New project, litehm2: a hostmot2 port to linsn rv901t

Yes, see github.com/litex-hub/litex-boards/pull/506 . Don't add JP4, i do that in hostmot2.py.

sensille wrote:

IlyaKw wrote:

In case of RV901T you should cut one trace in two places then solder it to GND and add a smd 0805 1k resistor to 3V3. In the end you will get U603, U607, U602, U606 as input and U605, U601, U604, U600 as output ports.


Do you by any chance have more information on where to cut it? A pic, or a link?

If you wouldn't mind to post this info here then  tomorrow I will do this with pics and an explanation.

RV901T Modification
There are two options. 
The first one consists of:
1. removing of R608 resistor (upper part of the board)
2. cutting the track which goes to FPGA F13 pin,
3. solder the resistor (0805 1K) that will pull up to 5V upper segment of the track
4. cutting the track  (bottom right corner)
5. connecting its bottom part to GND polygon

The second one consist of:
1. cutting the track (bottom right corner)
2. connecting its bottom part to GND polygon
3. in FPGA "connect" F13 pin to Vcc

All of these options work.

 
 

I hope I was able to explain the point
Regarding the supply voltage of the 245 buffers. Currently I have two boards that works with no modification of supply voltage. It is 5V (4.89 in fact). Of course it does not meet the requirements DC characteristics of Spartan6 but it works.I can't tell how long this will last.
It would be safer to power them from a lower voltage. One easy way to add a  silicon diode to the +5V that supply the board.

Seems very clear on what to remove, cut, add, and solder.
Thank you.

Thanks for the clear instructions. I will link to this post from the README, if that's okay.

Regarding the 5V-issue ... It looks like the Spartan 6 has no clamp diodes on the inputs. This is the reason why it does not immediately break down. So we might get away with this as long as the drivers are only powered when the spartan is also powered.

@sensille
I found there is exactly 72 pins.
If declared more, some lost. If declared less, got LinuxCNC error.
I found code below, but not understand it.
3*24=72, there are no other 72 string anywhere else in the code.
This match, but I don't know, can I change these values?