On Tuesday 14 September 2021 15:36:49 John Figie wrote:
> So I am still curious if connecting some device to a Mesa Anything I/O
> board such as the 7I80 using SPI is easy or difficult to do.
>
> I see that there was some work proposed for a SPI sub-driver for
> hostmot2
> <http://wiki.linuxcnc.org/cgi-bin/wiki.pl?SPI_Sub-Driver_For_Hostmot2>
> but maybe not much has changed since this was added to the wiki.
>
> my understanding is that this would work for some SPI communications
> between a card like a 7I80 and some device. The driver would allow a
> user to configure the SPI comms for the number of SPI channels and the
> amount of data frames transferred with each request.
>
> I see that some I/O boards already use SPI communications, along with
> discrete I/O such as the 7I65. So I suppose one could make a device
> that uses the SPI interface and pretends to be the DACs from a 7I65,
> but that would be kind of limited as the communications is probably
> just output only.
>
No, your info, and the wiki are out of date, its 2 way using the rpspi.ko
driver since about 4 years back up the log and in my case. a 7i90HD
card, buffered and protected by a trio of 7i42TA's which in addition to
gobbling up noise that can destroy the fpga in the 7i90HD, supplies
those ultra handy little green screw terminals to wire it all up with.
My rpi4 is sending 32 bit packets to the 7i90 over an spi bus at about 41
megabaud, and getting data back from the 7i90HD at 25 megabaud. The rpi3
before it did the same. Doing it with the 7i90HD, my rpi4's ethernet
port is still free, so that pi is just another address on my home
private network, which is NATted from my internet address, so I can
carve steel with a converted 1950 vintage Sheldon lathe and browse the
world with firefox at the same time if I want to. I could do that with a
pi3b but you could hear the lathe stumble a bit now and then.
> But what about the 7I46? Is that I/O card supported by LinuxCNC in
> some way? How are the SPI ports configured?
Don't know anything about the 7i46, you'll have to ask Peter C. Wallace,
who I think is reading these lists.
> Is there still interest in the SPI sub-diver for hosmot2? Has the
> community moved on to better ways to interface to other devices?
The rpspi.ko driver, by a Swedish Uni prof named Bertho Stultans, was
contributed to LinuxCNC several years ago, and has been updated at least
twice since. It Just Works if you follow the cabling instructions.
Effectively the spi disappears and all ypu see at lcnc launch is the
cards registration, which looks like this:
hm2_rpspi: ERROR: Failed to execute '/sbin/rmmod spi_bcm2835'
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:0x0xb4300000, spi:0x0xb4304000, aux:0x0xb4315000
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)
hm2/hm2_7i90.0: IO Pin 010 (P1-21): Encoder #1, pin A (Input)
hm2/hm2_7i90.0: IO Pin 011 (P1-23): Encoder #3, pin A (Input)
hm2/hm2_7i90.0: IO Pin 012 (P1-25): Encoder #1, pin B (Input)
hm2/hm2_7i90.0: IO Pin 013 (P1-27): Encoder #3, pin B (Input)
hm2/hm2_7i90.0: IO Pin 014 (P1-29): Encoder #1, pin Index (Input)
hm2/hm2_7i90.0: IO Pin 015 (P1-31): Encoder #3, pin Index (Input)
hm2/hm2_7i90.0: IO Pin 016 (P1-33): StepGen #2, pin Step (Output)
hm2/hm2_7i90.0: IO Pin 017 (P1-35): StepGen #2, pin Direction
(Output)
hm2/hm2_7i90.0: IO Pin 018 (P1-37): StepGen #3, pin Step (Output)
hm2/hm2_7i90.0: IO Pin 019 (P1-39): StepGen #3, pin Direction
(Output)
hm2/hm2_7i90.0: IO Pin 020 (P1-41): PWMGen #0, pin Out0 (PWM or Up)
(Output)
hm2/hm2_7i90.0: IO Pin 021 (P1-43): PWMGen #0, pin Out1 (Dir or Down)
(Output)
hm2/hm2_7i90.0: IO Pin 022 (P1-45): IOPort
hm2/hm2_7i90.0: IO Pin 023 (P1-47): IOPort
hm2/hm2_7i90.0: IO Pin 024 (P2-01): IOPort
hm2/hm2_7i90.0: IO Pin 025 (P2-03): IOPort
hm2/hm2_7i90.0: IO Pin 026 (P2-05): IOPort
hm2/hm2_7i90.0: IO Pin 027 (P2-07): IOPort
hm2/hm2_7i90.0: IO Pin 028 (P2-09): IOPort
hm2/hm2_7i90.0: IO Pin 029 (P2-11): IOPort
hm2/hm2_7i90.0: IO Pin 030 (P2-13): IOPort
hm2/hm2_7i90.0: IO Pin 031 (P2-15): IOPort
hm2/hm2_7i90.0: IO Pin 032 (P2-17): IOPort
hm2/hm2_7i90.0: IO Pin 033 (P2-19): IOPort
hm2/hm2_7i90.0: IO Pin 034 (P2-21): IOPort
hm2/hm2_7i90.0: IO Pin 035 (P2-23): IOPort
hm2/hm2_7i90.0: IO Pin 036 (P2-25): IOPort
hm2/hm2_7i90.0: IO Pin 037 (P2-27): IOPort
hm2/hm2_7i90.0: IO Pin 038 (P2-29): IOPort
hm2/hm2_7i90.0: IO Pin 039 (P2-31): IOPort
hm2/hm2_7i90.0: IO Pin 040 (P2-33): IOPort
hm2/hm2_7i90.0: IO Pin 041 (P2-35): IOPort
hm2/hm2_7i90.0: IO Pin 042 (P2-37): IOPort
hm2/hm2_7i90.0: IO Pin 043 (P2-39): IOPort
hm2/hm2_7i90.0: IO Pin 044 (P2-41): IOPort
hm2/hm2_7i90.0: IO Pin 045 (P2-43): IOPort
hm2/hm2_7i90.0: IO Pin 046 (P2-45): IOPort
hm2/hm2_7i90.0: IO Pin 047 (P2-47): IOPort
hm2/hm2_7i90.0: IO Pin 048 (P3-01): IOPort
hm2/hm2_7i90.0: IO Pin 049 (P3-03): IOPort
hm2/hm2_7i90.0: IO Pin 050 (P3-05): IOPort
hm2/hm2_7i90.0: IO Pin 051 (P3-07): IOPort
hm2/hm2_7i90.0: IO Pin 052 (P3-09): IOPort
hm2/hm2_7i90.0: IO Pin 053 (P3-11): IOPort
hm2/hm2_7i90.0: IO Pin 054 (P3-13): IOPort
hm2/hm2_7i90.0: IO Pin 055 (P3-15): IOPort
hm2/hm2_7i90.0: IO Pin 056 (P3-17): IOPort
hm2/hm2_7i90.0: IO Pin 057 (P3-19): IOPort
hm2/hm2_7i90.0: IO Pin 058 (P3-21): IOPort
hm2/hm2_7i90.0: IO Pin 059 (P3-23): IOPort
hm2/hm2_7i90.0: IO Pin 060 (P3-25): IOPort
hm2/hm2_7i90.0: IO Pin 061 (P3-27): IOPort
hm2/hm2_7i90.0: IO Pin 062 (P3-29): IOPort
hm2/hm2_7i90.0: IO Pin 063 (P3-31): IOPort
hm2/hm2_7i90.0: IO Pin 064 (P3-33): IOPort
hm2/hm2_7i90.0: IO Pin 065 (P3-35): IOPort
hm2/hm2_7i90.0: IO Pin 066 (P3-37): IOPort
hm2/hm2_7i90.0: IO Pin 067 (P3-39): IOPort
hm2/hm2_7i90.0: IO Pin 068 (P3-41): IOPort
hm2/hm2_7i90.0: IO Pin 069 (P3-43): IOPort
hm2/hm2_7i90.0: IO Pin 070 (P3-45): IOPort
hm2/hm2_7i90.0: IO Pin 071 (P3-47): IOPort
hm2/hm2_7i90.0: registered
MOTION: setting Traj cycle time to 1000000 nsecs
MOTION: setting Servo cycle time to 1000000 nsecs
note: MAXV max: 2.000 units/sec 120.000 units/min
note: LJOG max: 2.000 units/sec 120.000 units/min
note: LJOG default: 1.350 units/sec 81.000 units/min
note: jog_order='ZX'
note: jog_invert={'X'}
> Yes I know that the distance that SPI works over is limited, but on
> the other hand it is a pretty simple interface and the data rates can
> easily be 10Mbits/sec if limited to short distances like 10 - 20 cm.
My data cable is about 1.6". I mounted the r-pi upside down so its a
straight shot from the 44pin pi header to the 26 pin socket on the
7i90HD. No cable twists needed.
> Regards,
>
> John Figie
>
> _______________________________________________
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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)
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>
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