four of the switches in the right (toward the L6208) position.

R8 and R17: adjust multi-turn trim pots R8 and R17 fully clockwise.

Note:

A slight click can be heard from the pot when it reaches its end of travel.

R10 and R11: adjust multi-turn trim pots R10 and R11 to the middle of their range.

These pots set the off time of the cycle by cycle current controller and can be fine tuned

while observing the motor current on an oscilloscope or by simply adjusting to raise the

frequency of the audible switching noise to an inaudible level if required.

Motor connections: connect the motor coils at CN3 and CN4. When driving a stepper

motor, one winding is connected to CN3 and the second winding is connected to CN4.

For operation with 2 DC motors one motor is connected to each connector.

Power supply: connect, but do not energize, a 12 to 48 Vdc power supply at CN1

(positive to Vin and negative to GND).

Using a 34 pin ribbon cable connect the EVAL6208PD board to the control interface

board. The two boards should be placed on the bench so that their 34 pin headers are

side by side with the ribbon cable going straight across. Set the following on the ST7

interface board.

WJ1: install WJ1 on the ST7 based control interface board. This allows 5 Vdc power to

be obtained from the target board.

10. JP1 and JP2 and R18: install the JP1 and JP2 jumpers to short the center and left pins

together as shown in Figure 2. This is critical as excessive motor current can result

from misplacement of these jumpers! Set potentiometer R18 to about 50%.

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