Texas Instruments VLYNQ Port manual Users Guide, Introduction, Purpose of the Peripheral, Features

User's Guide

SPRUE36A – September 2007

VLYNQ Port

1 Introduction

1.1Purpose of the Peripheral

The VLYNQ™ communications interface port is a low pin count, high-speed, point-to-point serial interface in the TMS320DM644x Digital Media System-on-Chip (DMSoC) used for connecting to host processors and other VLYNQ-compatible devices. The VLYNQ port is a full-duplex serial bus where transmit and receive operations occur separately and simultaneously without interference.

VLYNQ enables the extension of an internal bus segment to one or more external physical devices. The external devices are mapped to local physical address space and appear as if they are on the internal bus of the DM644x DMSoC. The external devices must also have a VLYNQ interface.

VLYNQ uses a simple block code (8b/10b) packet format and supports in-band flow control so that no extra terminals are needed to indicate that overflow conditions might occur.

The VLYNQ module on the DM644x DMSoC serializes a write transaction to the remote/external device and transfers the write via the VLYNQ port (TX pins). The remote VLYNQ module deserializes the transaction on the other side.

The read transactions to the remote/external device follow the same process, but the remote device's VLYNQ module serializes the read return data and transfers it to the VLYNQ port (RX pins). The read return data is finally deserialized and released to the device internal bus.

The external device can also initiate read and write transactions.

1.2Features

The general features of the VLYNQ port are:

∙Low pin count (10 pin interface, scalable to as low as 3 pins)

∙No tri-state signals

–All signals are dedicated and driven by only one device

–Necessary to allow support for high-speed PHYs

∙Scalable Performance

–Programmable frequency and 1 to 4 bits for TX and RX data

–Performance increases linearly as the data port width increases

∙Simple packet-based transfer protocol for memory-mapped access

–Write request/data packet

–Read request packet

–Read response data packet

–Interrupt request packet

∙Auto width negotiation

SPRUE36A –September 2007 VLYNQ Port 9

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