GPIO control with MK2

[Antoine Roy-Gobeil]

Hello,

I am trying to control the GPIO on the MK2-A810 but I can't get it to work. I'm basically using the following Python script which reuses functions from "mk2_spm_control.py". What am I missing?

Thank you for your help,
Antoine

import sys
import struct

# Set here the SRanger dev to be used:
sr_dev_path = "/dev/sranger_mk2_1"
magic_address = 0x5000
magic_fmt = "<HHHHHHHHHHHHHHHHHHHHHHHHHH"
i_CR_generic_io = 21

# open SRanger, read magic offsets (look at FB_spm_dataexchange.h -> SPM_MAGIC_DATA_LOCATIONS)
def open_sranger():
    sr = open (sr_dev_path, "rw")
    sr.seek (magic_address, 1)
    magic = struct.unpack (magic_fmt, sr.read (struct.calcsize (magic_fmt)))
    sr.close ()
    return magic

magic = open_sranger()
print ("Magic:", magic)

# Copied from "mk2_spm_contro.py"
def CoolRunnerIOWritePort(data):
    sr = open (sr_dev_path, "wb")
    sr.seek (magic[i_CR_generic_io]+4, 1)
    sr.write (struct.pack ("<H", data)) # Start (code what 1: WR, 2: RD, 3: DirReconf), Stop, Dir-, In-, Out-data
    sr.seek (magic[i_CR_generic_io], 1)
    sr.write (struct.pack ("<hh", 1,0)) # Start (code what 1: WR, 2: RD, 3: DirReconf), Stop, Dir-, In-, Out-data
    sr.close ()
    return 1

# Copied from "mk2_spm_contro.py"
def CoolRunnerIOWrite(s):
    data = int (s, 16) # Hex
    CoolRunnerIOWritePort (data)
    print "GPIO WR: 0x%04X" %data

# Copied from "mk2_spm_contro.py"
def CoolRunnerIOWriteDirection(s):
    dirdata = int (s, 16) # Hex
    sr = open (sr_dev_path, "wb")
    sr.seek (magic[i_CR_generic_io], 1)
    sr.write (struct.pack ("<hhH", 3,0, dirdata)) # Start (code what 1: WR, 2: RD, 3: DirReconf), Stop, Dir-, In-, Out-data
    sr.close ()
    print ("GPIO CONF DIRECTION: 0x%04X" %dirdata)
    return 1

# Set direction of all pins to OUTPUT
CoolRunnerIOWriteDirection("0xFFFF")
# Set all pins to ON
CoolRunnerIOWrite("0xFFFF")

[Thorsten Wagner]

Dear Antoine.

Please check line 5 of your skript: The mk2 card might be connected to the block device /dev/sranger_mk23_0.

Thorsten :-)

[Antoine Roy-Gobeil]

Dear Thorsten,

I should have mentionned that the hardware is working properly and is connected to the block device "/dev/sranger_mk2_1" in my setup. I can get the MK2 card to output pulses (using the script "mk2_spm_control.py") but I can't simply turn them ON using "CoolRunnerIOWrite("0xFFFF")". Why is that?

Thank you,
Antoine

[Percy Zahl]

Hey Antoine,

so what exactly is not working, any error? Or just nothing is happening? May be simply the output is "inverted" from what you expect -- using any possibly inverting driver or just a meter to check? Try to toggle 0/1 and see! But I be leave "high" (TTL on) on the GPIO port should be digital 1 also.

One note -- you may need to introduce a few ms delay between both commands to make sure the are both executed.

for example add this line:
add on top:
import time

and use this between dir and data write:
time.sleep(.05)

You may also want to use "os" for read/write -- it seam to be more efficient and I remember some kind of trouble with the other method under some circuimstances I just do not recall, like this:

sr = open (sr_dev_path, "wb")
os.lseek (sr.fileno(), magic[...], 0)
os.write (sr.fileno(), struct.pack ("<h", 0))
...

FYI also:
The GPIO action (R/W/Dir) is executed when you write the "start" flag in the structure.
It is always goingto GPIO Port 0:

From FB_spm_statemaschine.c

                /* Do CoolRunner generic IO ? */
                if (CR_generic_io.start){
                        switch (CR_generic_io.start){
                        case 1: WR_GPIO (GPIO_Data_0, &CR_generic_io.gpio_data_out, 1); break; // write port
                        case 2: WR_GPIO (GPIO_Data_0, &CR_generic_io.gpio_data_in, 0); break; // read port
                        case 3: WR_GPIO (GPIO_Dir_0, &CR_generic_io.gpio_direction_bits, 1); break; // reconfigure port
                        default: break;
                        }
                        CR_generic_io.start=0;
                }

PS: If I find a moment I'll test it tomorrow real quick and see, I have a nice LED dongle for that.... only have a MK3 prototype at home right now ;)

-P

[Percy Zahl]

Dear Antoine, I made you a simplified script, tested it also and it works just fine this way:

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#!/usr/bin/python import sys import time import struct # Set here the SRanger dev to be used: sr_dev_path = "/dev/sranger_mk2_1" magic_address = 0x5000 magic_fmt = "<HHHHHHHHHHHHHHHHHHHHHHHHHH" i_CR_generic_io = 21 # open SRanger, read magic offsets (look at FB_spm_dataexchange.h -> SPM_MAGIC_DATA_LOCATIONS) def open_sranger(): sr = open (sr_dev_path, "rw") sr.seek (magic_address, 1) magic = struct.unpack (magic_fmt, sr.read (struct.calcsize (magic_fmt))) sr.close () return magic def GPIO_setup(dir): sr = open (sr_dev_path, "wb") sr.seek (magic[i_CR_generic_io], 1) sr.write (struct.pack ("<hhHHH", 3,0,dir,0,0)) # Start (code what 1: WR, 2: RD, 3: DirReconf), Stop, Dir-, In-, Out-data sr.close () return 1 def GPIO_write(data): sr = open (sr_dev_path, "wb") sr.seek (magic[i_CR_generic_io], 1) sr.write (struct.pack ("<hhHHH", 1,0,0,0,data)) # Start (code what 1: WR, 2: RD, 3: DirReconf), Stop, Dir-, In-, Out-data sr.close () return 1 print ("Open SR at ", sr_dev_path) magic = open_sranger() print ("Magic:", magic) GPIO_setup (0x00ff) for bits in range(0, 0xff): time.sleep (0.1) GPIO_write (bits)

[Antoine Roy-Gobeil]

Dear Percy,

Thank you very much for this script! It works now!

Have a very nice day,
Antoine