PaulStoffregen
Well-known member
I'm considering making a PJRC product for a 3.5 inch TFT touchscreen display with 480x320 resolution. Conceptually, it would be pretty similar to this Adafruit product, with SPI interface on the bottom side and 8 bit parallel interface on the top.
So here's a thread to discuss details....
If we do this, which is still a pretty big "if" at this point, PJRC will almost certainly have a custom display made in China, and we'd assemble it onto a breakout board here in the USA. I've already talked with a few companies who would put together the display part from standard materials, but with the flex PCB part customized for us. That's important, because almost all the ones readily available support only 16 bit parallel mode. This also means we can get access to signals not commonly brought out from other displays, like the TE output or PWM backlight control pin.
A couple major decisions to make are the type of TFT and touchscreen. IPS displays are available, which offer superior color range and wide viewing angles. Normal TN types, like we have now with the common 2.8 inch side, are less expensive. Likewise, touchscreens come in cheap resistive which detects only a single touch point and requires significant pressure, or more expensive capacitive touch that works similar to cell phones and tablets. Different touch controller chips can be used, some detecting 2 touch points, others up to 5 points.
Tentatively, the controller chip is looking very likely to be ILI9488. If capacitive touch is used, the touch controller may end up being FT6206 or FT6236.
The pinout is also undecided, but my general goal is to have one side require as few signals as possible for easy DIY connection and the other side offer 8 bit parallel for higher performance. I'm debating whether to add extra circuitry like a reset chip, backlight control or other nice features, which aren't commonly found on the other breakouts.
So here's a thread to discuss details....
If we do this, which is still a pretty big "if" at this point, PJRC will almost certainly have a custom display made in China, and we'd assemble it onto a breakout board here in the USA. I've already talked with a few companies who would put together the display part from standard materials, but with the flex PCB part customized for us. That's important, because almost all the ones readily available support only 16 bit parallel mode. This also means we can get access to signals not commonly brought out from other displays, like the TE output or PWM backlight control pin.
A couple major decisions to make are the type of TFT and touchscreen. IPS displays are available, which offer superior color range and wide viewing angles. Normal TN types, like we have now with the common 2.8 inch side, are less expensive. Likewise, touchscreens come in cheap resistive which detects only a single touch point and requires significant pressure, or more expensive capacitive touch that works similar to cell phones and tablets. Different touch controller chips can be used, some detecting 2 touch points, others up to 5 points.
Tentatively, the controller chip is looking very likely to be ILI9488. If capacitive touch is used, the touch controller may end up being FT6206 or FT6236.
The pinout is also undecided, but my general goal is to have one side require as few signals as possible for easy DIY connection and the other side offer 8 bit parallel for higher performance. I'm debating whether to add extra circuitry like a reset chip, backlight control or other nice features, which aren't commonly found on the other breakouts.