Megasquirt III Prototype
#24
Former Vendor
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For many, yeah, it's just unnecessary, but you can always just ignore the top few rows/columns if the dyno clock is ticking a bit quickly.
#26
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For one, the USB port on the MS3 is a type B receptacle, typically found on client devices (DCE, for you old-timers) such as printers. Such devices typically are incapable of acting as hosts to other peripheral equipment, but only as clients to a host (ie, a PC.) Additionally, my suspicion is that this particular USB device is simply a virtualized RS232 connection. There was talk of implementing it that way at several points in the discussion, and doing so would have reduced its burden on the CPU to almost zero, whereas implementing the full-blown USB protocol in software would have chewed up considerable processor resources, which is not something you want to do in a mission-critical realtime system.
#27
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Additionally, my suspicion is that this particular USB device is simply a virtualized RS232 connection. There was talk of implementing it that way at several points in the discussion, and doing so would have reduced its burden on the CPU to almost zero, whereas implementing the full-blown USB protocol in software would have chewed up considerable processor resources, which is not something you want to do in a mission-critical realtime system.
#29
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Ok, that explains the physical size of the connector, which I was wondering about. In the past, I've used a device which was packaged as a slightly oversized USB-B connector and integrated the electronics into the package. You spoke to the device in standard RS-232, and it presented itself to the host as an RS-232 port. Saved a tiny bit of board space, as it was only one device instead of two.
I can't really tell from the pictures, are they using one of the FTDI "FT232" series transceivers? Most of those are QFPs, but the only square chip I see is the processor.
I can't really tell from the pictures, are they using one of the FTDI "FT232" series transceivers? Most of those are QFPs, but the only square chip I see is the processor.
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