Matheo Jr
2014-08-11 12:02:31 UTC
hello everyone
I need help with writing jtag hardware description file. i'm not skilled yet.
I'm playing with ppc ibm 403gcx equipped board. bsdl file isn't available.
however got pinout from manufacturer pdf, and after some playing with urjtag +
simple logic analyzer I managed to pinpoint all needed data register bits for
manipulationg flash with EXTEST command. banging from pregenerated script let
me read whole flash contents. however, I really prefer to program memory with
urjtag offered commands and hopefully prototype bus. I came across some problem
while reconstructing urjtag hardware description file. I noticed that data
register bits corresponding to data/address are organized different after
shifting out than when shifting in. 'dr' readout bitstream is shifted by one
bit number compared with bit places (data/addr) when shifting data register
contents in. for example bits to setup data bus (flash organized 512k x 8)
occupy 21-30 bsr bits (with 2 bits gap inside), while data bus readout bits are
reflected on 22-31 bsr bitstream.
how to describe function of 22 dr bit then? cpu data line is of I/O type ofc.
shifted out bit 22 reflects state of D7 (data bus 7-th line), while that same
bsr bit at shifting-in is devoted to setup D6 data line. I know of control
cells, and probably found a few, but all examples/explanations i found show
that bidirs are composed of 3 cells. where data seen on input pin is latched by
some cell & presented on 'n' bsr bit, data to setup that pin state, when at
output,must be shifted in on n+1 position (or another neighbour position) to set
another cell. and one another control cell that controls direction /
hi-impedance state of one/group of 'pins'. no pin representing bits are
overlapped in respect to this idea.
in my case something is overlapping :(
what to do with this? is writing a dedicated bus type to overcome this probl. is
really needed? please help with people with this.
BR, Matheo
I apologize for posting in html before.
_____________________________________________________________
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I need help with writing jtag hardware description file. i'm not skilled yet.
I'm playing with ppc ibm 403gcx equipped board. bsdl file isn't available.
however got pinout from manufacturer pdf, and after some playing with urjtag +
simple logic analyzer I managed to pinpoint all needed data register bits for
manipulationg flash with EXTEST command. banging from pregenerated script let
me read whole flash contents. however, I really prefer to program memory with
urjtag offered commands and hopefully prototype bus. I came across some problem
while reconstructing urjtag hardware description file. I noticed that data
register bits corresponding to data/address are organized different after
shifting out than when shifting in. 'dr' readout bitstream is shifted by one
bit number compared with bit places (data/addr) when shifting data register
contents in. for example bits to setup data bus (flash organized 512k x 8)
occupy 21-30 bsr bits (with 2 bits gap inside), while data bus readout bits are
reflected on 22-31 bsr bitstream.
how to describe function of 22 dr bit then? cpu data line is of I/O type ofc.
shifted out bit 22 reflects state of D7 (data bus 7-th line), while that same
bsr bit at shifting-in is devoted to setup D6 data line. I know of control
cells, and probably found a few, but all examples/explanations i found show
that bidirs are composed of 3 cells. where data seen on input pin is latched by
some cell & presented on 'n' bsr bit, data to setup that pin state, when at
output,must be shifted in on n+1 position (or another neighbour position) to set
another cell. and one another control cell that controls direction /
hi-impedance state of one/group of 'pins'. no pin representing bits are
overlapped in respect to this idea.
in my case something is overlapping :(
what to do with this? is writing a dedicated bus type to overcome this probl. is
really needed? please help with people with this.
BR, Matheo
I apologize for posting in html before.
_____________________________________________________________
Join the fastest growing e-mail service in the Pilippines. It's Free. It's cool. Go to http://www.e-mail.ph and Sign up now.