I created a small tutorial about JTAG. See http://www.fpga4fun.com/JTAG.html I'd be happy to hear about mistakes/suggestions. Thanks.
JTAG tutorial
Started by ●May 12, 2006
Reply by ●May 12, 20062006-05-12
>I created a small tutorial about JTAG...http://www.fpga4fun.com/JTAG.html> >...happy to hear about mistakes/suggestions...I haven't read it in detail, so I won't comment on the content, but I like the style. It's well-paced. It's concise. It doesn't have unnecessary and confusing repetition. It's laid out clearly with good diagrams. Most articles fail on all these points. I'd only say that it's best to avoid writing small numbers (1-10) and non-exact numbers as digits. E.g. it's easier to read "a few thousand...three inputs and one output" than "a few 1000...3 inputs, and 1 output". Mike
Reply by ●May 12, 20062006-05-12
On a sunny day (Fri, 12 May 2006 04:08:46 GMT) it happened "Jean Nicolle" <jean.nicolle@sbcglobal.net> wrote in <iTT8g.69949$_S7.49845@newssvr14.news.prodigy.com>:>I created a small tutorial about JTAG. >See http://www.fpga4fun.com/JTAG.htmlVery nice! Just learned a bit more about JTAG.
Reply by ●May 12, 20062006-05-12
Jean Nicolle wrote:> I created a small tutorial about JTAG. > See http://www.fpga4fun.com/JTAG.html > > I'd be happy to hear about mistakes/suggestions. > Thanks. > >You mentioned that some external Flash manufacuturers make versions that can be ISP via JTAG? I have been looking for such a Chip! Do you know of any off hand? Most are programmed through the SPI or Parrallel interface, it woulds be nice to have some JTAG capable for faster debug. Thanks, ELi
Reply by ●May 12, 20062006-05-12
Eli most flash devices do not have a JTAG port but can still be programmed via JTAG by ensuring all the pins of the flash chip which are required address, data, and control signals are connected to a device which does have a boundary scan port. Unused fpag pins are good for this. The JTAG software can then control the FPGA pins connected to the flash to write data into the flash device. If you are going to do it this way it is often necessary to take the WE pin to a spare pin on the JTAG header to enable the speed of the programming to be quicker. hope this helps Ad
Reply by ●May 12, 20062006-05-12
Thanks! Ok, I fixed a few instances of the numbers. <MikeShepherd564@btinternet.com> wrote in message news:eud862pue2p4m6u274up9jj7qhp8si0ena@4ax.com...> >I created a small tutorial about JTAG... > http://www.fpga4fun.com/JTAG.html >> >>...happy to hear about mistakes/suggestions... > > I haven't read it in detail, so I won't comment on the content, but I > like the style. It's well-paced. It's concise. It doesn't have > unnecessary and confusing repetition. It's laid out clearly with good > diagrams. Most articles fail on all these points. > > I'd only say that it's best to avoid writing small numbers (1-10) and > non-exact numbers as digits. E.g. it's easier to read "a few > thousand...three inputs and one output" than "a few 1000...3 inputs, > and 1 output". > > Mike
Reply by ●May 12, 20062006-05-12
Correct. I actually know only one flash that can be programmed through JTAG (Platform flash, made by ST, sold by Xilinx). So I'm a little optimistic in my webpage. Anyone knows if we can get these flash from ST directly? or another source? "Ad" <adam.taylor@eads.com> wrote in message news:1147441764.754114.86100@d71g2000cwd.googlegroups.com...> Eli > > most flash devices do not have a JTAG port but can still be programmed > via JTAG by ensuring all the pins of the flash chip which are required > address, data, and control signals are connected to a device which does > have a boundary scan port. Unused fpag pins are good for this. The JTAG > software can then control the FPGA pins connected to the flash to write > data into the flash device. If you are going to do it this way it is > often necessary to take the WE pin to a spare pin on the JTAG header to > enable the speed of the programming to be quicker. > > hope this helps > > Ad >
Reply by ●May 15, 20062006-05-15
GREAT LINK. I typically check your website and have used your forums a few times. In fact I asked a question about the JTAG stuff a while ago. I have compiled and tried playing around with your examples with a 4 device board I designed. I am going to try writing my own C app to test my boards. Your site is just what I was looking for. Anyone know of other C tutorials for writing your own JTAG apps? I would rather write my own than buy the really expensive commercial applications. matt "Jean Nicolle" <jean.nicolle@sbcglobal.net> wrote in message news:Um59g.4988$fb2.2761@newssvr27.news.prodigy.net...> Correct. > > I actually know only one flash that can be programmed through JTAG > (Platform flash, made by ST, sold by Xilinx). So I'm a little optimistic > in my webpage. > Anyone knows if we can get these flash from ST directly? or another > source? > > "Ad" <adam.taylor@eads.com> wrote in message > news:1147441764.754114.86100@d71g2000cwd.googlegroups.com... >> Eli >> >> most flash devices do not have a JTAG port but can still be programmed >> via JTAG by ensuring all the pins of the flash chip which are required >> address, data, and control signals are connected to a device which does >> have a boundary scan port. Unused fpag pins are good for this. The JTAG >> software can then control the FPGA pins connected to the flash to write >> data into the flash device. If you are going to do it this way it is >> often necessary to take the WE pin to a spare pin on the JTAG header to >> enable the speed of the programming to be quicker. >> >> hope this helps >> >> Ad >> > >
