On Sunday 24 October 2021 14:11:09 Ralph Stirling wrote: > I'm interested in using the 7i90hd as an sserial remote, but am having > trouble pulling all the pieces together to build a configuration. I > will ultimately need four servo channels (encoder and pwm), three MPG > channels, and a bunch of discrete i/o. I may split this up into two > or three 7i90 ssremotes for the cleanest system organization, but one > sample config should give me enough information to make the others. > In addition to making the bitstream, I need to make a hal file, and > haven't seen quite enough documentation to do that either. > Unless Peter has been working overtime, the 7i90HD has two choices only of interface methods. 1. and the default is a direct connection to a parport, whose speed of update is not known to me as the pi's haven't a parport, but 2, there are firmwares you can load to it that are connected by a blaseing fast SPI bus, implemented on the rpi's in the rpspi.ko driver.
The SPI is setup as a transmission line, src terminated at the pi with 120 ohm grain of sand resistors, and in my case the cable from the pi to the 7i90HD is about an inch long. The pi sends the 7i90HD orders at about 41 megabaud, in 32 bit packets, and the 7i90HD sends the needed data back at 25 megabaud. Thats many times faster than the sseriel bus. Be aware too, that the i/o of the 7i90HD is connected directly to the fpga, and it takes very little noise going below ground or above the 3.3 volts the fpga runs on to blow a gate. So you'd best get a trio of the 7i42TA, and cables to mate them which will both give you the ultra convienient green terminal strips to wire it up with, while also protecting the 7i90HD from noise damage. I wasn't kidding about the speed, here is the initial sign on from starting LinuxCNC on my pi. pi@rpi4:/media/pi/workspace/vna-linux-tool $ linuxcnc -l LINUXCNC - 2.9.0-pre0-4838-gbe96bf6d6 Machine configuration directory is '/home/pi/linuxcnc/configs/sheldon-lathe' Machine configuration file is '7i90-axis.ini' Starting LinuxCNC... Found file(REL): ./hm2-7i90-stepper.hal Note: Using POSIX realtime hm2: loading Mesa HostMot2 driver version 0.15 hm2_rpspi: Platform: Raspberry Pi 4 Model B Rev 1.1 hm2_rpspi: Base address 0xfe000000 size 0x01800000 hm2_rpspi: Mapped peripherals from 0xfe000000 (size 0x01800000) to gpio:0x0xb4200000, spi:0x0xb4204000, aux:0x0xb4215000 hm2_rpspi: SPI0/CE0 clock rate: 41666000/25000000 Hz, VPU clock rate: 500000000 Hz hm2_rpspi: SPI0/CE0 write clock rate calculated: 41666666 Hz (clkdiv=12) hm2_rpspi: SPI0/CE0 read clock rate calculated: 25000000 Hz (clkdiv=20) hm2_rpspi: SPI0/CE0 Valid cookie matched hm2_rpspi: SPI0/CE0 Base: hm2_7i90.0 hm2/hm2_7i90.0: Low Level init 0.15 hm2/hm2_7i90.0: MD 2: 3x IOPort v0: accepted, using 3 hm2/hm2_7i90.0: MD 0: 1x Hostmot2 DPLL v0: accepted, using 1 hm2/hm2_7i90.0: MD 1: 1x Watchdog v0: accepted, using 1 hm2/hm2_7i90.0: MD 3: 4x Encoder v2: accepted, using 4 hm2/hm2_7i90.0: MD 4: 2x PWMGen v0: accepted, using 1 hm2/hm2_7i90.0: MD 5: 4x StepGen v2: accepted, using 4 hm2/hm2_7i90.0: MD 6: 1x LED v0: accepted, using 1 hm2/hm2_7i90.0: 72 I/O Pins used: hm2/hm2_7i90.0: IO Pin 000 (P1-01): StepGen #0, pin Step (Output) hm2/hm2_7i90.0: IO Pin 001 (P1-03): StepGen #0, pin Direction (Output) hm2/hm2_7i90.0: IO Pin 002 (P1-05): StepGen #1, pin Step (Output) hm2/hm2_7i90.0: IO Pin 003 (P1-07): StepGen #1, pin Direction (Output) hm2/hm2_7i90.0: IO Pin 004 (P1-09): Encoder #0, pin A (Input) hm2/hm2_7i90.0: IO Pin 005 (P1-11): Encoder #2, pin A (Input) hm2/hm2_7i90.0: IO Pin 006 (P1-13): Encoder #0, pin B (Input) hm2/hm2_7i90.0: IO Pin 007 (P1-15): Encoder #2, pin B (Input) hm2/hm2_7i90.0: IO Pin 008 (P1-17): Encoder #0, pin Index (Input) hm2/hm2_7i90.0: IO Pin 009 (P1-19): Encoder #2, pin Index (Input) [snip the rest of its 72 pins] AFAIK, there is not an sserial interface, which only talks at 230 kilobaud, available in the 7i90HD. I Hope this helps. Take care Ralph, and stay well. > Thanks again, > -- Ralph > > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users Cheers, Gene Heskett. -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author, 1940) If we desire respect for the law, we must first make the law respectable. - Louis D. Brandeis Genes Web page <http://geneslinuxbox.net:6309/gene> _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
