Search found 1951 matches

by stevestrong
Tue Jan 10, 2017 9:10 am
Forum: Libraries & Hardware
Topic: Lib for ILI9486 - 3.5 inch 480x320 touch TFT for RPi
Replies: 178
Views: 12538

Re: Lib for ILI9486 - 3.5 inch 480x320 touch TFT for RPi

There are two different cases: 1. the window address setting for the following data I do this in single 8 bit accesses, wherein I optimized the CS and Control/data pin setting within one BSRR register access. This optimization I had to remove, because the WR strobe signal will be either generated at...
by stevestrong
Mon Jan 09, 2017 9:25 pm
Forum: Libraries & Hardware
Topic: Lib for ILI9486 - 3.5 inch 480x320 touch TFT for RPi
Replies: 178
Views: 12538

Re: Lib for ILI9486 - 3.5 inch 480x320 touch TFT for RPi

OK. Forget the spec... The scope clearly shows that the 4040 has huge propagation delay (around 40ns !!), which is an SPI clock period at 25MHz! Thus, we should not wonder that everything above 24MHz will not work... Now I used some of the free inverter gates from the on-board HC04 chip to delay the...
by stevestrong
Mon Jan 09, 2017 4:07 pm
Forum: Libraries & Hardware
Topic: Lib for ILI9486 - 3.5 inch 480x320 touch TFT for RPi
Replies: 178
Views: 12538

Re: Lib for ILI9486 - 3.5 inch 480x320 touch TFT for RPi

David, sorry, what is tDST? I couldn't find it in the specs of 74HC4040, and 74HC4094. I was talking about tPD, tPLH/tPHL (propagation delays) between clock input and data output. The minimum pulse width tW, which would limit the input clock frequency, are for both 4040 and 4094 around 10ns (typical...
by stevestrong
Mon Jan 09, 2017 1:47 pm
Forum: Libraries & Hardware
Topic: Lib for ILI9486 - 3.5 inch 480x320 touch TFT for RPi
Replies: 178
Views: 12538

Re: Lib for ILI9486 - 3.5 inch 480x320 touch TFT for RPi

@Squonk42, sorry, but I don't see how this RC combination could produce a "negative" shift... Once the signal is too much delayed, I don't think this network can bring it back couple of nanoseconds. Or do you have some simulation results which would proof the contrary? EDIT I think the scope of the ...
by stevestrong
Mon Jan 09, 2017 10:50 am
Forum: Libraries & Hardware
Topic: Lib for ILI9486 - 3.5 inch 480x320 touch TFT for RPi
Replies: 178
Views: 12538

Re: Lib for ILI9486 - 3.5 inch 480x320 touch TFT for RPi

David, I agree that the optimal solution would be the maximal CPU freq. combined with max. supported SPI clock. Unfortunately, this is not always possible, as in case of generic F103. My desk is at ~20°C. The HC chips would work fine at 28MHz, the problem is rather the signal propagation delay throu...
by stevestrong
Mon Jan 09, 2017 10:38 am
Forum: General discussion
Topic: Guide for under- and over-clocking the blue-pill needed
Replies: 39
Views: 1892

Re: Guide for under- and over-clocking the blue-pill needed

That was my original idea: to have a place where it is shown what to do (step-by-step for dummies like me) if one needs to over(/under)clock... This makes any further change in repo obsolete, even more because then the USB upload would be not functional, causing more headache then solving problems, ...
by stevestrong
Mon Jan 09, 2017 10:31 am
Forum: STM32F103 Boards
Topic: Execute from external SRAM
Replies: 151
Views: 11414

Re: Execute from external SRAM

Pito wrote:Also the user APP usually ends with an endless loop.. Or can we stop it with CTRL_Q for example ?? :)
And I thought a main loop, or any usual "int my_function()" would end normally with a "return (int);" :?
What about collecting all the info on a wiki page?
by stevestrong
Mon Jan 09, 2017 9:48 am
Forum: STM32F103 Boards
Topic: Execute from external SRAM
Replies: 151
Views: 11414

Re: Execute from external SRAM

Just as a layman for return from RAM App to Flash: wouldn't be this handled automatically by the CPU when returning from

Code: Select all

Jump_To_Application();
?
by stevestrong
Sun Jan 08, 2017 9:34 pm
Forum: General discussion
Topic: Guide for under- and over-clocking the blue-pill needed
Replies: 39
Views: 1892

Re: Guide for under- and over-clocking the blue-pill needed

RogerClark wrote: Overall however, as the F4 boards are now becomming a lot cheaper and STM's F4 core will be here some time this year, I hope ;-), anyone wanting higher speeds would be better of overclocking an F4 board.
Yeah, I also hope that my F4 boards will finally manage to get out from the drawer... 8-)
by stevestrong
Sun Jan 08, 2017 9:31 pm
Forum: Libraries & Hardware
Topic: Lib for ILI9486 - 3.5 inch 480x320 touch TFT for RPi
Replies: 178
Views: 12538

Re: Lib for ILI9486 - 3.5 inch 480x320 touch TFT for RPi

The funny part is, some of the graphicstests (text, lines and all outlines, where many single pixel writes take place) runs better with lower SPI clock but higher CPU frequency, than vice versa. OTOH, obviously, large block fillings are faster with higher SPI clock, where the CPU frequency does not ...