Conversation
takaswie

Takashi Sakamoto (坂本 貴史)

Edited 11 days ago
He found the way to operate with BeBoB console for M-Audio FW 1814, surprising!

https://bsky.app/profile/mrmidi.bsky.social/post/3mtc23zcaj222
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takaswie

Takashi Sakamoto (坂本 貴史)

Reply to @takaswie
I think @wagi can provide helpful information about it, don't you?
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wagi@mastodon.social

LostConnection

Reply to @takaswie

@takaswie uhh it's been a while. :)

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wagi@mastodon.social

LostConnection

Reply to @wagi@mastodon.social

@takaswie ah this was a workaround because the switch matrix had a serious bug. The serial console was not usable after changing the clocks. Thus some interesting workaround were added to get serial console access.

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takaswie

Takashi Sakamoto (坂本 貴史)

Reply to @wagi@mastodon.social
@wagi Ah, a workaround. Does the switch matrix problem seem to be circuit level? If so, it is surprising that any change of clock for audio signal processing (or packet processing) affects the baud rate in UART...
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wagi@mastodon.social

LostConnection

Reply to @takaswie

@takaswie

Yes, the dm1000 pin multiplexer in hardware has this sever bug. As soon the clocks are set the TX/RX pins are gone forever (*). Not slow or so, gone.

We implemented various interesting workarounds to get the serial console out of the dm1000 after switching the clocks.

This was almost the end of the company at this point, because there was no money for fixing the mask.

(*) if you don't set the clocks, the ARM CPU runs with a couple of kHz.

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wagi@mastodon.social

LostConnection

Reply to @wagi@mastodon.social

@takaswie

IIRC, a few years later, after we had the new chip generation (dm1200), the dm1000 mask was fixed and we got native serial console. Though it was a bit too late, no one cared.

We (engineering) estimated we spend propably more money in the work around than the mask fix would have been.

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takaswie

Takashi Sakamoto (坂本 貴史)

Reply to @wagi@mastodon.social
@wagi Oh, gone, additionally forever... That's a sort of bad dream for embedded engineers. I've opened so many boxes, but never seen DM1200, in my memory, as you said.

I can agree that the cost of software engineering is often underscoped... But the console via async transaction is enough interesting to me. I attempt to make my implementation, but in my opinion it looks one of bootloader functions. But is it available after the device starts running with its main firmware loaded by the bootloader?
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wagi@mastodon.social

LostConnection

Reply to @takaswie

@takaswie

The second generation chip was called 'Chekov' (Star Trek) and was available under different product names. IIRC, dm1500 was mostly for the FireWire products and dm12xx was for kitchen radio style products.

I can't remember those details. Sorry, it's been a while.

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takaswie

Takashi Sakamoto (坂本 貴史)

Reply to @wagi@mastodon.social
@wagi Actually I can see that some USB/FireWire hybrid products use ArchWave DM1500 (e.g. Behringer FCA610). I wish I would find such a product with DM1200 someday, but it already takes two decades since the ASIC was shipped. It seems to be hard, sigh...

By the way, I have a question about DM1000 configuration ROM. I can see some products have dependent info directory, containing two offsets. For example, this is an example of M-Audio FireWire Solo:

dependent info directory at 1104
-----------------------------------------------------------------
1104 000637c7 directory_length 6, crc 14279
1108 120007f5 specifier id
1112 13000001 version
1116 3affffc7 (immediate value)
1120 3b100000 (immediate value)
1124 3cffffc7 (immediate value)
1128 3d600000 (immediate value)

If you have any idea about what were 0xffffc73b100000 and 0xffffc73d600000, it really helps my interests.
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