mesa 7i33 7i37

which is the enable except step and dir ?

Not sure I understand...
 

For example pwmgen module except dir and pwm has enable pin
IOPortTag & x"00" & PWMTag & x"81", -- pwm
IOPortTag & x"00" & PWMTag & x"82", -- dir
IOPortTag & x"00" & PWMTag & x"83", -- pwm enable

stepgen has dir step and which is enable ?

There is no (hardware pin) enable for step/dir since its always driven

7i37 has 16 in 8 out and it is parallel
7i84 has 32 in and 16 out and it is sserial
Have any other difference ?

Can use 7i84 instead of 7i37 for home-limit switches probe-in estop-in and general I/O
like tool-clamp-out tool-sensor-in ?

Basically they are interchangeable.

The 7I37 Inputs and outputs are a bit more flexible
(they can both sink and source since they are all isolated)
This means more wiring however since there is no common

The 7I84 has only sourcing outputs and sinking inputs

With 7i37TA i have tried inputs for home-limit switches and when the switches triggered became TRUE in hal the inverted input (in_not)
This hal config worked with 7i80hd + 7i37TA
net estop-ext <= hm2_7i80.0.gpio.024.in_not
net home-x <= hm2_7i80.0.gpio.026.in_not
net both-x <= hm2_7i80.0.gpio.029.in_not
I have common ground for outputs to all peripherals and driving voltage is 28-29V (<1A current example electrovalves/mini relays) so sourcing outputs is that i want plus double I/O with 7i84..

Which are the names to access from hal the pins of 7i84 connected to 7i80hd ?
hm2_7i80.0.7i84.0.0.output-00
hm2_7i80.0.7i84.0.0.output-00-invert
hm2_7i80.0.7i84.0.0.input-00
hm2_7i80.0.7i84.0.0.input-00-not