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VGA driver using PIO and DMA on the RP2040

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Re: VGA driver using PIO and DMA on the RP2040

#11

Post by andrewstuart »

raphlinus wrote: post #9
andrewstuart wrote: post #7

Related: Adafruit Feather RP2040 with HDMI Output Port https://youtu.be/Nsvf5gnYErs https://www.adafruit.com/product/5710 Generating PAL https://hackaday.com/2023/01/24/generating-pal-video-with-a-...

I have the Adafruit DVI board and have been hacking on it some. It's more fun than should be allowed. There's a project to get this running using Rust[1]. Currently it outputs the blue channel with sync, but has trouble with the other two channels. I don't have a hardware lab with scope, logic analyzer, etc., so it's not easy for me to debug. In the meantime, I've been doing some experiments in the C codebase as well…

Be nice if the board had wireless built in, though I believe adafruit provides a clip on wireless module.

Re: VGA driver using PIO and DMA on the RP2040

#12

Post by vardump »

_Microft wrote: post #2

OT but a question I'm curious about: what features would people who have a lot of experience with the RP2040 like to see on a successor?

Memory mappable PSRAM support would be nice.

Or more pins and more PIO as well.

I guess more SRAM wouldn't hurt either.

Re: VGA driver using PIO and DMA on the RP2040

#13

Post by polpo »

_Microft wrote: post #2

OT but a question I'm curious about: what features would people who have a lot of experience with the RP2040 like to see on a successor?

More than 32 instructions per PIO block: my main current project (PicoGUS) uses 32 instructions on one PIO block and 31 on the other to handle ISA IO, ISA DMA, I2S audio out, and SPI PSRAM access. Having more would let me cut a few less corners in how ISA is handled.

More/more flexible PIO instructions: branching is very limited, you can only arbitrarily SET up to 5 pins or pindirs at once (increasing to 8 would be a godsend), stalling with a sideset repeatedly executes the sideset, etc... I could go on.

Memory mapped PSRAM: I made a library to assist with accessing SPI PSRAM but it's still just functions to get/set groups of bytes. An intelligent cache around it would also mitigate the much higher latency of accessing PSRAM as well.

More SRAM: everyone can always use more RAM!

More GPIOs: everyone can always use more GPIOs!

Re: VGA driver using PIO and DMA on the RP2040

#14

Post by mtreis86 »

_Microft wrote: post #2

OT but a question I'm curious about: what features would people who have a lot of experience with the RP2040 like to see on a successor?

Better power consumption, especially in deep sleep. Make waking up cheap too, especially for some IOT purposes, like grabbing a sensor reading every couple minutes and storing it in a queue for future burst transmission. Optimize for that sorta thing. Measure in nanoamps.

Re: VGA driver using PIO and DMA on the RP2040

#16

Post by duskwuff »

happycube wrote: post #5
_Microft wrote: post #2

OT but a question I'm curious about: what features would people who have a lot of experience with the RP2040 like to see on a successor?

I haven't done a lot per se, but 480Mb USB would be nice.

USBHS is fairly hard to support without an off-chip transceiver. There's a reason why most low-cost microcontrollers are USBFS only.
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