Could you please provide me the PCB design guide for IFC interface of LS1021A Hi, On my board, IFC interface of LS1021A will directly connect to two Flash、two PHY with MCU interface and 2x buffer( SN74LVC16245A)。PCB routing will be very complicated. So, 1. What kind of routing topology could be accepted from SI point of view? 2. Could you please provide me the PCB design guide for IFC interface of LS1021A Thanks in advacnce! Best regards! Jason QorIQ LS1 Devices Re: Could you please provide me the PCB design guide for IFC interface of LS1021A Hi, June: Like below figure shown, my circuit is a little complicated. IFC bus will drive total 8x chips through some buffers. Cause IFC interface use asynchronous mode, the rate of IFC is not high. Do you have general route guide for IFC interface like ethernet one given me by Yiping.wang? Jason_in_job_0-1789111004993.pngJason_in_job_0-1789111004993.pngJason_in_job_0-1789111004993.png Thanks in advance! Best regards! Jason Re: Could you please provide me the PCB design guide for IFC interface of LS1021A Please share the details of your topology
1. Will the two SN74LVC16245A devices be used to buffer or isolate the IFC address/data bus?
2. What type of Flash devices will be connected to the IFC interface (NOR Flash, NAND Flash, etc.)?
3. How are the two PHY devices connected to the IFC interface? Are they using GPCM mode?
4. Could you please confirm the complete IFC loading? Is it comprised of two Flash devices and two MCU-interface PHY devices?
Thanks Re: Could you please provide me the PCB design guide for IFC interface of LS1021A We do not have a dedicated PCB routing guideline specifically for the LS1021A IFC interface.
Unlike high-speed interfaces such as DDR or Ethernet, the IFC is an asynchronous parallel interface, and the signal integrity considerations are highly dependent on the actual topology, loading, operating frequency, and PCB implementation. Therefore, NXP does not provide a dedicated IFC routing guide with universal layout rules.
In general, we recommend minimizing branch (stub) lengths, keeping the traces from the LS1021A to the latch and buffers as short as possible, and using buffers to isolate downstream loading whenever practical.
If practical, we recommend using a daisy-chain style routing with short stubs (for example, within approximately 1 inch / 25 mm where possible) rather than a large star-topology connection. For your topology, it is generally preferable to place the address latch closest to the LS1021A, followed by the boot Flash device, while keeping the buffers close enough to minimize loading on the IFC bus.
We also recommend maintaining a controlled single-ended impedance of 50 Ω ±10% for the IFC traces. The ±10% tolerance accounts for PCB fabrication variations, while the design target should ideally be within ±2%.
If signal integrity issues are observed during validation, source termination resistors (for example, 22 Ω to 33 Ω) at the LS1021A outputs may be considered based on the actual waveform measurements and PCB implementation.
For reference, please refer to AN4878 (LS1021A Design Checklist) and the TWR-LS1021A reference design.
Given the complexity of the topology and the number of attached loads, signal integrity (SI) simulation is also recommended to validate the routing topology, loading, and timing margins before finalizing the PCB design.
Thanks
記事全体を表示