Summary of Contents for Lattice Semiconductor ECP5
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ECP5 and ECP5-5G High-Speed I/O Interface Technical Note FPGA-TN-02035-1.3 October 2020...
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The information provided in this document is proprietary to Lattice Semiconductor, and Lattice reserves the right to make any changes to the information in this document or to any products at any time without notice.
DDR interfaces capture data on both the rising and falling edges of the clock, thus doubling the performance. ECP5 and ECP5-5G device I/O also have dedicated circuitry that is used along with the DDR I/O to support DDR2, DDR3, DDR3L, LPDDR2, and LPDDR3 SDRAM memory interfaces.
DQS strobe and up to 12 to 16 ports for DQ data and DM data mask signals. The number of DQS Lanes on the device is different for each device size. ECP5 and ECP5-5G devices support DQS lanes on the left and right sides of the device.
This section describes the various design guidelines used for building generic high-speed DDR interfaces in ECP5 and ECP5-5G devices. In additional to these guidelines, it is also required to follow the Interface Rules described for each type of interface, you need to find the interface you are building in the High-Speed DDR Interface Details section.
All of the DDR SDRAM interface transfers data at both the rising and falling edges of the clock. The I/O DDR registers in the ECP5 and ECP5-5G device can be used to support DDR2, DDR3, DDR3L, LPDDR2, and LPDDR3 memory interfaces.
ECP5 and ECP5-5G devices generate a DQS signal that is center aligned with the DQ, the data signal. This is accomplished by ensuring a DQS strobe is 90° shifted relative to the DQ data. The ECP5 and...
LPDDR2) outputs. In ECP5 and ECP5-5G devices, a DQS group consists of 12 to 16 I/O depending on the device and package selected to accommodate these DDR interface needs. ECP5 and ECP5-5G devices support DQS signals on the left and right sides of the device.
6.2.2. DLL-Compensated DQS Delay Elements The DQS to and from the memory is connected to the DQS delay element inside the ECP5 and ECP5-5G device. The DQS delay block receives the delay control code, DDRDEL, from the on-chip DDRDLL. The code generated by DDRDLL is connected to the DQSBUF circuit to perform 90°...
Due to the DQS round trip delay that includes PCB routing and I/O pad delays, proper positioning of the READ pulse is crucial for successful read operations. The ECP5 and ECP5-5G device DQSBUF block provides the dynamic READ pulse positioning function which allows the memory controller to locate the READ pulse to an appropriate timing window for the read operations by monitoring the positioning result.
6.2.6. Read Data Clock Domain Transfer Using Input FIFO Each IDDR module in the ECP5 and ECP5-5G device has a dedicated input FIFO to provide a safe clock domain transfer from the DQS domain to the ECLK or SCLK domain. The input FIFO is 8-level deep with 3-bit write and read pointers. It transfers the read data from the non-continuous DQS domain to the continuous ECLK.
ECP5-5G devices. ECP5 and ECP5-5G devices have dedicated DQS banks with the associated DQ pads. The left and right sides of an ECP5 and ECP5-5G device share an identical I/O structure. All of the memory interfaces can be implemented on these sides.
DDR3 SDRAM's ODT function. Do not locate any termination on the FPGA side. The ECP5 and ECP5-5G device has internal termination on DQ and DQS, which is dynamically controlled. Use the TERMINATION preference for DQ and DQS pads to enable the internal parallel termination to VCCIO/2.
DQS interface such as DDR2 with single ended strobe. However, a DQS signal must use the DQS/DQS# pads only. Data group signals (DQ, DQS, DM) can use any of the left and right sides of the ECP5 and ECP5-5G device as long as they keep the DQS-DQ association rule. ...
Place the DQS groups for data implementation starting from the middle of the (right or left) edge of the ECP5 and ECP5-5G device. Allow a corner DQS group to be used as a data group only when necessary to implement the required width.
Technical Note 7.1. Configuring DDR Modules in Clarity Designer The catalog section of Clarity Design lists all the DDR architecture modules available on ECP5 and ECP5-5G. All the DDR modules are located under Architecture Modules – I/O. This includes: ...
ECP5 and ECP5-5G High-Speed I/O Interface Technical Note There is an additional tab called Advanced Settings for the ECP5 and ECP5-5G device that can be used to adjust the default DQS Read and Write Delay settings. Figure 7.12. DDR_MEM Advanced Settings Tab Figure 7.8...
8.7. Generic DDR Input and Output Primitives The ECP5 and ECP5-5G device IDDR/ODDR modules support 2:1, 4:1 and 7:1 gearing modes on the left and right sides only. IDDR/ODDR modules on the top (and bottom for non-SERDES parts) only supports 2:1 due to lack of Edge Clocks.
Note: Default value is set based on device characterization to achieve the 90° phase shift. 8.11. Input and Output Memory DDR Primitives The ECP5 and ECP5-5G device IDDR/ODDR modules support 4:1 (2x) gearing mode that are used to implement the memory functions.
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