[Linux-parport] Parport signals stability with SiS chipset
Eric BENARD / Free
ebenard at free.fr
Mon Feb 9 11:24:49 GMT 2004
I'm trying to get a small jtag software to run under Linux and I meet problems
with the parallel port :
- on two PC (a Dell Intel based Notebook and an Asus VIA/AMD based),
everything is ok, I can write and read correct data to the board (an ARM7
- on the other PC (Asus Pundit with SiS651/962 chipset & Celeron4 CPU), the
parport IO are always swinging so data gets corrupted.
Both PC have the same settings (SPP). I tried with 2.4.23 & 2.6.1 & 2.6.2
kernels on the Asus without any success.
I quickly tested on a SiS630 PC and I have the same problems than on the
Pundit, so this could come from a problem with the SiS chipset handling
Of course, I checked that no other software was trying to use the parport. I
unloaded lp, and only ppdev is loaded.
The problem is the same if I try to access the parport directly (io @ 0x378)
or through ppdev (/dev/parport0).
Here is the schematic used for the JTAG adapter :
Do you have an idea of what could be wrong ? Or maybe where I should look to
get more details and solve this problem ?
Many thanks for your help & best regards
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