CH341A Programmer 3.3V Fix | Voltlog #318

Welcome to a new Voltlog, if you watched the previous mailbag video I showed getting this CH341 programmer tool for EEPROMS and FLASH chips and my viewers were quick to point out this actually has a design problem regarding the voltage levels it puts out. So it appears there is a 3.3V regulator on board for providing power to the eeprom or flash chip via the zif socket but the CH341 itself is running at 5V which means it outputs 5V signals on the SPI bus.

Someone has reverse engineered this little board and put together a schematic which clearly shows pin 28 VCC connected to 5V but I want to make sure nothing has changed and this still present. And checking with a multimeter, pin 28 is still connected to 5V USB.

Connecting a 3.3V rated part for programming might result in damaging that part. You might get lucky, you might have a chip that will tolerate that but in general that’s bad practice and so we’re going to attempt to fix it by simply cutting the 5V line going into the CH341 pin 28 and supplying it with 3.3V from the onboard regulator instead. And the datasheet also specifies that V3 pin 9 should be connected to VCC and 3.3V as well.

InTheMail | Voltlog #317

Welcome to a new InTheMail, the series that will touch both your passion for electronics and your bank account at the same time. We have a selection of different electronics related items in this mailbag video and I’m going to start with this 2.2 inch TFT panel which I got for the Gopher NPS1601 project, as you may know I am working together with other people to produce an open-source plug&play replacement control panel. This is a bit of a spoiler but something like this 2.2 inch panel is an option we are considering with the biggest decision factor being available space on the front panel, as you know the NPS1601 has quite a compact form factor and there are other things that need to fit in there like rotary encoders and output jacks.

This particular panel has the ILI9225 driver IC and apparently 176×220 pixels resolution. When I ordered this it was labeled differently with ILI9341 and 240×320 resolution so they must have made a mistake when shipping this to me. After a bit of googling, it appears there are indeed two variants of this module floating around, they look almost identical, same form factor but use different lcd panels. This is one of those situations where Murphy got me right when I needed to get this part faster and couldn’t wait for anymore delays. Luckily I have another order placed a few weeks after this one so I’ll wait and see how that one shows up.