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Forum Index : Microcontroller and PC projects : PicoMite 2 HDMI USB I2S board....
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Grogster Admin Group  Joined: 31/12/2012 Location: New ZealandPosts: 9805 |
Very sexy!    Easy to setup, cheaper to produce then the CMM2G2v2(with no disrespect), and lovely feature-set. I've only now had a chance to play with these, as up until now, I have been busy with work. But now I am on my Christmas holiday, I can spend a bit of time, tinkering with things like this. I have not yet tried out everything, but I must spew forth, my absoulute LOVE of the included audio DAC chip. This is BRILLIANT, when hooked up to a good amplifier. Again, no disrespect to the wonderful LPF on the CMM2 etc - Volhort did brilliant work there, but the fact is, that a dedicated DAC will always be better then PWM + LPF. Four-port USB hub is an excellent idea, and with the HDMI video, this thing is just about perfect. The only complaints you will get now, are those moaning that the audio is not on the HDMI port.....because people are never happy.  Smoke makes things work. When the smoke gets out, it stops! |
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elk1984 Senior Member  Joined: 11/07/2020 Location: United KingdomPosts: 230 |
Very nice. Are these available premade in the UK (or as a shared project on the PCB manufacturer sites)? |
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Mixtel90 Guru  Joined: 05/10/2019 Location: United KingdomPosts: 8401 |
It's one of matherp's. Linkey here. Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| ville56 Guru Joined: 08/06/2022 Location: AustriaPosts: 366 |
found this on Amazon ... maybe this could solve the issue HDMI audio inserter 73 de OE1HGA, Gerald |
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| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9805 |
MP3 playback is SLOW, and interrupted with pops and clicks. WAV is fine. WHAT MP3 FILE COMPRESSION PROTOCOLS(bitrates etc) ARE SUPPORTED BY THE DAC/MMBASIC on the 2350B CHIP? I am working on making a sample video so I can post it here. Perhaps some bitrates are NOT supported? Smoke makes things work. When the smoke gets out, it stops! |
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| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9805 |
It seems......... Smoke makes things work. When the smoke gets out, it stops! |
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| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9805 |
......not all SD cards are equal. Copied the MP3 files to another SD card, and they are ALMOST perfect. First card was a 128MB(yes, MB) uSD card for experimentation, formatted as FAT32. Copy rate was about 2.6MB per second, so I thought it would have no trouble reading MP3 data. Seems not. Next test was 8GB ADATA, also formatted as FAT32. No pops or clicks on playback with this one, but still the OCCASIONAL skip, in the order of about 200ms or so of skipped audio output. IS THERE A RECCOMENDED MINIMUM SD CARD SIZE AND SPEED for use with this unit? As I say, WAV playback is FLAWLESS(even from these same cards), but mp3 is a bit "Jittery" at times. With the size of SD cards these days, there is no reason to NOT use full uncompressed WAV files, I guess!  Smoke makes things work. When the smoke gets out, it stops! |
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phil99 Guru Joined: 11/02/2018 Location: AustraliaPosts: 2891 |
Try a high CPU speed. Decompressing MP3s requires a lot of processing. Doing it in real time may need more speed. Edited 2025-12-30 17:30 by phil99 |
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| dddns Guru Joined: 20/09/2024 Location: GermanyPosts: 720 |
I own two PGA2350(A2) and experienced the same as well as other errors with devices connected to GPs higher than GP29. Especially with SD cards. If you have a spare SDcard interface try to set it up on the external I/O using some GPs in the range 0 - 7 I tested several MP3s encoded with 192Kbit and they play and sound good without any clicks or delays |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 8401 |
If SD cards are set up on ordinary GP pins with all pins specified they are bit-banged IIRC. If you put them on SYSTEM SPI and only configure the CS pin they run on hardware SPI, which is faster and more efficient. This may well make a difference when accessing mp3 files from them. I don't know this particular board, but I assume that Peter will have used hardware SPI for the SD card. . Edited 2025-12-30 19:29 by Mixtel90 Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| Grogster Admin Group Joined: 31/12/2012 Location: New ZealandPosts: 9805 |
I'm just using the default setup, which is 640 x 480 @ 252MHz. I would have thought that 252MHz was PLENTY fast enough for decoding MP3 data. It would not be the first time I was wrong, though, if that is not actually the case! I'm going to try some more files tonight, but just changing to the 8GB uSD card, made a big improvement. Smoke makes things work. When the smoke gets out, it stops! |
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