From mboxrd@z Thu Jan 1 00:00:00 1970 MIME-Version: 1.0 In-Reply-To: References: <94cf67bd0eeb9118a4ad5823ca4510fb@ladd.quanstro.net> Date: Tue, 26 Jul 2011 23:28:09 +0200 Message-ID: From: Gorka Guardiola To: Fans of the OS Plan 9 from Bell Labs <9fans@9fans.net> Content-Type: text/plain; charset=ISO-8859-1 Subject: Re: [9fans] jtag programmers Topicbox-Message-UUID: 072c2b12-ead7-11e9-9d60-3106f5b1d025 On Tue, Jul 26, 2011 at 11:25 PM, Gorka Guardiola wrote: > On Tue, Jul 26, 2011 at 9:46 PM, erik quanstrom wrote: >> can someone point me at a list of plan9 usb/serial compatable >> jtag programmers? >> > > As far as I know, ft2232 chips and their variants may work, but I have only > tried it with the Sheeva plug. > > The ft2232 serial chip inside the sheeva > can drive all sorts of serial things, including input to a jtag state machine > if connected properly. Inside the sheeva plug (and some other arm boards), > the chip is actually connected to the jtag input of the SOC inside it, > but you need > the concret details on how this is done for what you are using. > > What I do is I program (this is what usb/serial does) the interface connected to > the jtag for the right configuration to drive it. The device is also > programmable > and you need to program it (it is done so that the latency of the USB does not > kill you). Then you need to communicate with the other side, which includes > driving the reset bits (which depend on the concrete electronics connecting the > serial chip to the jtag interface) and then sending the right commands. All this is done outside usb/serial. Only a couple of parameters (latency and bit mode) are configured in usb/serial and a file is served. G.