7
Hardware user interface
The
board provides a hardware user interface which consists of:
•
a trimmer (TR1) to set the target speed
•
SW1 switch to set motor spin direction
•
SW2 switch to turn the board power supply on or off, thus reducing static consumption to 0 A via Q8 P-
channel MOSFET. If a continuous power supply is needed, for example, to load the firmware onto the MCU,
short J3 connector pins.
All above mentioned interfaces can be replaced by external inputs.
7.1
Detachable interface
If the on-board hardware user interface (SW1, SW2 and TR1) are not used, it is possible to detach the interface
section by breaking the PCB along the slot holes.
You can still program or debug
by connecting an external
to J11 SWD connector.
Figure 6.
STEVAL-PTOOL2V1 detachable section
7.2
Turn on/off circuitry
The board offers the possibility of connecting or disconnecting the battery to the circuitry via an external switch
(J3), to reduce the quiescent consumption to a very low level.
As soon as the switch is closed, the motor can be driven as required by the control algorithm.
By closing the trigger switch, the Q8 PMOS gate is forced low, connecting the battery to the control circuitry.
UM2772
Hardware user interface
UM2772
-
Rev 1
page 14/28