**** BEGIN LOGGING AT Tue Dec 31 02:59:58 2013
Dec 31 09:21:51 <ayaka> I have brought a ft2232 core board(similar to DS_FT2232H_Mini_Module
Dec 31 09:21:51 <ayaka> )
Dec 31 09:22:45 <ayaka> but how to use it as jtag to my board, is there external electric need?
Dec 31 11:08:11 <PaulFertser> ayaka: hi :) So you went the hard way, that's ok.
Dec 31 11:08:18 <PaulFertser> ayaka: I can explain you how to wire it.
Dec 31 11:08:35 <ayaka> PaulFertser, please
Dec 31 11:08:35 <PaulFertser> ayaka: first thing, download the ft2232h datasheet.
Dec 31 11:08:43 <ayaka> I have downloaded
Dec 31 11:08:45 <PaulFertser> ayaka: there you'll see MPSSE pin assignments for jtag.
Dec 31 11:08:58 <PaulFertser> Wire TMS, TDO, TCK, TDI according to it.
Dec 31 11:09:07 <PaulFertser> ayaka: TRST signal is optional, you can omit it.
Dec 31 11:09:37 <ayaka> PaulFertser, please wait a moment, you don't any externel electronic component?
Dec 31 11:09:39 <PaulFertser> ayaka: SRST is optional too, you can usually press a push-button on your target board or physically power-cycle instead of using srst, so for the first try it's ok to omit it.
Dec 31 11:09:55 <ayaka> I am in the lab this time, it is easy to get some
Dec 31 11:10:24 <PaulFertser> ayaka: but one thing is important: to get proper JTAG connectivity you're likely to need series resistors on every line (except GND). I recommend 47 Ohm or something about that.
Dec 31 11:10:51 <ayaka> ok
Dec 31 11:10:58 <PaulFertser> ayaka: you can try without them too, and probably it'll work for some targets but probably will fail with other targets. So series resistors are highly recommended. They're needed to reduce "ringing".
Dec 31 11:11:19 <PaulFertser> ayaka: and you should power the Vccio (output buffer) of your ftdi chip from the target itself.
Dec 31 11:12:12 <PaulFertser> ayaka: that's about it, you should get a nice enough jtag adapter. Then just get openocd, compile with --enable-ftdi, use e.g. interface/ftdi/jtagkey2.cfg (with default reset_config none, i.e. do not set reset_config anywhere at all).
Dec 31 11:13:10 <ayaka> PaulFertser, is that all?
Dec 31 11:13:59 <PaulFertser> ayaka: yes. Optionally connect the second UART port of the ftdi chip to the target's UART (Tx-Rx, Rx-Tx) and use minicom (or any other terminal emulator) to communicate with the target.
Dec 31 11:14:46 <ayaka> PaulFertser,  I see thank you, the symbols of SoC is a little different
Dec 31 11:15:23 <PaulFertser> ayaka: some targets do require TRST so after testing everything works you can additionally add an appropriate connection (any free GPIO on ftdi will fit). If you need SRST I recommend connecting additional transistor to make the output open-drain/open-collector.
Dec 31 11:16:35 <PaulFertser> ayaka: if you decide to add trst and/or srst I recommend choosing one of the configs in the ftdi subdirectory that corresponds to a device with available schematics (preferrably free hardware one) and use it as a reference to avoid writing your own config.
Dec 31 11:17:37 <PaulFertser> ayaka: you'll also be able to reflash SPI NOR Flash memories with your adapter thanks to flashrom project, you do not need to give any additional thought to it.
Dec 31 11:18:11 <PaulFertser> ayaka: when I say trst I mean JTAG Reset pin, when I say SRST I mean "system reset" i.e. the pin that resets the whole SoC.
Dec 31 11:19:31 <ayaka> PaulFertser, http://imagebin.org/284584
Dec 31 11:20:30 <ayaka> PaulFertser, the picture is the schemic of the SoC core board, there is only TRST 
Dec 31 11:25:19 <PaulFertser> ayaka: nreset is what i call srst
Dec 31 11:25:44 <PaulFertser> ayaka: here they connect it together with trst, I think that's stupid and useless.
Dec 31 11:26:26 <PaulFertser> trst is test logic reset. Either connect it to a dedicated adapter pin or do not connect at all, the jtag standard allows to reset test logic without trst easily.
Dec 31 11:30:19 <ayaka> PaulFertser, I see thank you so much
Dec 31 11:30:28 <PaulFertser> ayaka: welcome
Dec 31 11:30:37 <ayaka> I will let one of my friend to connect them
Dec 31 11:31:12 <ayaka> in the SoC core board, there are just some little spot welds
Dec 31 11:31:56 <PaulFertser> Testpoints
Dec 31 11:32:16 <PaulFertser> Or "pads"
Dec 31 11:37:04 <ayaka> I don't know its english, I just use my dictionary to find out that word
Dec 31 11:38:45 <PaulFertser> ayaka: I hope you do not mind me telling you the right word ;)
Dec 31 11:42:32 <ayaka> PaulFertser, of course not, I shall thank you, you are so kind to pick up my mistake
Dec 31 11:47:14 <PaulFertser> ayaka: :)
Dec 31 11:59:35 <ayaka> before I have ft2232, I always use ch341a to programmer SPI nor flash
Dec 31 11:59:48 <ayaka> it is really a slow chip
**** ENDING LOGGING AT Wed Jan 01 02:59:58 2014