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Overview
The Lattice Common Public Radio Interface (CPRI) IP core together with SERDES and Physical Coding Sublayer (PCS) functionality integrated in the LatticeECP3, LatticeECP2M, LatticeSC/M FPGAs implements the physical layer of the CPRI specification and interleaves IQ data with synchronization, control and management information. It can be used to connect Radio Equipment Control (REC) and Radio Equipment (RE) modules.
Features
- Supports the physical link layer (Layer 1) of the CPRI specification
- Supports three standard bit rates of the CPRI specification
- 614.4 Mbps
- 1228.8 Mbps
- 2457.6 Mbps
- 3072 Mbps
- Supports 8b/10b encoding/decoding performed in the PCS/SERDES
- Supports code-violation detection performed in the PCS/SERDES
- Performs CPRI Hyperframe Framing
- Performs interleaving of IQ data, sync, C&M data, and vendor specific information
- Provides an 8-, 16-, or 32-bit parallel interface for IQ data
- Performs subchannel mapping:
- Supports a slow C&M channel based on a serial HDLC interface at standard bit rates (240 Kbps, 480 Kbps,960 Kbps, and 1920 Kbps). The HDLC framer, if needed, must be provided as a separate IP core.
- Supports a fast C&M channel based on a serial Ethernet interface (84.48 Mbps max.) to the user logic, anon-standard rate MII Ethernet interface to a MAC, or a 100 Mbps MII interface to a PHY device. Accepts a user-selected pointer to the CPRI subchannel where the Ethernet link starts. The Ethernet MAC function isprovided as a separate IP core.
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- Performs synchronization and timing as defined in section 4.2.8 of the CPRI Specification
- Supports the L1 Inband Protocol
- Provides a parallel interface for merging vendor specific data into the CPRI frame
- Provides a start-up sequence state machine in hardware for both REC and RE nodes which performs:
- Synchronization and Rate Negotiation
- C&M Plane setup
- Performs Link Maintenance as defined in section 4.2.10 of the CPRI Specification:
- LOS detection
- LOF detection
- RAI indication
- Optional top-level template that implements user registers for control and status management
- Optional 8-bit register interface through the JTAG port
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Low Latency option for LatticeECP2M/S, LatticeECP3
The low latency CPRI core configuration supports all of the features specified for the basic core configuration with the following key exceptions/modifications:
- Supports 1228.8 Mbps and 2457.6 Mbps line bit rates only.
- 3G is supported in LatticeECP3 devices.
- FPGA bridge FIFOs in the SERDES/PCS block are bypassed in both the receive and transmit directions
- Logic blocks supporting receive direction 10b word alignment, 10b/8b decoding and core-violation detection inthe SERDES/PCS block are bypassed and the corresponding functions are implemented in FPGA gates

Resource Utilization
LatticeECP31
| Configuration |
SLICEs |
LUTs |
Registers |
sysMEM EBRs |
| Serial |
Low Latency |
1171 |
1374 |
1522 |
4 |
| Matched |
Low Latency |
1382 |
1737 |
1632 |
2 |
| Fixed |
Low Latency |
1476 |
1547 |
1691 |
6 |
LatticeECP2M/S1
| Configuration |
SLICEs |
LUTs |
Registers |
sysMEM EBRs |
| Serial |
Basic |
941 |
1257 |
1120 |
2 |
| Matched |
Basic |
1195 |
1678 |
1264 |
2 |
| Fixed |
Basic |
1294 |
1852 |
1318 |
6 |
| Serial |
Low Latency |
1428 |
1926 |
1429 |
2 |
| Matched |
Low Latency |
1668 |
2324 |
1576 |
2 |
| Fixed |
Low Latency |
1741 |
2455 |
1630 |
6 |
LatticeSC/M1
| Configuration |
SLICEs |
LUTs |
Registers |
sysMEM EBRs |
| Serial |
Basic |
932 |
1283 |
1123 |
2 |
| Matched |
Basic |
1186 |
1718 |
1267 |
2 |
| Fixed |
Basic |
1240 |
1822 |
1321 |
6 |
Demos
Ordering Information
| Family |
Part Number |
| LatticeECP3 |
CPRI-E3-U4 |
| LatticeECP2M/S |
CPRI-PM-U4 |
| LatticeSC/M |
CPRI-SC-U4 |
IP Version: 3.2
Evaluate: To download a full evaluation version of this IP, please go to the Lattice IP Server tab in the IPexpress Main Window. All ispLeverCORE IP modules available for download are visible on this tab.
Purchase: To find out how to purchase the CPRI IP Core, please contact your local Lattice Sales Office.
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