2.8" tft from buydisplay.com

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xzeion

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If you get it working, I hope you'll post a photo or info about exactly how it needs to be connected.

While there's a lot of info on their website, somehow very little of it seems clear to me....
 
@PaulStoffregen:
According to the specs on their website, it seems to be pin-compatible with your library as far as you choose 4-wire-SPI for interface (see attached files). I will post the result in the next week when the display is here.

@stevech: I haven't ordered the font chip as I am using the fonts for the UTFT library. There are many of them on Henning Karlsen's website (http://www.henningkarlsen.com/electronics/r_fonts.php) and the Teensy 3.1 offers enough flash space to store them, at least for my application.



Reference.PNGPinConfig1.PNGPinConfig2.PNG
 
The font chip appears to be just a memory chip on the SPI bus. At least as far as I can tell from the not-so-detailed documentation on buydisplay.com. The ILI9341 has no provision to use a font chip directly, nor do any rendering on its own, like the RA8875 can. There's not any way I can see for the font chip to be actually connected directly to the ILI9341.

Reading bitmaps from a SPI chip would be much slower than simply storing them in Teensy's program memory!

My guess is they offer that font chip on the RA8875-based displays, where it actually is connected to the RA8875, so they decided to also put it on this one, where it can do little to no good (other than a good number of people will probably add it, increasing the price, unaware of its lack of real benefit).
 
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Then again, if you were using this display from something like an Adafruit Trinket, where you only have 6K of flash, maybe having fonts stored in an external memory chip could be useful?
 
PaulStoffregen said:
Then again, if you were using this display from something like an Adafruit Trinket, where you only have 6K of flash, maybe having fonts stored in an external memory chip could be useful?
Click to expand...

Though with the Trinket/Gemma, the bootloader takes 2.75K of flash, so you only have 5.25k left over for the user program, and 512 bytes for SDRAM. Other ATtiny85 chips like the Digispark have smaller bootloaders that only take 2k, so on a digispark, you would have 6k. I'm tired of dealing with those restrictions, which is why I'm awaiting the M0 Teensy. However, from your description, it looks more complicated than just switching chips, as you have to make sure the entire library set works.
 
With the M0-based board, you'll get 3 real hardware serial, real hardware SPI and I2C, 8 PWM, 13 ADC (same 12-13 bit performance as Teensy 3.1), and one 12 bit DAC. The USB is DMA-based, for excellent performance and full support for all the USB types Teensy 3.1 supports. The memory is 64K of flash and 8K of RAM, quite a bit less than Teensy 3.1, and of course the M0 doesn't have the heavy-lifting computational power of the M4... but it's still a world apart from the feature-poor experience of ATTINY.

There's also 7 hardware timers on the M0 chip... enough to provide very good compatibility with many Arduino libraries, and even to allow more combinations to work together than any AVR supports. Still a step down from the 12 timers on Teensy 3.1, but a good step up from 8 bit AVR.
 
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Font chip... I'd assumed that the LCD microprocessor could be told which font to use and then itself access the font chip.
 
PaulStoffregen said:
With the M0-based board, you'll get 3 real hardware serial, real hardware SPI and I2C, 8 PWM, 13 ADC (same 12-13 bit performance as Teensy 3.1), and one 12 bit DAC. The USB is DMA-based, for excellent performance and full support for all the USB types Teensy 3.1 supports. The memory is 64K of flash and 8K of RAM, quite a bit less than Teensy 3.1, and of course the M0 doesn't have the heavy-lifting computational power of the M4... but it's still a world apart from the feature-poor experience of ATTINY.

There's also 7 hardware timers on the M0 chip... enough to provide very good compatibility with many Arduino libraries, and even to allow more combinations to work together than any AVR supports. Still a step down from the 12 timers on Teensy 3.1, but a good step up from 8 bit AVR.
Click to expand...

How many SPIs?
 
Sure, there has to be a reason to buy the more expensive Teensy, but compared to the ATtiny85, it should have real USB serial I/O for debugging, I don't have to muck about with TinyWire.h instead of Wire.h, it has more than 5 pins, more data memory, more program memory, etc. I was rewriting my neopixel libraries that I use to eliminate the delays, using a state machine and a library to return when to do the next action, and the rewrite is bigger than the 5.25k of program space on the Trinket. I decided I don't care enough any more to shrink down the code to fit in the trinket. I tend to mostly only do microprocessor stuff for costume type flashy things, and at a $10 or so price point, it is more feasible to just leave the microprocessor in the piece, then trying to take it out, and go on to the next piece. That way, I can easily go back to an existing piece and not have to rebuild it once again. I could probably do it with a regular Teensy 3.1, but for some reason, the $20/piece is more of a psychological barrier.
 
Alright, the 3.2 inch module from buydisplay.com is here and works instant !
Connection for the Display itself:
VSS (P1): GND
VDD (P2): 5V (Jumper J1 Open) / 3.3V (J1 Closed)
RESET (P21): 3.3V (Active low)
LCD_CS (P23): Any CS Pin (2,6,9,10,15, 20-23)
LCD_SCL (P24): D13 (SCK) / D14 (ALT_SCK)
D/C (P25): Any CS Pin (2,6,9,10,15, 20-23)
LCD_SDI (P27): D11 (MOSI) / D7 (ALT_MOSI)
LCD_SDO (P28): D12 (MISO) / D8 (ALT_MISO)
BL_ONOFF (P29): Any Pin for Backlight toggle or 3.3V (HIGH) for constant on

Proof display running at 24MHz SPI Frequency and 144MHz CPU Clock:
(120MHz CPU rate & 30MHz SPI clock works also)

ILI9341.jpg

Using my portation of the UTFT Library.
Download here: https://www.dropbox.com/s/zn36b4n84xy2f35/UTFT.zip?dl=0
After InitLCD, set display rotation to setRotation(45) for correct view.

I can say that the display is very fast and only needs 5 digital pins for the basic configuration, which is a huge step forward in comparison to the 16-Bit SSD1289 module I used before.
 
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Thread revival of sorts here, but thanks very much for your pinout above. Got myself up and running with the ILI9341_t3 library. Was getting a touch confused by the pinouts on the datasheet I had, then soon discovered I was looking at the wrong version. >.>
 
Hello Max..,
Could you have a look at this sch - 2.8" TFT - Buydisplay - will this work ? and Im not shure which pin should be for TFT_DC ?
BuyDispy2.8.png

Thanks,
Mike
 
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