Datasheet
Digilent Pmod™ Interface Specification 1.2.0
Copyright Digilent, Inc. All rights reserved.
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Page 9 of 11
Pin #
Signal
Direction
Alternate Signal
Direction
1
CTS
In
GPIO
In/Out
2
TXD
Out
-
-
3
RXD
In
-
-
4
RTS
Out
GPIO
In
5
GND
6
VCC
7
GPIO
In/Out
INT
In
8
GPIO
In/Out
RESET
Out
9
GPIO
In/Out
-
-
10
GPIO
In/Out
-
-
11
GND
12
VCC
CTS - Device will only transmit when this signal is asserted
RTS - Device is ready to receive data
RXD - Data from peripheral to host
TXD - Data from host to peripheral
INT - Interrupt signal from peripheral to host
RESET - Reset signal for host to reset peripheral
5.4 H-Bridge
Pmod Interface Type 4 (H-Bridge)
This interface provides for controlling a single H-Bridge with motor speed sensing feedback. The DIR pin sets the
rotational direction of the motor. The EN signal is pulse width modulated to control the effective voltage applied to
the motor. EN is an active high signal, i.e. a high logic level enables current flow through the bridge. The SA and SB
signals are quadrature encoder feedback signals used to sense the motor speed. These are square wave signals,
whose frequency is proportional to motor rotational speed and that are in quadrature. (i.e. 90 out of phase). Note
pins 3 and 4 can be left unconnected if feedback is not required.
Pin #
Signal
Direction
1
DIR
Out
2
EN
Out
3
SA
In
4
SB
In
5
GND
6
VCC
DIR - Motor direction
EN - Motor enable, active high
SA - feedback sense A
SB - feedback sense B
Pmod Interface Type 5 (Dual H-Bridge)
This interface provides for controlling two independent H-Bridges. This can be used to control two brushed DC
motors, or the two phases of a bi-polar stepper motor. The EN signal is pulse width modulated to control the
effective voltage applied to the motor. EN is an active high signal, i.e. a high logic level enables current flow
through the bridge.