TFT 320x240 16bit to 8bit data mod

External hardware connected to the STM32 board
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Pito
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TFT 320x240 16bit to 8bit data mod

Post by Pito » Thu Jun 29, 2017 10:21 pm

I am going to mod my 320x240 TFT display (blue pcb, touch, 40pin connector) configured for 16bit to 8bit data.
http://www.elecfreaks.com/wiki/index.ph ... een_Module

So far I gently removed the white plastic TFT part of the display (it was "glued" to the pcb with an adhesive tape), and there is a flex pcb with a dozen of ceramic capacitors and 3 resistors marked R1,2,3 on the flex pcb.

My understanding is the SSD1289 display is configured by those 3 resistors (or maybe by 2) to the 16bit mode, while removing some of them I can configure it for 8 bit data.

The big Q is which ones :) I cannot find any description/datasheet on the net so far.
The info on the flex pcb is
TFT8K0998FPC-A1-E
TRULY-C

See below the picture. Any hint on a datasheet for that module? I've got the SSD1289 datasheet which shows the config pins settings for all possible modes, but it is impossible to track them down to the flex pcb..
TFT8K0998FPC_A1_E.JPG
TFT8K0998FPC_A1_E.JPG (54.4 KiB) Viewed 345 times
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zmemw16
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Re: TFT 320x240 16bit to 8bit data mod

Post by zmemw16 » Thu Jun 29, 2017 11:51 pm

which ones are fitted ?
zero ohm links ?
what modes match that in 16bit mode ? of course no bets they map directly to the mode lines or even to the modes :)
can you find a ground connection ?
shorted to gnd, open for internal pullup ?

new pic with more width ?

stephen

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Pito
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Re: TFT 320x240 16bit to 8bit data mod

Post by Pito » Fri Jun 30, 2017 12:09 am

The schematics of the pin layout of the flex connector is known. No config pins on it. Not known is the schematics with the Cs and Rs however.

The R3 seems to be 0 ohm bridge from Vcc to the C10 and into the tft.

The R2 is 0 ohm grounded, the zero signal goes into tft.

The R1 is 5k connected to the VCR1 which seems to be a capacitor blocking maybe Vcc something (it is not the Vcc), the other side goes to RESET pin at the flex connector..

So the only config Rs seems to be the R2 and maybe R1.

There are the PS0..PS3 pins on the SSD1289 die, which set the tft modi. Current setting is 16bit 8080 mode.

Assuming R1=1 and R2=0, the R1=>PS0 and R2=>PS1
TFT settings2.JPG
TFT settings2.JPG (70.12 KiB) Viewed 325 times
The Data Bus in the table means the SSD1289 die data pins which maps to D0-D15 on the pcb, the 8bit mode will work with D0-7.
Last edited by Pito on Fri Jun 30, 2017 8:11 am, edited 3 times in total.
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david.prentice
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Re: TFT 320x240 16bit to 8bit data mod

Post by david.prentice » Fri Jun 30, 2017 7:18 am

You want to change 8080-16 (1001) to 8080-8 (1000)

This implies that any existing jumper is currently set high. i.e. PS0 pin.
And you would need to set low.

Some Panels have a physical 0R that you remove from one position and place in another position. e.g. it connects to either 3.3V or 0V.

If your controller has an internal pullup, you would only need to add an 0R to 0V. i.e. you would see an empty footprint for this 0R.
It is possible (but VERY unlikely) that the controller has an internal pulldown.

I suggest that you Google the model number of this Panel. Find the official documentation.

TFTs are fairly cheap nowadays. It does not look like your Panel can be changed. You can still use it with a Mega2560 or Due.
Buy a new 8-bit display for your STM32.

David.

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Pito
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Re: TFT 320x240 16bit to 8bit data mod

Post by Pito » Fri Jun 30, 2017 7:48 am

I suggest that you Google the model number of this Panel. Find the official documentation.
A good hint :)
As I wrote above, I got the panel doc, it does not list the stuff around the Cs and Rs on the flex board..
Updated above with new findings.
Flex connector layout.JPG
Flex connector layout.JPG (27.65 KiB) Viewed 292 times
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david.prentice
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Re: TFT 320x240 16bit to 8bit data mod

Post by david.prentice » Fri Jun 30, 2017 3:33 pm

I would not expect to see the PS# pins on the flexi ribbon (called IM# on most controllers)

Your R1, R2, R3 descriptions do not offer any hope. You have no empty footprints.
I would just buy another module.

David.

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