TPMC861 4 Channel Isolated Serial Interface RS422/RS485

4 Channel Isolated Serial Interface RS422/RS485






The TPMC861 is a standard single-width 32 bit PMC module with four channels of high performance RS422/485-HD/FD asynchronous serial interface. Each of the four channels is isolated from the system and against each other by optocoupler and on board DC/DC converter per channel.

The serial channels are accessible through a DB25 connector mounted in the front panel and via P14 I/O. Each channel has a 128byte transmit FIFO and a 128byte receive FIFO to significantly reduce the overhead required to provide data to and get data from the transmitter and receivers. The FIFO trigger levels are programmable. For RS422 and RS485-FD a four wire interface (RX+, RX-, TX+, TX-) plus isolated ground (GND) per channel is supported. For RS485-HD a two wire interface (DX+, DX-) plus isolated ground (GND) per channel is supported. The baud rate is individually programmable up to 460.8Kbaud for each channel. The interrupts are supported.

All channels generate interrupts on PCI interrupt INTA. For fast interrupt source detection the TPMC861 provides a special interrupt status register. Each receiver input and transmitter output of all channels is protected against electrostatic discharge (ESD) up to +/- 15kV according to IEC 1000-4-2.

Technical Specification:


Mechanical Interface

PCI Mezzanine Card (PMC) Interface, Single Size


Electrical Interface

PCI Rev. 2.1 compliant, 33MHz, 32bit PCI, 3.3V and 5V Signaling Voltage


PCI Target Chip

PCI9030 (PLX Technology)


UART Controller

XR16C864 (4 channel UART, RS422/485)


Number of UART Channels



Interface Type

Asynchronous serial interface



128byte transmit FIFO, 128byte receive FIFO per channel



PCI INTA for all channels, on board interrupt status register


I/O Signals / Channel

TX+, TX-, RX+, RX-, isolated GND


Maximum Transfer Rate

Each channel programmable up to 460.8 kbaud



+/-15kV Human Body Model, +/-6kV IEC1000-4-2 Model


I/O Interface

DB25 female connector, 64 pins Mezzanine P14 I/O connector


Power Requirements

33mA typical @ +3.3V
246mA typical @ +5V


Temperature Range

Operating: -40°C to +85°C
Storage: -55°C to +125°C



85 g



5-95 % non-condensing