piio

gpio

i2c

    piio function 11 output
    piio output 11 1

http://elinux.org/RPi_GPIO_Code_Samples

RasPi.TV

package require piio

piio function 21 output

proc blink {{state 1}} {
    piio output 21 $state
    after 500 [list blink [expr {!$state}]]
}

blink
vwait forever

# A tcl script to flash morse code on an LED on a Raspberry Pi 3 B+ 
# 30 March 2017
# Wiring setup: 5mm diameter LED in series with a 330 ohm resistor wired from gpio16 (pin36) to ground (pin34) 
# morse-code code from: http://wiki.tcl.tk/3371

# turn "on" a gpio pin which has previously been set to output mode 
proc flash {gpio n} { 
    piio output $gpio 1
    pause $n
    piio output $gpio 0
    pause 1
}

# A simple pause while running the event loop, in terms of basic time units
proc pause n {
    global t
    after [expr {$t * $n}] set ok 1
    vwait ok
}

set MORSE_CODE {
    "!" "---."         "\"" ".-..-."        "$" "...-..-"        "'" ".----."
    "(" "-.--."         ")" "-.--.-"        "+" ".-.-."        "," "--..--"
    "-" "-....-" "." ".-.-.-"        "/" "-..-."
    ":" "---..." ";" "-.-.-."        "=" "-...-"        "?" "..--.."
    "@" ".--.-." "[" "-.--."        "]" "-.--.-"        "_" "..--.-"
    "0" "-----"         "1" ".----"        "2" "..---"        "3" "...--"
    "4" "....-"         "5" "....."        "6" "-...."        "7" "--..."
    "8" "---.."         "9" "----."
    "A" ".-"         "B" "-..."        "C" "-.-."        "D" "-.."
    "E" "."         "F" "..-."        "G" "--."        "H" "...."
    "I" ".."         "J" ".---"        "K" "-.-"        "L" ".-.."
    "M" "--"         "N" "-."        "O" "---"        "P" ".--."
    "Q" "--.-"         "R" ".-."        "S" "..."        "T" "-"
    "U" "..-"         "V" "...-"        "W" ".--"        "X" "-..-"
    "Y" "-.--"         "Z" "--.."
}

# The code to translate text to morse code and play it
proc morse {gpio str wpm} {
    global t MORSE_CODE
    set t [expr {1200 / $wpm}]
    # Backslash and space are special cases in various ways
    set map {"\\" {} " " {[pause 4]}}
    # Append each item in the code to the map, with an inter-letter pause after
    foreach {from to} $MORSE_CODE {lappend map $from "$to\[pause 3\]"}
    # Convert to dots and dashes
    set s [string map $map [string toupper $str]]
    puts "Morse string: $s"
    # Play the dots and dashes by substituting commands for them (dash displays for 4 times longer than a dot)
    # Pauses between flashes has relative length 1 (same length as a dot flash), pause at end of letter = 4 ,pause between words=8 
    puts "commands to be executed:[string map { "." "[flash $gpio 1]" "-" "[flash $gpio 4]" } $s]"
    subst [string map { "." "[flash $gpio 1]" "-" "[flash $gpio 4]" } $s]
    return
}

# This script requires the piio package (http://chiselapp.com/user/schelte/repository/piio/wiki?name=piio)
# You will have to download and follow the instructions to compile before using this package
package require piio

# prepare the gpio for output
set gpio 16 
piio function $gpio output

set words_per_minute 5

# Translate a text message to morse code flashes
morse $gpio "Hello World" $words_per_minute

https://www.raspberrypi.org/products/sense-hat/

# i2c_dump.tcl
# A script to iterate over all i2c busses, addresses and registers in sequence and dump their contents to stdout
# vh, 12 Apr 2017

set result [package require piio]
puts "package piio loaded: $result"

proc scan_i2cbus {bus_low {bus_high ""}} {

   if  {$bus_high == ""} {set bus_high $bus_low}

      # Iterate over the busses (specified by user) 
      for {set bus $bus_low} {$bus<=$bus_high} {incr bus} {

        puts "working on bus: $bus"

        # check all the addresses from zero to 256
        for {set address 0} {$address < 256} {incr address} {

                scan_i2caddress $bus $address
       }
    }

    puts "Scan finished."
    return
}

proc scan_i2caddress {bus address} {

        # puts "working on bus: $bus, address=$address"

        # if we can get a handle to this address, also search for registers
        if {![catch {set i2c_h [twowire twowire $bus $address]} err ]} {

                # puts "found device at address=$address (handle=$i2c_h)"

                # Check all registers from 0 to 255
                for {set register 0} {$register <=256} {incr register} {

                        if {![catch {set value [twowire readregbyte $i2c_h $register]} err ]} {

                                if {$value > 0} {

                                        puts "bus=$bus, address=[format %3d $address] (0x[format %2.2X $address]), register=[format %3d $register] (0x[format %2.2X $register]), data byte = [format %4d $value] = 0x[format %2.2X $value] = [format %08b $value]"
                                          } else {

                                        # We didn't find any data at that register
                                        # puts "no data at register value $register (no error)"
                                }

                        } else {
                                
                                # We didn't find any data at that register
                                #puts "no data at register value $register (err=$err)"
                        }
                 }

                close $i2c_h
        }

        return
}

puts "Scanning all busses, addresses and registers..."
scan_i2cbus 0 1
puts "--------------------------"

# Scan only one specific address
# set bus 1
# set address 92; aka 0x5c
# puts "Scanning the bus#$bus, address $address"
# scan_i2caddress $bus $address

puts "done."

# lps25h.tcl - script to exercise the temperature/pressure functions of the ST Electonics LSP25H sensor
# Device: LPS25H temperature/pressure sensor at i2c bus 1 address 0x5c.  
# The sensor tested here is part of the SenseHat (https://www.raspberrypi.org/products/sense-hat/) for a Raspberry Pi.
# I2C scripting example using piio package
# vh, 15 April 2017
# 
# Reference material - st.com has created great reference material.  This script was made with the documentation provided here:
# A.  LPS25H data sheet - http://www.st.com/resource/en/datasheet/lps25h.pdf
# B.  How to interpret temperature and pressure reading for the LPS25H - http://www.st.com/resource/en/technical_note/dm00242306.pdf
# C.  Hardware and software guidelines for use of LPS25H pressure sensor http://www.st.com/content/ccc/resource/technical/document/application_note/a0/f2/a5/e7/58/c8/49/b9/DM00108837.pdf/files/DM00108837.pdf/jcr:content/translations/en.DM00108837.pdf
# ---------------------------------------------------------------------------------------------------------------

# a procedure to round a real input value to a specified number of decimal places
proc round {value {num_dec 1}} {

        return [expr round($value * pow(10, $num_dec)) / pow(10,$num_dec)]
}

# A procedure to add two unsigned binary numbers (after http://wiki.tcl.tk/21842)
# this procedures assumes input values in big-endian format
proc bin_add {n1 n2} {
    set sum {}
    set carry 0 
    # reverse the binary string into little-endian format and work through all digits from smallest-to-largest digit
    # puts "[lreverse [split $n1 ""]]  [lreverse [split $n2 ""]]" 
    foreach d1 [lreverse [split $n1 ""]] d2 [lreverse [split $n2 ""]] {
        switch -- [string map {0 ""} "$d1$d2$carry"] { 
            ""  { lappend sum 0; set carry 0}
            1   { lappend sum 1; set carry 0}
            11  { lappend sum 0; set carry 1}
            111 { lappend sum 1; set carry 1}
        } 
    } 

    lappend sum $carry 
    return [string trimleft [join [lreverse $sum] ""] 0] 
}

# convert binary (unsigned binary format) to decimal integer (after http://wiki.tcl.tk/1591)
# this proc checks for sign bit set, and performs 2's complement if necessary
proc bin2dec bin {

    if {$bin == 0} {
        return 0 
    } elseif  {[string index $bin 0] == 1} {
        # If the first bit is set, it means that this is a negative number.  Take the 2's complement.
        set sign "-"
        set bin [string map {0 1 1 0}  $bin]
        set bin [bin_add $bin "1"]

    } else {
        set sign +
    }
  
    set mod [expr {[string length $bin]%8}]
    if {$mod} {
        set mod [expr {8-$mod}]
    }
    set bin [string repeat 0 $mod]$bin
    set len [string length $bin]
    set bin [binary format B* $bin]
    #the else block could do it all, but for illustration...
    if {$len<=8} {
        binary scan $bin cu res
    } elseif {$len <=16} {
        binary scan $bin Su res
    } elseif {$len <=32} {
        if {$len <= 24} {
            set bin [binary format B* 0]$bin
        }
        binary scan $bin Iu res
    } else {
        set res 0
        set blen [expr {$len/8}]
        set pos -1
        while {$blen} {
            incr blen -1
            binary scan $bin x[incr pos]cu next
            set res [expr {$res + $next*(2**($blen*8))} ]
        }
    }
    return $sign$res
}

# A formula provided in reference #3 for calculating altitude from pressure based on US standard atmosphere, 1976
proc From_Pressure_hPa_To_Altitude_US_Std_Atmosphere_1976_m {pressure} {

        set altitude_ft [expr (1. - pow( ($pressure / 1013.25) , 0.190284) ) * 145366.45]
        set altitude_m [expr $altitude_ft / 3.280839895]
        return $altitude_m
}

set result [package require piio]
puts "package piio loaded: $result"

# Get a handle to this device
set bus 1
set address 0x5c; # aka 0x5c
if {[catch {set i2c_h [twowire twowire $bus $address]} err ]} {

        puts "Couldn't get a handle to device at address $address"
        return
}

puts "found device at address=$address (handle=$i2c_h)"

#1  Power down the device (clean start) – WriteByte(CTRL_REG1_ADDR = 0x00); // @0x20 = 0x00  
twowire writeregbyte $i2c_h 0x20 0x00

#2 Turn on the pressure sensor analog front end in single shot mode – WriteByte(CTRL_REG1_ADDR = 0x84); // @0x20 = 0x84
twowire writeregbyte $i2c_h 0x20 0x84

#3 Run one-shot measurement (temperature and pressure), the set bit will be reset by the sensor itself after execution (self-clearing bit) – WriteByte(CTRL_REG2_ADDR = 0x01); // @0x21 = 0x01
twowire writeregbyte $i2c_h 0x21 0x01

#4 Wait until the measurement is completed – ReadByte(CTRL_REG2_ADDR = 0x00); // @0x21 = 0x00

set result 0
while {!$result} {
        after 50 {set data [twowire readregbyte $i2c_h 0x21]}
        vwait data
        # puts "byte read=[format %08b $data]"
        if {$data == 0} {set result 1}
}

puts "TEMPERATURE"

# 5. Read the temperature measurement (2 bytes to read) – Read((u8*)pu8, TEMP_OUT_ADDR, 2); // @0x2B(OUT_L)~0x2C(OUT_H)
set register_0x2b [twowire readregbyte $i2c_h 0x2b]
set register_0x2c [twowire readregbyte $i2c_h 0x2c]
puts "  register_0x2b=[format %2.2X $register_0x2b]([format %08b $register_0x2b]), register_0x2c=[format %2.2X $register_0x2c]([format %08b $register_0x2c])"

# – Temp_Reg_s16 = ((u16) pu8[1]<<8) | pu8[0]; // make a SIGNED 16 bit variable
puts "  register data: 0x[format %2.2X $register_0x2c][format %2.2X $register_0x2b]=[format %08b $register_0x2c][format %08b $register_0x2b]"
puts "  output=[set output [bin2dec [format %08b $register_0x2c][format %08b $register_0x2c]]]"

# Alternative: readregword - this does not seem to work (both bytes 'read' are identical)
# set temp_registers [twowire readregword $i2c_h 0x2b]
# puts "  register data: 0x[format %4.4X $temp_registers]=[format %016b $temp_registers]"
# puts "  output2=[set output [bin2dec [format %08b $temp_registers]]]"

# – Temperature_DegC = 42.5 + Temp_Reg_s16 / 480; // offset and scale
puts "  temperature value=[round [expr 42.5 + $output/480.]] degrees Celcius"

puts "PRESSURE"

# 6.  Read the pressure measurement – Read((u8*)pu8, PRESS_OUT_ADDR, 3); // @0x28(OUT_XL)~0x29(OUT_L)~0x2A(OUT_H)
set register_0x28 [twowire readregbyte $i2c_h 0x28]
set register_0x29 [twowire readregbyte $i2c_h 0x29]
set register_0x2a [twowire readregbyte $i2c_h 0x2a]
puts "  register_0x28=[format %4.4X $register_0x28]([format %08b $register_0x28]), register_0x29=[format %4.4X $register_0x29]([format %08b $register_0x29]), register_0x2a=[format %4.4X $register_0x2a]([format %08b $register_0x2a])"

# – Pressure_Reg_s32 = ((u32)pu8[2]<<16)|((u32)pu8[1]<<8)|pu8[0]; // make a SIGNED 32 bit
puts "  output=[set output [bin2dec [format %08b $register_0x2a][format %08b $register_0x29][format %08b $register_0x28]]]"

# – Pressure_mb = Pressure_Reg_s32 / 4096; // scale
puts "  pressure value=[set pressure [round [expr $output / 4096.] 2 ]] hPa (1 atmosphere at sea level =1013.25 hPa)"
# According to https://www.thoughtco.com/low-and-high-pressure-1434434, normal global pressure ranges are 980 to 1050 hPa

# 7. Check the temperature and pressure values make sense – Reading fixed 760 hPa, means the sensing element is damaged.
if {$output == 760} {puts "  the pressure meter is reading 760 hPa.  It is possibly damaged."}

puts "ALTITUDE"

# Convert pressure to altitude
puts "  Approximate altitude: [round [From_Pressure_hPa_To_Altitude_US_Std_Atmosphere_1976_m $pressure]]m"
# These calculations jive with those at: https://www.weather.gov/epz/wxcalc_pressurealtitude

puts "done."
 
close $i2c_h

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