diagrom showing 0 fastmem on new board

TF530 - 63030 + RAM Board

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oggie
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Re: diagrom showing 0 fastmem on new board

Post by oggie » Sat Dec 28, 2019 3:25 pm

Mine does have an FPU in it.

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8 Bit Dreams
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Re: diagrom showing 0 fastmem on new board

Post by 8 Bit Dreams » Sun Dec 29, 2019 11:24 am

oggie wrote:
Sat Dec 28, 2019 2:20 pm

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
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oggie
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Re: diagrom showing 0 fastmem on new board

Post by oggie » Sun Dec 29, 2019 2:04 pm

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?

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8 Bit Dreams
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Re: diagrom showing 0 fastmem on new board

Post by 8 Bit Dreams » Sun Dec 29, 2019 2:37 pm

don't have any TF530's to make a photo,
i mean one on the top side beneath CPU socket
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oggie
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Re: diagrom showing 0 fastmem on new board

Post by oggie » Sun Dec 29, 2019 7:36 pm

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

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8 Bit Dreams
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Re: diagrom showing 0 fastmem on new board

Post by 8 Bit Dreams » Sun Dec 29, 2019 8:55 pm

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:
tf530.jpg
tf530.jpg (84.8 KiB) Viewed 1205 times
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
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oggie
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Re: diagrom showing 0 fastmem on new board

Post by oggie » Sun Dec 29, 2019 9:41 pm

yes. I didn't solder that one.

oggie
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Re: diagrom showing 0 fastmem on new board

Post by oggie » Mon Dec 30, 2019 12:10 am

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.

oggie
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Re: diagrom showing 0 fastmem on new board

Post by oggie » Thu Jan 16, 2020 12:22 am

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....

dalek
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Re: diagrom showing 0 fastmem on new board

Post by dalek » Thu Jan 16, 2020 5:26 am

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.

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