DESCRIPTION

The PM7384 FREEDM-84P672 Frame Engine and Datalink Manager device is a monolithic integrated circuit that implements HDLC processing, and PCI Bus memory management functions for a maximum of 672 bi-directional channels.

FEATURES

? Single-chip multi-channel HDLC controller with a 66 MHz, 32 bit Peripheral Component Interconnect (PCI) Revision 2.1 bus for configuration, monitoring and transfer of packet data, with an on-chip DMA controller with scatter/ gather capabilities.

? Supports up to 672 bi-directional HDLC channels assigned to a maximum of 84 channelised or unchannelised links conveyed via a Scaleable Bandwidth Interconnect (SBI) interface.

? Data on the SBI interface is divided into 3 Synchronous Payload Envelopes (SPEs). Each SPE can be configured independently to carry data for either 28 T1/J1 links, 21 E1 links, or 1 unchannelised DS-3 link.

? Links in a SPE can be configured individually to operate in a clear channel mode, in which case all framing bit locations are assumed to be carrying HDLC data.

? Links in an SPE can be configured individually to operate in channelised mode, in which case, the number of time-slots assigned to an HDLC channel is programmable from 1 to 24 (for T1/J1 links) and from 1 to 31 (for E1 links).

? Supports three bi-directional HDLC channels each assigned to an unchannelised link with arbitrary rate link of up to 51.84 MHz when SYSCLK is running at 45 MHz. Each link may be configured individually to replace one of the SPEs conveyed on the SBI interface.

? For each channel, the HDLC receiver supports programmable flag sequence detection, bit de-stuffing and frame check sequence validation. The receiver supports the validation of both CRC-CCITT and CRC-32 frame check sequences.

? For each channel, the receiver checks for packet abort sequences, octet aligned packet length and for minimum and maximum packet length. The receiver supports filtering of packets that are larger than a user specified maximum value.

? Alternatively, for each channel, the receiver supports a transparent mode where each octet is transferred transparently to host memory. For channelised links, the octets are aligned with the receive time-slots.

? For each channel, time-slots are selectable to be in 56 kbits/s format or 64 kbits/s clear channel format.

? For each channel, the HDLC transmitter supports programmable flag sequence generation, bit stuffing and frame check sequence generation. The transmitter supports the generation of both CRC-CCITT and CRC-32 frame check sequences. The transmitter also aborts packets under the direction of the host or automatically when the channel underflows.

? Supports two levels of non-preemptive packet priority on each transmit channel. Low priority packets will not begin transmission until all high priority packets are transmitted.

? Alternatively, for each channel, the transmitter supports a transparent mode where each octet is inserted transparently from host memory. For channelised links, the octets are aligned with the transmit time-slots.

? Provides 32 Kbytes of on-chip memory for partial packet buffering in both the transmit and receive directions. This memory may be configured to support a variety of different channel configurations from a single channel with 32 Kbytes of buffering to 672 channels, each with a minimum of 48 bytes of buffering.

? Supports PCI burst sizes of up to 256 bytes for transfers of packet data.

? Provides a standard 5 signal P1149.1 JTAG test port for boundary scan board test purposes.

? Supports 3.3 Volt PCI signaling environment.

? Supports 3.3 Volt I/O on non-PCI signals.

? Low power 2.5 Volt 0.25 μm CMOS technology.

? 352 pin enhanced ball grid array (SBGA) package.

APPLICATIONS

? IETF PPP interfaces for routers

? Frame Relay interfaces for ATM or Frame Relay switches and multiplexers

? FUNI or Frame Relay service inter-working interfaces for ATM switches and multiplexers.

? Internet/Intranet access equipment.

? Packet-based DSLAM equipment.

? Packet over SONET.

? PPP over SONET.