Diglient Pmod RS232 Serial Converter and Interface Standard

Features and Specifications

• Maxim Integrated MAX3232 RS232 transceiver
• Standard RS232 DB9 connector
• Optional RTS and CTS handshaking functions
• 1.0 in × 1.3 in (2.5 cm × 3.3 cm) PCB size
• 6-pin Pmod connector with UART interface
• 3.3V Logic Level
• Follows Digilent Pmod Interface Specification Type 3 (UART)

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 Pmod RS232 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.

There are two jumper blocks on the Pmod RS232; JP1 and JP2. These jumper blocks allow the Pmod RS232 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.

*Note: There are two UART signal pin assignment conventions in use on Digilent products. This product uses the old signal assignment convention. Connecting a product using the old convention with one using the new convention requires the use of a UART Crossover Cable (not included). Click here for a more detailed explanation.

Pmod Series Overview

The Digilent Pmod (peripheral module) Series is a small, low-cost peripheral module that can be used with a wide range of embedded systems and development boards. It is designed to extend the capabilities of embedded systems and development boards by adding new features and functionality. The Pmod communicates with host boards using 6, 8 or 12-pin connectors that can carry multiple digital control signals, taking advantage of standard serial protocols such as SPI and I²C. This allows for more effective designs by routing analog signals and power supplies only where they are needed and away from digital controller boards.

What's in the Box

• Pmod RS232
• Custom antistatic Pmod packaging