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Error Cannot Synthesize Dual-port Ram Logic

You may have to register before you can post: click the register link above to proceed. Our design requires 2 reads and 1 write in 1 clock cycle. This code contains some constants describing the FPGA type that is used. You can control all the paramters yourself. weblink

Reply tony says: 2011-02-01 at 03:46 thanks for your usefull work Dan, historically Altera memory access was no truly dual port, does this has changed in the latest generations? Conceivably, this is behavior that might be useful in a real design (maybe not a good design, but a design nonetheless). I have the Quartus II web edition Just putting some -- comments on the lines like this and it compiles again: PROCESS (iCLK) BEGIN IF (rising_edge(iCLK)) THEN -- Mise en mémoire Since it can't be mapped directly to a RAM, Quartus adds additional bypass logic (using extra logic-elements in the process).

Altera supports byte-enables on both simple and true dual-port memories. simulation in Icarus Verilog). Hot Network Questions Two-headed version of \Rightarrow or \implies What crime would be illegal to uncover in medieval Europe?

This exact behavior isn't directly supported by Xilinx's or Altera's block RAMs. Reply With Quote Page 1 of 3 123 Last Jump to page: Quick Navigation General Altera Discussion Top Site Areas Settings Private Messages Subscriptions Who's Online Search Forums Forums Home Forums Also the Quartus MegaWizard is a convenient tool to evaluate the possible configurations. To start viewing messages, select the forum that you want to visit from the selection below.

Because there is no conflict resolution circuitry built into M9K memory blocks, this results in unknown data being written to that location. ACTION: If you intend to infer the RAM into the hardware, refer to Chapter 6, "Recommended HDL Coding Styles," in the QuartusII Handbook, vol. 1., for examples of coding styles that ACTION: Remove any asynchronous or synchronous clear or reset logic associated with the RAM. http://quartushelp.altera.com/14.0/mergedProjects/msgs/msgs/einfer_cant_synthesize_dual_port_ram.htm Please try the request again.

If I change the code to PROCESS (iCLK) BEGIN IF(rising_edge(iCLK)) THEN -- Mise en mémoire du pixel ram(640*IdxC + PixX) <= PIXIN; -- Choix traitement IF (SWITCH='1') THEN PIXOUT <= ram(640*((IdxC If you use the same clock for the two clocks, the output is the old data from the address location. Anyway. RAMB8BWER in all configurations: A12–A6 including A4 cannot be the same.

so this is the reason i need two clocks. http://zet.aluzina.org/forums/viewtopic.php?f=5&t=229 what does it mean by "used to" in the context below? regards Ammar Reply With Quote September 23rd, 2010,06:31 AM #2 FvM View Profile View Forum Posts Altera Guru Join Date Dec 2007 Location Bochum Germany Posts 5,923 Rep Power 1 Re: asked 3 years ago viewed 1014 times active 3 years ago Related 2Altera Quartus - How do I simulate a different Entity1Can't synthesize my VHDL in Qsys1How to upgrade a Quartus

IN operator must be used with an iterable expression stdarg and printf() in C more hot questions question feed lang-vhdl about us tour help blog chat data legal privacy policy work http://haywirerobotics.com/error-cannot/error-cannot-open-an-http-server-socket-error-reported-errno-eacces.html A read/write on one port and a write operation from the other port at the same address is not allowed. Using current synthesis tools from Xilinx (ISE WebPack 12.2) and Altera (Quartus II Web Edition 10.0 SP1), it's now practical to write synthesizable device and vendor-independent Verilog code (or VHDL, if Cannot synthesize dual-port RAM logic "" (ID: 276001) CAUSE: In a Verilog Design File (.v) or VHDL Design File (.vhd), you specified logic that acts as RAM with at least two

so, where could be the problem now?? In VHDL I use the concurrent statement "if generate" to select the proper vendor specific code to instantiate vendor specific building blocks. Figuring out exactly the right sort of Verilog to get multiple tools to infer the block you want can be even trickier. check over here In READ_FIRST mode only, the dual-port block RAM has the additional restriction that addresses for port A and B cannot collide.

This is necessary for XST to infer it as dual-port. (I've got a post on infering dual-port RAM with XST as well, welcome to check it out.) Reply Pingback: how to but i get this error. In the synchronous process, the value for this inferred signal is not defined for the case that ends up in PIXOUT <= x"111".

thanks for your time.

Trying to place clock-enables on a true dual-port memory yields the distinctly unhelpful message "RAM logic is uninferred due to asynchronous read logic". Reply With Quote September 27th, 2010,03:12 AM #8 ammar View Profile View Forum Posts Altera Pupil Join Date May 2010 Location Germany Posts 19 Rep Power 1 Re: True Dual Port Reply Azhar says: 2013-05-31 at 12:12 I think, if one needed to use BRAMs then you could tie the writes and associated signals to 2 two port rams' write ports. share|improve this answer edited Jan 14 '13 at 0:38 answered Jan 13 '13 at 13:38 apalopohapa 6,32921428 add a comment| Your Answer draft saved draft discarded Sign up or log

Reply With Quote September 23rd, 2010,06:53 AM #3 ammar View Profile View Forum Posts Altera Pupil Join Date May 2010 Location Germany Posts 19 Rep Power 1 Re: True Dual Port The read-during-write behavior of a dual-clock RAM is undefined and may not match the behavior of the original design. Xilinx supports inferring clock-enables on all BRAM types. http://haywirerobotics.com/error-cannot/error-cannot-open-phone-communication-port.html clock-enables are always supported).

In cases where the write mode does not matter, which mode is best to default to? I use wrappers around everything that is vendor specific. any thoughts over this problem? Last edited by FvM; September 23rd, 2010 at 10:07 AM.

Product of all divisors=cube of number. Both Xilinx and Altera support inferring byte-enables, to a certain extent. For more fine-grained control, you can embed constraints in your source code (e.g. Have you done this before?

Good work! Altera only seems to support this on simpler forms of memories. Nonetheless, if you try to run this code through XST, it will happily infer a BRAM: Synthesizing (advanced) Unit . Use coding styles that allow Analysis & Synthesis to infer RAM.

Should work in a single process though. –Brian Drummond Jan 12 '13 at 16:07 I edited your comment back into the question so that it is readable. Constraints can also typically be specified in a UCF file. There are yet more caveats.. Reply Syeda Anisa Gohar says: 2013-08-31 at 00:57 Wow..

I can get it to work for single port RAMs but not dual port. There is, however, no risk of physical damage to the device. The last part missing is some automatic possibility to ask what kind of FPGA the synthesizer is targeting (As you normaly do with a C compiler where you can set preprocessor Both Xilinx and Altera support specifying the initial contents of inferred RAMs and ROMs using Verilog initial blocks with $readmemh statements.

list marked files in dired in another buffer Glassmapper fields displaying null despite correct item ID Locker Service: How to get the event target? Reply Mark McDougall says: 2010-11-18 at 13:58 I've been avoiding this sort of thing for exactly the reasons you guess I have! :) Nice work- thanks! I find it useful to infer (rather than instantiate) memories not only for portability, but also for reconfigurability based on parameters/generics (with some coarse constraints on what these parameters may be, When does “haben” push “nicht” to the end of the sentence?