Search found 34 matches

by feluga
Tue Sep 15, 2020 8:17 pm
Forum: Projects
Topic: STM32F103C8 BluePill VGA Project
Replies: 37
Views: 9487

Re: STM32F103C8 BluePill VGA Project

Nice! That's some NES level 8bit graphic :-) Yes, that's the initial target. I'm trying to push it to the limit and get something between NES and SNES. DMA stream to ODR or BSSR? Is resolution stll 224x240? No, still direct bitbanging to ODR. DMA suffers from lack of BUS Matrix access priorization ...
by feluga
Tue Sep 15, 2020 1:26 pm
Forum: Projects
Topic: STM32F103C8 BluePill VGA Project
Replies: 37
Views: 9487

Re: STM32F103C8 BluePill VGA Project

Hopefully, 37.177 uS should be enough time to calculate next scanline. I also tested with 8bit data to ODR, and i still get minimum time of 250nS. Maybe SK32F103c8 clone issue? Well, at least i know a little more then yesterday :) Good luck with your library, you are doing good job so far! Thanks B...
by feluga
Fri Sep 04, 2020 6:27 pm
Forum: Projects
Topic: STM32F103C8 BluePill VGA Project
Replies: 37
Views: 9487

Re: STM32F103C8 BluePill VGA Project

Well, i have good news and bad news :) .. it was running great, but as i lowered overflow, for values lower then 18 (249,84nS) pulses started to have same width and stayed at around 250nS for any overflow less then 18. My guess it is 32bit DMA read-write + CPU time. Will test some day with 8bit val...
by feluga
Thu Sep 03, 2020 11:18 pm
Forum: Projects
Topic: STM32F103C8 BluePill VGA Project
Replies: 37
Views: 9487

Re: STM32F103C8 BluePill VGA Project

Here goes some links that may help on getting DMA+Timer --> GPIO to work: Some documentation about DMA and paralellism Check this: chapter 5 - DMA latency 5.3 Sharing the bus matrix with CPU AN2548 Application note - Using the STM32F0/F1/F3/Gx/Lx Series DMA controller Although this AN is not for F10...
by feluga
Thu Sep 03, 2020 9:20 pm
Forum: Projects
Topic: STM32F103C8 BluePill VGA Project
Replies: 37
Views: 9487

Re: STM32F103C8 BluePill VGA Project

I was thinking BSRR was good choice because it would be possible to use other ports. Yes, it's 32bit register, what i had in mind to use two buffers of 4*pixels bytes per line, and in interrupt use something like: -Set DMA to send 1st/2nd buffer (with few flags as "if" statement, and always same ex...
by feluga
Thu Sep 03, 2020 5:04 pm
Forum: Projects
Topic: STM32F103C8 BluePill VGA Project
Replies: 37
Views: 9487

Re: STM32F103C8 BluePill VGA Project

I have idea for full bitmap mode, i don't know is it possible to implement (you are using assembler, and only thing i can think of is timer triggering DMA transfer from memory to GPIO's BSSR register). One point is that BSSR is 32 bits register. Thus, it'll need something running to map bits into t...
by feluga
Thu Sep 03, 2020 2:59 pm
Forum: Projects
Topic: STM32F103C8 BluePill VGA Project
Replies: 37
Views: 9487

Re: STM32F103C8 BluePill VGA Project

Good question! I'm glad you asked it! The way I implemented is sort of a mix of what you just wrote. :D I'm just curious, did you implement full 224x240 bitmap mode? No, I draw pixel by pixel for the Sine curve in a 250ms interval in order to make a nice plotting animation. A 224x240 bitmap mode in ...
by feluga
Wed Sep 02, 2020 3:40 am
Forum: Projects
Topic: STM32F103C8 BluePill VGA Project
Replies: 37
Views: 9487

Re: STM32F103C8 BluePill VGA Project

More news on the development of BlueVGA Arduino Library! Working on adding pixel drawing functions to the library, always with a low footprint. The examples below use just about 4.5K RAM and about 22K Flash using STM32 Official Core. Example of a sketch that animates drawing a sine curve. It may ins...
by feluga
Sun Aug 23, 2020 9:09 pm
Forum: Ideas & suggestions
Topic: Bare metal STM32 programming
Replies: 16
Views: 3913

Re: Bare metal STM32 programming

As for the discussion about Bare Metal, I think it's a personal decision. Of course, there are many ways to program some STM32s beside using C or C++. Some higher end STM32 can be programmed using Python as even Java Script. I have seen people writing programs in Rust for the Blue Pill. Bare Metal i...
by feluga
Sat Aug 22, 2020 12:27 am
Forum: Ideas & suggestions
Topic: Bare metal STM32 programming
Replies: 16
Views: 3913

Re: Bare metal STM32 programming

My two cents on this topic: https://github.com/RoCorbera/BlueVGA/blob/master/src/bluevgadriver.c This is an arduino library that I built for driving VGA displays. This file uses Bare Metal programming using Arduino IDE for building it. It demonstrates how to use STM32F103 Registers directly in C cod...

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