25-11-2018, 07:06 PM
Frank, what sort of scope do you have? Unless it's 200MHz+ bandwidth it will be telling you possibly significant lies about the waveform. If it's less than 100MHz BW it will be potentially telling big lies.
I'm not familiar with the Altera tools but at the clock speeds you're using it's essential to use them to specify clock speeds. So for the older ISE Xilinx tools for a 200MHz clock I'd put the following in the UCF file:
NET "myclock" TNM_NET = thisfastclock;
TIMESPEC TS_thisfastclock = PERIOD "myclock" 5ns HIGH 50%;
The tools would then try to ensure that anything working with that clock will meet the timing requirements. They will also report paths where the requirements are not met.
To meet those sorts of speeds you need maximum pipelining. So multipliers will need internal registers, arithmetic and other logic must have a register after just about every operation.
Unless you're going to fill up the device with a lot of logic running at 200MHz you shouldn't be in lunatic land. I run the fairly old Spartan 3 series devices witha lot of stuff running at 148.5MHz. As the device fills up it's tight but manageable. Not into head banging yet.
I'm not familiar with the Altera tools but at the clock speeds you're using it's essential to use them to specify clock speeds. So for the older ISE Xilinx tools for a 200MHz clock I'd put the following in the UCF file:
NET "myclock" TNM_NET = thisfastclock;
TIMESPEC TS_thisfastclock = PERIOD "myclock" 5ns HIGH 50%;
The tools would then try to ensure that anything working with that clock will meet the timing requirements. They will also report paths where the requirements are not met.
To meet those sorts of speeds you need maximum pipelining. So multipliers will need internal registers, arithmetic and other logic must have a register after just about every operation.
Unless you're going to fill up the device with a lot of logic running at 200MHz you shouldn't be in lunatic land. I run the fairly old Spartan 3 series devices witha lot of stuff running at 148.5MHz. As the device fills up it's tight but manageable. Not into head banging yet.
www.borinsky.co.uk Jeffrey Borinsky www.becg.tv
