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JTAG port on MPC850 based router

Started by Clint Sharp November 14, 2004
Hi All, I have a router that has had a flash ROM problem, to the extent 
that it gets stuck before it properly initialises (proven by ROM 
substitution) to a point where I can replace the corrupt contents. The 
router is MPC850 based and has a JTAG port on the board, can I use this 
port/BDM mode to read out a good ROM and re-flash the corrupted ROM? If 
not, can you point me in the direction of a DIY programmer that will 
handle Sharp LH28F016 chips?
-- 
Clint Sharp
Clint Sharp <clint@clintsmc.demon.co.uk> wrote in 
news:idV+vEEho9lBFwDe@clintsmc.demon.co.uk:

> Hi All, I have a router that has had a flash ROM problem, to the extent > that it gets stuck before it properly initialises (proven by ROM > substitution) to a point where I can replace the corrupt contents. The > router is MPC850 based and has a JTAG port on the board, can I use this > port/BDM mode to read out a good ROM and re-flash the corrupted ROM? If > not, can you point me in the direction of a DIY programmer that will > handle Sharp LH28F016 chips?
Last time I check the MPC850 has BDM not JTAG. PE Micro make a PPC BDM device that should do the job. You need to check about the flash chips to be sure. Allan
In message <to5md.3019151$yk.469793@news.easynews.com>, Allan R. 
Batteiger <arb@rtsi.com> writes
>Last time I check the MPC850 has BDM not JTAG. PE Micro make a PPC BDM >device that should do the job. You need to check about the flash chips to >be sure.
Yep. Doesn't support my flash.
> >Allan
So, I've misread this PDF? http://www.freescale.com/files/netcomm/doc/app_note/AN2387.pdf Or is it inaccurate? I'm new to JTAG but remember BDM from earlier chips... From what I can gather, I can either use a 'wiggler' type device (if it is JTAG compliant) and use the target device I/O pins to pretend to be a programmer or download a boot loader to the device and load the code via a serial port... neither of which seems attractive as all the devices that support my CPU are way more expensive than the router I want to re-flash. There are a couple of freeware offerings that look promising but it would be really nice if someone could give me a heads-up or point me at something they know to work. Basically, the router is an Efficient networks 5861 DSL device with an XPC850 chip and a Sharp LH28F016 flash -- Clint Sharp
Clint Sharp <clint@clintsmc.demon.co.uk> wrote in news:xyoK07HZESmBFwq5
@clintsmc.demon.co.uk:

> http://www.freescale.com/files/netcomm/doc/app_note/AN2387.pdf
Clint From what I can tell the only interface anyone has to program flash or control the chip is BDM. The spec may indicate JTAG, but the jtag may be limited functionality, or no one has developed any software to use it instead of the BDM. The two units I have used are Macraigor and PE Micro both work using BDM. Allan
Clint Sharp wrote:
> Hi All, I have a router that has had a flash ROM problem, to the extent > that it gets stuck before it properly initialises (proven by ROM > substitution) to a point where I can replace the corrupt contents. The > router is MPC850 based and has a JTAG port on the board, can I use this > port/BDM mode to read out a good ROM and re-flash the corrupted ROM? If > not, can you point me in the direction of a DIY programmer that will > handle Sharp LH28F016 chips?
Hi, Our Chameleon POD (a reconfigurable dongle) can works as Macraigor Raven Emulator, as Macraigor Wiggler, as P&E Micro BDM interface. In fact we are able to clone all the popular BDM & JTAG interface emulators working on the parallel port. Also, you will be able to do your own custom EPP/ECP application, since Amontec gives all documentation of the POD, including schematic and VHDL examples. You just have to buy Chameleon POD, all pre-configurations are coming for FREE with our Chameleon POD Programmer tool. It should be a nice solution for you. For more info, please goto www.amontec.com Kind regards, Laurent Gauch