Date: Wed, 13 Nov 2019 22:31:42 +0100 From: Bernd Walter <ticso@cicely7.cicely.de> To: Ian Lepore <ian@freebsd.org> Cc: ticso@cicely.de, John-Mark Gurney <jmg@funkthat.com>, freebsd-arm@freebsd.org Subject: Re: Choose between Raspberry Pi 4B 4GB and ROCKPro64 Message-ID: <20191113213142.GY43404@cicely7.cicely.de> In-Reply-To: <0ad483794f3f1163a852025f4aa331efde82fb7d.camel@freebsd.org> References: <7b75e2ed23e334878fbb3c1d585ffc51.squirrel@10.1.1.11> <20191015220433.GS96402@funkthat.com> <20191112124539.GM43404@cicely7.cicely.de> <1573571378957-0.post@n6.nabble.com> <20191112221610.GN43404@cicely7.cicely.de> <20191112225251.GB4552@funkthat.com> <20191113075343.GP43404@cicely7.cicely.de> <20191113164800.GS43404@cicely7.cicely.de> <0ad483794f3f1163a852025f4aa331efde82fb7d.camel@freebsd.org>
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On Wed, Nov 13, 2019 at 01:42:13PM -0700, Ian Lepore wrote: > On Wed, 2019-11-13 at 17:48 +0100, Bernd Walter wrote: > > I just remembered that I own an FTDI FT4232H module. > > This one is capable of 12Mbps with 2k Buffers and high speed USB. > > I have it at a different location - guess I will have to drive and > > pick it up. > > You'll certainly have no trouble with the ftdi 4232. I've tested those > at 6mpbs in both directions concurrently without any data loss. > > IMO, breaking free of the 115200 barrier is long overdue, but it would > have been nice if the step up everyone took was to 921600, because > virtually all usb-serial support that. With line-level rather than > ttl-level adapters, 1mpbs is often the effective speed limit because of > the cheap rs232 line-level chips they use. I don't think many USB uarts are capable to divide 48MHz into 921600 * oversampling without being off too much. The high speed ones are a different beast, since they likely have a PLL and run with an internal 480MHz clock. -- B.Walter <bernd@bwct.de> http://www.bwct.de Modbus/TCP Ethernet I/O Baugruppen, ARM basierte FreeBSD Rechner uvm.
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