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#rp2350

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Stylus

I have pico-mac playing the system beep on an i2s dac (though when @adafruit @ladyada made a build locally, it didn't work for her, hmmmm, I'll get that sorted tomorrow)

in the process, I discovered an interesting problem that might be randomly corrputing a certain 740 bytes of RAM when pico-mac or umac is configured for a non-power-of-two memory size! github.com/evansm7/umac/issues

the fix seems to be another rom patch:

        /* Fix up the sound buffer as used by BootBeep */
        ROM_WR32(0x292, RAM_SIZE - 768);

and is also included in github.com/evansm7/umac/pull/14

you also avoid the problem if you configure pico-mac for 256kB, 512kB, 1024kB, etc.

GitHubSystemBeep splats memory on memory sizes like 208k · Issue #15 · evansm7/umacBy jepler
#marchintosh#picoMac#umac
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Stylus

I contributed a patch to umac to allow bigger resolutions. How about 1280x720? I even learned a tiny bit of 68k assembly in the process.

It was a bit tricky, as there were places that the screen width in bytes is used as an 8-bit signed constant. For 1024 pixels and up, the immediate value became 0x80, which is -128, not 128... out-of-line patches were needed in order to have 16-bit constants in the mouse cursor draw & hide routines.

github.com/evansm7/umac/pull/12

my hope, which is quite distant, is to support this resolution on rp2350 with hstx (since I've previously seen it make an excellent 1280x720 text mode with dvhstx)

A black&white screenshot of a classic Macintosh desktop running at 1280x720 pixels resolution. the control panel is shown.
#marchintosh#rp2350#umac
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Phil M0OFX

Great talk by Aedan Cullen at #38c3 on breaking security on the #RP2350 by glitching the OTP VDD.

streaming.media.ccc.de/38c3/re

I expect the bus between the state machine and OTP is like Wishbone or M68K and has a request and an acknowledge, and the data is latched on the ACK. No ACK? Guard word stays in the latch.

streaming.media.ccc.deRelive: Hacking the RP2350 – 38C3: Illegal Instructions StreamingLive streaming from the 38th Chaos Communication Congress
#ICRE#ICReverseEngineering#FaultInjection
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AlgoCompSynth by znmeb 🇺🇦

@kkarhan @jemo07 Speaking of #Forth boot firmware, Mitch Bradley's cforth, descended from the boot firmware for Sun workstations and One Laptop Per Child laptops, is here:

github.com/MitchBradley/cforth.

I have it running on one of them new-fangled #RP2350 boards.

GitHubGitHub - MitchBradley/cforth: Mitch Bradley's CForth implementationMitch Bradley's CForth implementation. Contribute to MitchBradley/cforth development by creating an account on GitHub.
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