The Sy422PCI-RT44 is an RS-422 interface module with 4 Duplex channels for use with the general purpose PCI interface cards SyPCI-M2 and SyPCI-M4. When the module is installed onto one of these cards, the combined unit provides the following features:

    Four Phillips industry standard full duplex UART channels

    Flow control using programmable Xon/Xoff characters

    Flow control using CTSN RTSN hardware handshaking (optional)

    Automatic address detection in multi-drop mode

    Three byte general purpose character recognition

    Programmable interrupt priorities

    Automatic identification of highest priority interrupt pending

    Global interrupt and control registers ease set-up and interrupt handling

    Vectored interrupts with programmable interrupt vector formats

·         Interrupt vector modified with channel number

·         Interrupt vector modified with channel number and  channel type

·         Interrupt vector not modified

    Watch dog timer for each receiver

    Programmable Data Formats

·         5 to 8 data bits plus parity

·         odd, even or no parity

·         1, 1.5 or 2 stop bits

    Flexible baud rate selection for receivers and transmitters:

·         22 fixed rates; 50 to 230.4K baud or 100 to 460.8K baud

·         Additional non-standard rates to 500K baud with internal generators

·         Two reload-counters provide additional programmable baud rate generation

·         Simplified baud rate selection

    MHz 1x and 16x data rates full duplex all channels

    Parity, framing and overrun error detection

    False start bit detection

    Line break detection and generation

    Programmable channel mode

·         Normal (full duplex)

·         Diagnostic modes

·         automatic echo

·         local loop back

·         remote loop back

    Four I/O ports per UART for modem controls, clocks, RTSN, I/O etc.

·         All I/O ports equipped with “Change of State Detectors”

    Two global inputs and two global outputs for general purpose I/O.

The Sy422PCI-RT44 module is based on the Philips QUART SC28L194 and provides 4 Rx and 4 Tx RS422/485 channels. Each pair of Rx / Tx channels is capable of Full Duplex operation at rates up to 250k bits / s.

The module uses eight of the 1k x 32 bit Cyclic-Data-Buffers provided on the general purpose SYxxxPCI-M2 card. Four of these are configured for reception and four for transmission.

The user has direct access to the QUART internal registers and consequently can configure individual channels for their particular application.

Once the QUART is configured for operation, the user simply transfers transmit data to the corresponding transmit Cyclic Data Buffer. On detection of data in the Cyclic Data Buffer and the module’s readiness to accept data, the system will automatically transfer Cyclic-Buffer data, byte by byte, to the appropriate TX FIFO from where it will be transmitted over the RS422/485 data bus.

In a similar manner, data received by the QUART is automatically transferred to the corresponding Cyclic Data Buffer from where it can be easily accessed by the host processor, via the PCI interface.

The QUART can be configured to generate interrupts in response to various events and these in turn can be directed to trigger PCI interrupts to the Host System.. The interrupts are controlled in a hierarchical manner so that QUART events generate module interrupts on the mother card which generates a local interrupt to the PCI Interface Chip which finally generates a PCI interrupt to the host computer. Consequently, interrupts  are also handled, by the software, in a hierarchical manner. For interrupts to occur they must be enabled at all three levels and, when they do occur, their status checked at each level. At the card level, the interrupt status determines which module(s) generated the interrupt(s) and at the module level the interrupt status determines which QUART event caused the interrupt.

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