document howo to enable all the eqep pins

Author: pdp7

Adafruit_BBIO/Encoder.py

@@ -1,13 +1,56 @@
 #!/usr/bin/python
 
 # ===========================================================================
-# Adafruit_BBIO.Encoder.QEP Class
+# Adafruit_BBIO.Encoder Class
 # ===========================================================================
-
 # refers to graycatlabs/PyBBIO/bbio/libraries/RotaryEncoder/rotary_encoder.py
-# /sys/devices/platform/ocp/48302000.epwmss/48302180.eqep/position
-# /sys/devices/platform/ocp/48304000.epwmss/48304180.eqep/position
-# /sys/devices/platform/ocp/48300000.epwmss/48300180.eqep/position
+
+# BeagleBone must boot with cape-universal enabled
+# and load the cape-universala overlay in order to
+# use all the eQEP pins
+#
+# Install the latest Device Tree overlays:
+# ========================================
+# sudo apt-get upgrade bb-cape-overlays
+#
+# File: /boot/uEnv.txt
+# ====================
+# uname_r=4.4.62-ti-r99
+# cmdline=coherent_pool=1M quiet cape_universal=enable
+# cape_enable=bone_capemgr.enable_partno=cape-universala
+#
+# File: /sys/devices/platform/bone_capemgr/slots
+# ==============================================
+# 0: PF----  -1 
+# 1: PF----  -1 
+# 2: PF----  -1 
+# 3: PF----  -1 
+# 4: P-O-L-   0 Override Board Name,00A0,Override Manuf,cape-universala
+#
+# eqep0: P9_27, P9_92
+# ===================
+# config-pin P9_27 qep
+# config-pin P9_92 qep # alias for P9_42.1
+# cat /sys/devices/platform/ocp/48300000.epwmss/48300180.eqep/position
+#
+# eqep1: P8.33, P8.35
+# ===================
+# config-pin P8.33 qep 
+# config-pin P8.35 qep
+# cat /sys/devices/platform/ocp/48302000.epwmss/48302180.eqep/position
+# 
+# eqep2: P8.11, P8.12
+# ===================
+# config-pin P8.11 qep 
+# config-pin P8.12 qep 
+# cat /sys/devices/platform/ocp/48304000.epwmss/48304180.eqep/position
+#
+# alternate pins for eqep2 (mutually exclusive)
+# eqep2b: P8.41, P8.42
+# ====================
+# config-pin P8.41 qep 
+# config-pin P8.42 qep 
+# cat /sys/devices/platform/ocp/48304000.epwmss/48304180.eqep/position
 
 import os
 
@@ -51,6 +94,7 @@ class RotaryEncoder(object):
     '%s/48302000.epwmss/48302180.eqep' % OCP_PATH,
     '%s/48304000.epwmss/48304180.eqep' % OCP_PATH
   ]
+
   EQEP0 = 0
   EQEP1 = 1
   EQEP2 = 2

test/test_rotary.py

@@ -1,6 +1,9 @@
 #!/usr/bin/python
 
 import Adafruit_BBIO.Encoder as Encoder
+# /sys/devices/platform/ocp/48300000.epwmss/48300180.eqep/position 0
+# /sys/devices/platform/ocp/48302000.epwmss/48302180.eqep/position 0
+# /sys/devices/platform/ocp/48304000.epwmss/48304180.eqep/position 882
 # P8.11: eqep2b_in
 # P8.12: eqep2a_in
 # run "config-pin p8.11 qep && config-pin p8.12 qep"