ColorFormats example shows low colour depth on STM32F746

Question

I succesfully built and uploaded the ColorFormats example using EW Evaluation edition on the STM32F746 discovery board

What I notice is a lower color depth on the displayed graphics.( see attachment photo).. you can see that the colorscale is not smooth and it looks segmented.

my understanding is that the DISCO TFT should support 16Mcolours.

any suggestion?

br

-dan

 

Answer 1

Hi Dan,

I just verified the sample again and there appear no steps within the color gradients. It looks exactly like in the Prototyper window.

Just to be sure: Did you modify the makefile or the provided project? It seems to me, that you are using the generated code for RGBA8888 - but the display settings for RGBA4444.

Manfred

Comments

Hi Manfred,

the Makefile is untouched, and it's the original version provided by EW.

• within EW the target profile RGBA8888 uses the platform package STM.STM32.RGBA8888
• the command line I execute is the following: make colorformat=RGBA8888
• For your convenience, please find attached the makefile from the EW evaluation

what else can I check?

br

-dan

 

 

---

Please try the attached binary of the RGBA8888 color format demo for STM32F746 discovery - is it o.k. on your target?

Btw: which version of STM32 F7 cube firmware are you using?

---

OK,  here my findings:

• I uploaded your compiled .bin file and the issue unfortunately persists
• the firmware I have on the board is is V2.J27.M15
• I attach a photo of the STM32 case with the model and production batch date. Board version is MB11918

I cant figure out or imagine what the issue could be

any thoughts/idea?

-dan

 

 

 

---

Hi,

the board I used is MB1191B, firmware now updated to V2.J27.M15 - and it looks perfect.

Since you are using the same binary file, I assume some hardware issue...

Can you verify that on another board?

Manfred.

---

sent you a PM.

-dan

---

Hi Manfred,

before asking ST directly for support, I would like to provide you with the .bin code that I generated using EW evaluation on my laptop

http://ask.embedded-wizard.de/?qa=blob&qa_blobid=6598909226792276992

could you please confirm if this runs ok on your DISCO board?

I assume that if this works on yours it would mean there is an HW issue

thanks for your help

much appreciated

-dan

 

---

Hi Dan,

the binary file that you provided works also fine on my board - so it is very likely that there is some hardware issue on your discovery board... Please try with another hardware.

Best regards,

Manfred.

---

Hi Manfred,

I just got a 2 new boards and it works fine on them :)

Will report back as soon as I get the replacement board from ST, and report on the finding.

br

-dan

 

---

Hi Manfred,

I just got a stm32f746 disco replacement board from ST, and I can confirm it works perfectly now.

Will post any findings in the future should this be relevant for the community.

thanks for your help

-dan