TF536 Rev2 Gets Hot

[terriblefire]

The only option available to me is this..

https://www.xilinx.com/support/answers/5175.html

Keep in mind i was a hairs width away from not releasing this board and consigning it to the bin. I've never seen any issues with it myself but that option has been turned off since the latter rev1s as it seemed to be the root cause of AlenPPC's instability.

[PaulJ_2.0]

Ok quick update.
It seems like the batch of CPLD I got do indeed run warm.
I swapped over the CPLD from my Rev1 and it runs cooler in the Rev2. It looks like I had 7.5ns variant in the Rev1 and the new batch are 10ns and run warmer. It's not an issue since the firmware change though, as the 10ns ones run cooler than before, just a heads up for completion of the thread.

[terriblefire]

Ok quick update.
It seems like the batch of CPLD I got do indeed run warm.
I swapped over the CPLD from my Rev1 and it runs cooler in the Rev2. It looks like I had 7.5ns variant in the Rev1 and the new batch are 10ns and run warmer. It's not an issue since the firmware change though, as the 10ns ones run cooler than before, just a heads up for completion of the thread.

Thats interesting. We are running those little guys hard. Although they're rated to about 133Mhz in the 10ns spec.

[alenppc]

I think this may depend on the CPLD batch. None of mine are running hot and I am using 10ns. But most likely the temperature will be within the specs.

[richx]

What are some of the batch date codes for the hot (Edit: 40C is cool) vs cooler? Can't tell from the pictures.

The spec has fSYSTEM=100MHz for the -10 and 125MHz for -7. What's running at 100MHz on the TF536, is it just internal CPLD or is the memory at 100MHz?

[terriblefire]

What are some of the batch date codes for the 40Cs vs cooler? Can't tell from the pictures.

The spec has fSYSTEM=100MHz for the -10 and 125MHz for -7. What's running at 100MHz on the TF536, is it just internal CPLD or is the memory at 100MHz?

The main clock crystal is 100Mhz.

[richx]

The main clock crystal is 100Mhz.

Right, how is it used, is it just for the CPLD logic and memory is accessed at less than 50MHz?

[terriblefire]

The main clock crystal is 100Mhz.

Right, how is it used, is it just for the CPLD logic and memory is accessed at less than 50MHz?

Everything in the CPLD is sync'd with it. so all flip flops are driven with it. Hence my previous answer. The CPLD runs at 100Mhz.

[richx]

Everything in the CPLD is sync'd with it. so all flip flops are driven with it. Hence my previous answer. The CPLD runs at 100Mhz.

Ok, didn’t know if SDRAM was double clocked. Is it same on the 360/1260, one CPLD is 2x the CPU frequency, and other is 1x?

[terriblefire]

Everything in the CPLD is sync'd with it. so all flip flops are driven with it. Hence my previous answer. The CPLD runs at 100Mhz.

Ok, didn’t know if SDRAM was double clocked.

It doesnt matter to CPLD temp. The global clock fabric is 100Mhz. So the speed of the ram is mostly irrelevant.