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Discussion about software development for the old-school Gameboys, ranging from the "Gray brick" to Gameboy Color
(Launched in 2008)

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#1 2017-07-24 17:44:47

svendahlstrand
Member
Registered: 2016-12-07
Posts: 17
Website

Take a screenshot by sniffing the LCD data bus

Hello, everyone!

Yesterday I managed to take some screenshots the hard way, using a logic analyzer to sniff the data bus going to the Game Boy LCD. It has been done many a time before but was a fun challenge for me. I photographed and documented the process and wrote a little program that takes the exported data from Saleae's Logic Software to generates a screenshot.

http://i.imgur.com/RelRajM.jpg

In the picture above you can see a photograph of my Game Boy screen (to the left) compared with the final screenshot (to the right) constructed from the data I captured using my logic analyzer.

I hope this will help someone else like me, who are just getting started with the hardware side of Game Boy.

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#2 2017-07-24 18:48:03

nitro2k01
Administrator
Registered: 2008-02-22
Posts: 161

Re: Take a screenshot by sniffing the LCD data bus

Cool stuff. 50 MS/s seems like way overkill. I don't know if you're planning for a streaming version, but if so you may want to choose a lower rate.


Blog: Gameboy Genius
"A journey of a thousand miles begins with one small step"
Old Chinese Proverb

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#3 2017-07-25 03:19:48

svendahlstrand
Member
Registered: 2016-12-07
Posts: 17
Website

Re: Take a screenshot by sniffing the LCD data bus

nitro2k01 wrote:

50 MS/s seems like way overkill.

Yes, you're absolutely right. It's just me being lazy and leaving the default setting. smile Saleae recommends at least 4× oversampling for digital signals so 16 MS/s should be enough for capturing the pixel clock at 4 MHz.

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#4 2017-08-08 10:46:05

bbsfoo
Member
Registered: 2016-02-08
Posts: 15

Re: Take a screenshot by sniffing the LCD data bus

can do some research about the gbc's lcd?

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