7i95 sserial port as gpio

 I'm using the Mesa 7i95t, and I just need a few simple output pins. So, I wanted to disable the smart serial port to gain those pins as GPIO.

In my hal file, I have...

loadrt [HM2](DRIVER) board_ip=[HM2](ADDRESS) config="num_encoders=6 num_stepgens=6 sserial_port_0=xxxxxxxx"

However, at start up I get errors...HAL: ERROR: pin_new(hm2_7i95.0.stepgen.00.counts) called with already-initialized memory
HAL: ERROR: pin_new(hm2_7i95.0.stepgen.00.velocity-fb) called with already-initialized memory

Why does unloading the sserial module cause stepgen errors?

Also, where do I find the .pin file mentioned by members of the forum - where the gpio pin numbering lives.

Note: if I change the last "x" to "0", like this ....
loadrt [HM2](DRIVER) board_ip=[HM2](ADDRESS) config="num_encoders=6 num_stepgens=6 sserial_port_0=xxxxxxx0"
Then the errors go away.

Thanks all.p, li { white-space: pre-wrap; }

  

OK smart serial if it detects no devices it reverts to gpio.

To work out the pins v gpio
mesaflash --device 7I95T --addr <ip address of card> --readhimd

Warning:
Just beware that you will gain 1 Input & 1 output due to the RS422 chip on board, ie they wont be the same as a normal GPIO pin. I'd wait for Pete from Mesa to chime in regrading voltage levels, current draw and whether this is a good idea.

Yes, you will only gain 1 differential input and 1 differential output

Why does unloading the sserial module cause stepgen errors?

Probably a driver bug and the 0 enabled sserial channels string
corner condition that causes a memory allocation error was missed.

The xxxxxx0 string will accomplish the same thing without triggering the error
The pins will always revert to GPIO if no sserial device is found, but
the advantage of the xxxxxx0 string is disabling the initial sserial device probe.

If you need TTL level inputs, spare encoder pins can be used
 
Is P1 being used? that gives you 17 GPIO pins if available.

No, P1 is not used. I don't see a config modparam to disable P1 in the man pages. So, does that mean if by virtue of P1 not connected it is disabled and I can use the GPIO pins. I'd rather use P1 because it seem sserial is more problematic.

Can you tell me how exactly to use P1 pins for GPIO? Thanks.

I need 5V outputs. I'll drive some low power relays using these GPIO's.

With standard firmware P1 is all GPIO regardless of driver settings

man hostmot2

For GPIO setup information

(GPIO starts up as inputs so pins used for outputs
must be set into output mode)

Note that the P1 pins are 5V tolerant but have 3.3V output levels
Suggest using a cheap parallel port breakout if you want buffered 5V levels

I decided to go with a buffered parallel port BOB to get more GPIO (Mesa 7i75 Breakout/FPGA protection card). But I also need a pwmgen to drive a Mesa SPINx1A for the VFD. I plans to use all 6 step/direction and encoder channels eventually, so I don't want to use one of those for VFD speed control if I don't have to. Leaving the sserial as is for future expansion.

So I need firmware which adds 1 pwngen to the P1.

Would 7i95t_5abobd.bin in the MesaCT do this? I assume it would make 5 pwmgen's available; and for those pins I want to use as I/O, I just declare them in HAL as GPIO. Is this correct?

Or do I need special firmware?

7i95t_5abobd.bin has 1 PWMgen and I think 4 or  or 5 additional stepgen channels

Its designed for the common "Sainsmart Mach 5 Axis breakout"
 

Do I need special firmware? Can you please make one for me?

No, 7i95t_5abobd.bin should work.