Information

Digilent Pmod™ Interface Specification
www.digilentinc.com page 9 of 11
Copyright Digilent, Inc. All rights reserved. Other product and company names mentioned may be trademarks of their respective owners.
Pin Signal Direction
1 CTS In
2 TXD Out
3 RXD In
4 RTS Out
5 GND
6 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
Pmod Interface Type 4A (expanded UART)
This provides a UART interface with optional hardware flow control plus additional control signals.
The hardware flow control signals are optional, and some Pmods do not use them. In this case
pins 1 & 4 are not used.
The hardware flow control signal names are defined from the system board perspective. The RTS
signal is an output indicating that the device (host or peripheral) is ready to receive data. The
device asserts this signal low when it is ready to receive data. The CTS signal is an input to the
device (host or peripheral). The device will only transmit data when the CTS input is asserted low.
A peripheral module that uses hardware flow control will connect the host’s RTS signal to its
internal CTS input and the host’s CTS signal to its internal RTS output.
Pin Signal Direction
1 CTS In
2 TXD Out
3 RXD In
4 RTS Out
5 GND
6 VCC
7 INT In
8 RESET Out
9 N/S N/S
10 N/S N/S
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