• Maxim Integrated MAX3232 RS232 transceiver
• Standard RS232 DB9 connector
• Optional RTS and CTS handshaking functions
• Small PCB size for flexible designs 1.0" × 1.3" (2.5 cm × 3.3 cm)
• 6-pin Pmod connector with UART interface

The Digilent Pmod RS232 converts between digital logic voltage levels to RS232 voltage levels using the Maxim Integrated MAX3232 transceiver. The RS232 module is configured as a data communications equipment (DCE) device. It connects to data terminal equipment (DTE) devices, such as the serial port on a PC, using a straight-through cable.

The PmodRS232 communicates with the host board via the UART protocol. The arrangement of the pins is the the old UART communication style so that a crossover cable will be required if attaching this Pmod to one of the dedicated UART Pmod headers on a Digilent system board.

A pinout description table and diagram for the PmodRS232 are provided below:

There are two jumper blocks on the PmodRS232; JP1 and JP2. These jumper blocks allow the PmodRS232 to communicate in either a 3-wire or 5-wire operation. When the jumper block on JP2 is loaded and the block on JP1 is unloaded, the on-board chip has its RTS and CTS lines tied together, indicating to the MAX3232 that it is free to transfer data whenever it receives any and enabling 3-wire communication. JP1 must be unloaded in this configuration to ensure that pins 1 and 2 on the Pmod header are not shorted together which could potentially damage the system board.

5-wire communication requires that pin 1 of JP1 is connected to pin 1 of JP2, and that pin 2 of both JP1 and JP2 are tied together as well, effectively allowing for CTS/RTS handshaking between the Pmod header and the on-board chip. Both the fifth wire in this configuration and the third wire in the 3-wire communication is the ground signal line

Any external power applied to the PmodRS232 must be within 3V and 5.5V; however, it is recommended that Pmod is operated at 3.3V.