Initial version of Steering Wheel Microcontroller Firmwaresandbox/jsmoeller/WIP

Reads all buttons and sends out CAN bus messages similar to the
previous LIN converter.

Best use thonny as IDE/Editor. Board is available on ttyACM0.
Source code is stored on the board itself as:
- boot.py (blinks board at boot)
- main.py (main script that runs by default)

The steering wheel decoder is in the steering-wheel subfolder.
The monitor folder contains a simple serial monitor printing the CAN message.

You need a CANpico board for this.

The firmware used/tested with this code is in the firmware-CANpico subfolder.

Signed-off-by: Jan-Simon Moeller <jsmoeller@linuxfoundation.org>
Change-Id: I9751b6e0e7a2fc6cb6c82bb0a64719c6aa6ebe11

9 files changed, 344 insertions, 0 deletions

diff --git a/.gitreview b/.gitreview
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+++ b/.gitreview
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+[gerrit]
+host=gerrit.automotivelinux.org
+port=29418
+project=src/steering-wheel-microcontroller
+defaultbranch=master
diff --git a/LICENSE b/LICENSE
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+++ b/LICENSE
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+Unless otherwise stated in the (sub-)folder or file, this software 
+is under the Apache-2.0 license.
+
+The shorthand used in the files is:
+
+SPDX-License-Identifier: Apache-2.0
+
+
+The license statement is below:
+
+Copyright 2022 The Linux Foundation
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
\ No newline at end of file
diff --git a/README.md b/README.md
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--- /dev/null
+++ b/README.md
diff --git a/firmware-CANpico/LICENSE b/firmware-CANpico/LICENSE
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--- /dev/null
+++ b/firmware-CANpico/LICENSE
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+As per https://docs.micropython.org/en/v1.19.1/license.html ,
+the micropython sources that are used to build this firmware
+are under MIT License.
\ No newline at end of file
diff --git a/firmware-CANpico/firmware-20220805.uf2 b/firmware-CANpico/firmware-20220805.uf2
new file mode 100644
index 0000000..9d99dcd
--- /dev/null
+++ b/firmware-CANpico/firmware-20220805.uf2
diff --git a/src/monitor/boot.py b/src/monitor/boot.py
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+++ b/src/monitor/boot.py
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+# SPDX-License-Identifier: Apache-2.0
+# (C) The Linux Foundation
+# Author: Jan-Simon Moeller (jsmoeller@linuxfoundation.org)
+
+from machine import Pin
+import time
+
+led = Pin(25, Pin.OUT)
+i = 8
+
+
+led.value(0)
+
+while i > 0:
+    led.toggle()
+    time.sleep(0.1)
+    i = i-1
+
+
+
+
+
+
diff --git a/src/monitor/main.py b/src/monitor/main.py
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+++ b/src/monitor/main.py
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+# SPDX-License-Identifier: Apache-2.0
+# (C) The Linux Foundation
+# Author: Jan-Simon Moeller (jsmoeller@linuxfoundation.org)
+
+from rp2 import *
+from time import sleep
+
+
+led = Pin(25, Pin.OUT)
+led.value(0)
+
+c = CAN()
+
+while True:
+    frames = c.recv()
+    for frame in frames:
+        led.toggle()
+        print(frame)
+    sleep(0.2)
diff --git a/src/steering-wheel/boot.py b/src/steering-wheel/boot.py
new file mode 100644
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+++ b/src/steering-wheel/boot.py
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+# SPDX-License-Identifier: Apache-2.0
+# (C) The Linux Foundation
+# Author: Jan-Simon Moeller (jsmoeller@linuxfoundation.org)
+
+from machine import Pin
+import time
+
+led = Pin(25, Pin.OUT)
+i = 8
+
+
+led.value(0)
+
+while i > 0:
+    led.toggle()
+    time.sleep(0.1)
+    i = i-1
+
+
+
+
+
diff --git a/src/steering-wheel/main.py b/src/steering-wheel/main.py
new file mode 100644
index 0000000..4a86ad8
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+++ b/src/steering-wheel/main.py
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+# SPDX-License-Identifier: Apache-2.0
+# (C) The Linux Foundation
+# Author: Jan-Simon Moeller (jsmoeller@linuxfoundation.org)
+
+from machine import Pin
+from machine import ADC
+from time import sleep
+import gc
+from rp2 import *
+
+# Enable debug messages over serial (a bit slower)
+DEBUG = 1
+DEBUG2 = 0
+# Enable canbus output
+CANBUS = 1
+# enable only messages on changes
+ONLYNEW = 1
+
+# invert the button pins
+INVERTPINS = 1
+
+if CANBUS:
+    c = CAN()
+    led = Pin(25, Pin.OUT)
+    led.value(0)
+
+oldcandata = bytearray(8)
+
+# Hardware connection
+HORN       = Pin(18, Pin.IN, Pin.PULL_UP)
+LANEASSIST = Pin(17, Pin.IN, Pin.PULL_UP)
+INFOBUTTON = Pin(16, Pin.IN, Pin.PULL_UP)
+AUDIOADC   = ADC(26)
+PHONEADC   = ADC(27)
+CRUISEADC  = ADC(28)
+
+# ADC voltage/resolution conversion
+conversion = 3.3/65535
+
+def strhex(c):
+    return str("0x%02X" % int(c))
+def int2hex(c):
+    return str("%02X" % int(c))
+
+myAUDIObutton = "NONE"
+myPHONEbutton = "NONE"
+myCRUISEbutton = "NONE"
+myAUDIOcan = 0
+myPHONEcan = 0
+myCRUISEcan = 0
+myBUTTONcan = 0
+
+while True:
+    # reset before read
+    myAUDIObutton = "NONE"
+    myPHONEbutton = "NONE"
+    myCRUISEbutton = "NONE"
+    myAUDIOcan = 0
+    myPHONEcan = 0
+    myCRUISEcan = 0
+    myBUTTONcan = 0
+
+    # read values:
+    myLANE = (INVERTPINS - LANEASSIST.value())**2
+    myINFO = (INVERTPINS - INFOBUTTON.value())**2
+    myHORN = (INVERTPINS - HORN.value())**2
+    myAUDIO = float("{:.2f}".format(float(AUDIOADC.read_u16())*conversion))
+    myPHONE = float("{:.2f}".format(float(PHONEADC.read_u16())*conversion))
+    myCRUISE = float("{:.2f}".format(float(CRUISEADC.read_u16())*conversion))
+    
+    # Q'n'd spaghetticode for adc
+    # AUDIO
+    #   Vin = 3.3V                        ADCx
+    #   R1  = 680 Ohm                      | 
+    #                   3.3V o----[=R1=]---x---[=Steering Wheel=]---o GND
+    #
+    # Tipping point = ((V2a-V2b)/2)+V2b
+    #            e.g. ((2.959-2.305)/2)+2.305 ~= 2.6
+    #
+    #             Button      Resistance       Voltage V2    tipping point
+    #   No button pressed:    5.900  Ohm        2.959        -> 2.6
+    #   < :                   1.577  Ohm        2.305        -> 2.0
+    #   > :                     752  Ohm        1.733        -> 1.5
+    #   MODE:                   421  Ohm        1.26         -> 1.0
+    #   - :                     242  Ohm        0.866        -> 0.7
+    #   + :                     132  Ohm        0.536        -> 0.4
+    #   mute:                    57  Ohm        0.255        -> 0
+    #
+    if float(myAUDIO) < 2.60:
+        myAUDIObutton = "<"
+        myAUDIOcan = 128
+        # 0x80
+    if float(myAUDIO) < 2.00:
+        myAUDIObutton = ">"
+        myAUDIOcan = 8
+        #0x08
+    if float(myAUDIO) < 1.50:
+        myAUDIObutton = "MODE"
+        myAUDIOcan = 32
+    if float(myAUDIO) < 1.00:
+        myAUDIObutton = "-"
+        myAUDIOcan = 16
+    if float(myAUDIO) < 0.70:
+        myAUDIObutton = "+"
+        myAUDIOcan = 64
+    if float(myAUDIO) < 0.4:
+        myAUDIObutton = "MUTE"
+        myAUDIOcan = 1
+    if not myINFO:
+        myAUDIOcan = 2
+        
+    # Phone
+    #   Vin = 3.3V                        ADCx
+    #   R1  = 680 Ohm                      | 
+    #                   3.3V o----[=R1=]---x---[=Steering Wheel=]---o GND
+    #
+    # Tipping point = ((V2a-V2b)/2)+V2b
+    #            e.g. ((2.91-1.7)/2)+1.7 ~= 2.3
+    #
+    #             Button      Resistance       Voltage V2    tipping point
+    #   No button pressed:    5.180  Ohm        2.91         -> 2.3
+    #   Hang-up :               753  Ohm        1.7          -> 1.3
+    #   Take call :             242  Ohm        0.866        -> 0.56
+    #   Hands free/voice:        57  Ohm        0.255
+    #
+    if float(myPHONE) < 2.30:
+        myPHONEbutton = "HANGUP"
+        myPHONEcan = 1
+    if float(myPHONE) < 1.30:
+        myPHONEbutton = "TAKECALL"
+        myPHONEcan = 2
+    if float(myPHONE) < 0.56:
+        myPHONEbutton = "HANDSFREE"
+        myPHONEcan = 4
+    
+    # Cruise
+    #   Vin = 3.3V                        ADCx
+    #   R1  = 1000 Ohm                     | 
+    #                   3.3V o----[=R1=]---x---[=Steering Wheel=]---o GND
+    #
+    # Tipping point = ((V2a-V2b)/2)+V2b
+    #            e.g. ((2.58-1.96)/2)+1.96 ~= 2.27
+    #
+    #             Button      Resistance       Voltage V2    tipping point
+    #   No button pressed:    5.180  Ohm        2.58           -> 2.27
+    #   Distance :            1.463  Ohm        1.96           -> 1.70
+    #   Res/+ :                 782  Ohm        1.45           -> 1.19
+    #   Set/-:                  390  Ohm        0.93           -> 0.75
+    #   Limit :                 211  Ohm        0.57           -> 0.44
+    #   Cancel :                101  Ohm        0.30           -> 0.15
+    #   Cruise Enable:            0  Ohm        0 !!
+    #
+    if float(myCRUISE) < 2.27:
+        myCRUISEbutton = "Distance"
+        myCRUISEcan = 1
+    if float(myCRUISE) < 1.70:
+        myCRUISEbutton = "Res/+"
+        myCRUISEcan = 64
+    if float(myCRUISE) < 1.19:
+        myCRUISEbutton = "Set/-"
+        myCRUISEcan = 16
+    if float(myCRUISE) < 0.75:
+        myCRUISEbutton = "Limit"    
+        myCRUISEcan = 2
+    if float(myCRUISE) < 0.44:
+        myCRUISEbutton = "Cancel"
+        myCRUISEcan = 8
+    if float(myCRUISE) < 0.15:
+        myCRUISEbutton = "CruiseEnable"
+        myCRUISEcan = 128
+
+
+    if not myLANE:
+        myBUTTONcan = 1
+    if not myINFO:
+        myBUTTONcan = 2
+    if not myHORN:
+        myBUTTONcan = 128
+
+    if DEBUG:
+        print("LANE       - %s" % ( 1 - myLANE ) )
+        print("INFO       - %s" % ( 1 - myINFO ) )
+        print("HORN       - %s" % ( 1 - myHORN ) )
+        print("AUDIOADC   - %s" % myAUDIO)
+        print("AUDIObutton  %s" % myAUDIObutton)
+        print("PHONEADC   - %s" % myPHONE)
+        print("PHONEbutton  %s" % myPHONEbutton)
+        print("CRUISEADC  - %s" % myCRUISE)
+        print("CRUISEbutton %s" % myCRUISEbutton)
+        print("")
+        print("ALLOC - %s" % gc.mem_alloc())
+        print("FREE  - %s" % gc.mem_free())
+        print("")
+
+    #CanMessage:
+    #Button ADC0  ADC1  ADC2 AUDIO PHONE CRUISE BUTTONS
+    # 0x00  0x00  0x00  0x00  0x00  0x00  0x00  0x00
+    if DEBUG2:
+        print(  "CanMessage: %s,%s,%s,%s,%s,%s,%s,%s" % 
+               ( strhex(myBUTTONcan), strhex(myAUDIO*10), strhex(myPHONE*10), strhex(myCRUISE*10),
+                 strhex(myAUDIOcan), strhex(myPHONEcan), strhex(myCRUISEcan), strhex(myBUTTONcan) )
+             )
+
+    if CANBUS:
+        # send out can message
+        canid = 0x21
+#        candata = bytearray([myBUTTONcan, int(myAUDIO*10),
+#                              int(myPHONE*10), int(myCRUISE*10),
+#                              myAUDIOcan, myPHONEcan,
+#                              myCRUISEcan, myBUTTONcan])
+        candata = bytearray([myBUTTONcan, 0,
+                              0, 0,
+                              myAUDIOcan, myPHONEcan,
+                              myCRUISEcan, myBUTTONcan])
+        if DEBUG2:
+            print(candata)
+        
+        if ONLYNEW:
+            # only send on differences
+            if not candata == oldcandata:
+                oldcandata = candata
+                f = CANFrame(CANID(canid), data=bytes(candata))
+                led.toggle()
+                c.send_frame(f)
+                sleep(0.01)
+                while f.get_timestamp() is None:
+                    print("*****************waiting for can frame to be sent")
+                    sleep(0.1)
+                led.toggle()
+            else:
+                continue
+        else:
+            # always send
+            f = CANFrame(CANID(canid), data=bytes(candata))
+            led.toggle()
+            c.send_frame(f)
+            sleep(0.01)
+            while f.get_timestamp() is None:
+                print("*****************waiting for can frame to be sent")
+                sleep(0.1)
+            led.toggle()
+        
+    else:
+        # do nothing
+        sleep(0.01)
+    sleep(0.04)
+    if DEBUG:
+        # debug output on serial is slower
+        sleep(0.05)
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