Serial interface pin descriptions – Pololu Simple User Manual
Page 34
Whenever connecting devices, remember to wire the grounds together, and ensure that each device
is properly powered. Unpowered devices with a TTL serial port can turn on or partially on, drawing
power from the serial line, which means that extra care must be taken when turning power off and on
to reset the devices.
Note: You must use an inverter and level shifter such as a MAX232 or a
if you want to interface an RS-232 device with the Simple Motor
Controller. Connecting an RS-232 device directly to the Simple Motor Controller can permanently damage
it.
Serial Interface Pin Descriptions
Pin
Direction
Description
RX
Input
Simple Motor Controller TTL serial receive pin. This should be connected to the
TTL serial output (transmit line) of your other device. This connection is only
required if you want to send serial commands to the motor controller from your other
device.
TX
Output
Simple Motor Controller TTL serial transmit pin. This should be connected to the
TTL serial input (receive line) of your other device. This connection is only required
if you want to receive serial feedback from the motor controller.
RST
Input
Simple Motor Controller active-low reset pin. This pin is internally pulled high;
driving it low resets the motor controller. You must wait for at least 1 ms after a reset
to transmit to the Simple Motor Controller. This pin can be left disconnected in most
applications.
ERR
In/Out
Simple Motor Controller error output. This pin outputs high when there is an error
that is stopping the motor, turning on the red error LED in the process; otherwise, it
is weakly pulled low. This pin is documented in more detail below.
TXIN
Input
Simple Motor Controller chained transmission input pin. Connecting the transmit
output of another serial device to this pin will cause that device’s transmissions to be
output from the Simple Motor Controller’s TX pin. This pin is documented in more
detail below.
GND
Ground connection point. Your serial device must share a common ground with the
Simple Motor Controller.
VIN
Output
Board power access point. This pin is internally connected to the large VIN pad
where motor power is supplied and can be used to power other components in the
system, but it should not be used to supply more than 500 mA. This is not a
regulated, logic-level output.
These pins have a 0.1" spacing.
Simple Wiring Example: Connecting to a Microcontroller
All you need to control the Simple Motor Controller with a microcontroller is a connection between the
microcontroller’s TTL serial transmit pin and the Simple Motor Controller’s RX pin. If you want to get feedback
Pololu Simple Motor Controller User's Guide
© 2001–2014 Pololu Corporation
4. Connecting Your Motor Controller
Page 34 of 101