exxos's Atari, Amiga & retro forum

Mine does have an FPU in it.

oggie wrote: 28 Dec 2019 14:20
Is there a known issue that it can't do 40MHz?

TF530 works fine @40Mhz, seems to me You have a problem on ram cpld.

Wich Revision do You have? On rev.3 there is a 0603 cap beneath CPU that doesn't need to be installed, if You do - card will not work

It's a rev3.
I did install it in both boards, and it works fine in the 30MHz one:

https://photos.app.goo.gl/KpW9vDqXzvmVW9QG6

From github page:
2 0.1uF 0.1UF-25V(+80/-20%) 0603-CAP C16, C17 CAP-00810

So I should have only installed the one beside the FPU?

don't have any TF530's to make a photo,
i mean one on the top side beneath CPU socket

There isn't one on the topside under the cpu for rev3:
https://github.com/terriblefire/tf530/b ... v3_top.png

sorry, gave You wrong information, it is not beneath CPU its near RAM cpld, haven't built these for a year now... :oops:

Found this picture in net: this one doesn't need to be soldered on!!

resistors need to be 1k - 2k, same for RNs 1k - 2k,
i used 2K on my builds

yes. I didn't solder that one.

All my resistors are 1K BTW.

So I happened to have a spare 40MHz cpu. I installed it as well as redoing a few solder joints.

I don't see the strange artifacts on the screen anymore, and I'm able to successfully run a fastmem test of all 2mb, but the moment it completes in daigrom and I hit the esc key to go back to the main menu, it locks up.

It's weird that it's able to complete the fastmem test successfully every time though.

I don't have a lot of free time, so I finally found time to look at this again. After retrying solder joints etc and every other suggestion, I decided to put in a 33MHz crystal instead of the 40MHz one. Guess what? It's stable at 33MHz....

So underclocked it works. I don't have a spare 40MHz FPU to see if it's the culprit at 40MHz however. I've swappped the CPU and it still had the issue, so I'm starting to think my FPU is a fake....

The recent lots of 40Mhz FPUs from China bay I've found to be very hit and miss. From the ones I've got, I reckon around 1 in 3 don't do 40MHz, and the printing wipes away easily when rubbed with IPA, indicating a relabelled part.