chipmisc: Add support for configuring ad5206 digipots

Support an "ad5206" config section so that one can configure the
digipots found on Reprap "RAMBo" boards.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

1 files changed, 30 insertions, 0 deletions

diff --git a/config/example-extras.cfg b/config/example-extras.cfg
index ec9de90b..b3091e77 100644
--- a/config/example-extras.cfg
+++ b/config/example-extras.cfg
@@ -81,3 +81,33 @@
 #   enabled, and then the 'value' parameter can be specified using the
 #   desired amperage for the stepper. The default is to not scale the
 #   'value' parameter.
+
+
+# Statically configured AD5206 digipots connected via SPI bus (one may
+# define any number of sections with an "ad5206" prefix).
+#[ad5206 my_digipot]
+#enable_pin:
+#   The pin corresponding to the AD5206 chip select line. This pin
+#   will be set to low at the start of SPI messages and raised to high
+#   after the message completes. This parameter must be provided.
+#channel_1:
+#channel_2:
+#channel_3:
+#channel_4:
+#channel_5:
+#channel_6:
+#   The value to statically set the given AD5206 channel to. This is
+#   typically set to a number between 0.0 and 1.0 with 1.0 being the
+#   highest resistance and 0.0 being the lowest resistance. However,
+#   the range may be changed with the 'scale' parameter (see
+#   below). If a channel is not specified then it is left
+#   unconfigured.
+#scale:
+#   This parameter can be used to alter how the 'channel_x' parameters
+#   are interpreted. If provided, then the 'channel_x' parameters
+#   should be between 0.0 and 'scale'. This may be useful when the
+#   AD5206 is used to set stepper voltage references. The 'scale' can
+#   be set to the equivalent stepper amperage if the AD5206 were at
+#   its highest resistance, and then the 'channel_x' parameters can be
+#   specified using the desired amperage value for the stepper. The
+#   default is to not scale the 'channel_x' parameters.