Guru
Joined: 11/02/2018
Location: AustraliaPosts: 2247
| Posted: 01:42am 30 Nov 2022 |
Blit, Pixel() and Save Image all need to read data from the screen and thus need SDO (Serial Data Out).
The 680R only provide partial isolation but everyone else has found it good enough to get touch working as the touch chip can easily supply the 4.5mA that the 680R draws.
SD cards can be a bit fussier, so some form of switch is needed to turn SDO off when the SD card is in use.
Are you certain all the breadboard connections are perfect? No one else is having this much trouble.
Try the transistor one here.
https://www.thebackshed.com/forum/ViewTopic.php?FID=16&TID=15214&LastEntry=Y#194594#194371
I will experiment with other methods.
Edit
Other Methods. Both of these pass all tests. Just about all normal optocouplers should be ok.
Otherwise I can come over and have a look at it. Just send the airfare, business class will be adequate.
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Edited 2022-11-30 17:45 by phil99