**** BEGIN LOGGING AT Wed Jul 23 02:59:56 2008 Jul 23 19:56:09 Hi, what type of devices are discussed in here? Jul 23 19:56:47 I'm hoping someone can discuss JTAG on x86 devices Jul 23 19:57:41 ink_: although alot of x86 devices have jtag, it is very seldom used since most x86 devices have removable media Jul 23 19:57:55 i think quite a lot of people here use jtag for arm Jul 23 19:58:07 prpplague: it is possibly there's jtag for at-least boundary scan Jul 23 19:58:19 yes, I have noted that my AMD K6-2 device has JTAG Jul 23 19:58:24 bjdooks: yea, all of the geodes have jtag Jul 23 19:58:51 ink_: the real question is, "what do you wish to accomplish by using the JTAG interface?" Jul 23 19:58:52 But the flash chip is a tiny TSOP I'm not willing to remove Jul 23 19:59:20 And I sadly lost the serial connection I was using to update the flash image Jul 23 19:59:41 rendering it (a Cobalt Qube) quite useless Jul 23 20:00:52 I was going to build a Wiggler clone, but found one premade online for a little over a tenner Jul 23 20:01:39 yeah, there's plenty of them around Jul 23 20:01:58 it's a pity its such an old device, i cant find any datasheets for anything other than the AMD CPU and the AMD flash chip Jul 23 20:02:52 I was hoping i could find some specs for the southbridge (an Ali M1543). Jul 23 20:03:13 as i'm guessing i'll need to twiddle some pins on that to program the flash Jul 23 20:05:45 hmm, the m1543 is old Jul 23 20:06:16 The flash chip itself is an Am29F080B (JEDEC compatible if that helps) Jul 23 20:06:54 I'm guessing there is no support at all for an old CMOS chip like it in and of the open source JTAG projects Jul 23 20:07:50 But I imagine (?) that thats the least of my problems Jul 23 20:16:11 Should I expect to be able to identify a device (the CMOS flash chip) on the chain if I find I can get the K6-2's JTAG pins to respond at all ? Jul 23 20:18:11 I'm assuming I'll need to add a device definition file to allow it to be addressed at some later point Jul 23 20:24:17 ink: devices should respond to IDCODE Jul 23 20:34:33 ink_: you'll only be able to identify devices that are part of the chain - the Am29F080B doesn't have a JTAG interface, and thus wont be part of the JTAG chain Jul 23 20:35:25 ink_: what you need is knowledge of the JTAG boundary scan of a device that has a JTAG interface and connects to all the data, address and control pins of the flash chip Jul 23 20:36:21 ink_: flashing would then work by applying the necessary bit pattern to the flash pins via the output registers of the boundary scan chain Jul 23 20:38:59 ah, well as the southbridge chip seems to be the only nearby chip and i've no idea if it has jtag support, even worse i'd have little ot no chance of getting a bsdl? file for it which i believe i would definately need Jul 23 20:39:26 ink_: yeah, the bsdl file describes the boundary scan chain Jul 23 20:40:23 ink_: i've seen people claim that some x86s support debug via the jtag interface, which could help you, but there's absolutely no documentation available Jul 23 20:40:49 bugger is the word then. Ali (in Taiwan) say that NVidia now own the rights to the M1541/1543 chipset Jul 23 20:41:11 and they're notoriously unhelpful. Jul 23 20:42:08 are cobalt still around? Jul 23 20:42:19 no, Sun bought them. Jul 23 20:42:42 I spoke to a chap called Tim Hockin who worked on the BIOS development Jul 23 20:43:03 but he claims there were never schematics for the boards Jul 23 20:43:29 And always programmed the flash chips in system after careful testing. Jul 23 20:44:12 he thought the jtag headers (if any) were almost certainly unpopulated. Jul 23 20:45:34 I think I'm convincing myself that I'm going to have to replace the TSOP with a pre-programmed chip Jul 23 20:45:48 But I was rather hoping to tinker with JTAG if possible Jul 23 21:03:04 Well, anyone know of another cost effective way of writing to a 5v CMOS flash chip perhaps? Jul 23 22:23:14 i found the datasheets finally Jul 23 22:24:04 no jtag. only smbus and an xd-bus ? that appears to connect to the ROM **** ENDING LOGGING AT Thu Jul 24 02:59:56 2008