Add initial version of control script

Add mpads.sh: basic bash script to control the serial mux and sd mux board. Uses i2c-tools to control the registers on the MCP23017

mpads.sh

@@ -0,0 +1,128 @@
+#/bin/bash
+
+# http://ww1.microchip.com/downloads/en/DeviceDoc/20001952C.pdf
+
+
+
+POSITIONAL=()
+
+# default values for I2C BUS, DEVICE and options
+BUS=1
+DEVICE=0x20
+DETECT=0
+INIT=0
+SERIAL=-1
+POWER=0
+CARD=-2
+
+# read options from command line
+while [[ $# -gt 0 ]]
+do
+	key="$1"
+
+	case $key in
+	-b|--bus)   # this has to be I2C bus as in /dev/i2c-
+		BUS=$2
+		shift
+		shift
+		;;
+	-a|--address)
+		DEVICE=$2
+		shift
+		shift
+		;;
+	-d|--detect)
+	    	DETECT=1
+		shift # past argument
+		;;
+	-i|--init)
+		INIT=1
+		shift # argument
+		;;
+	-s|--serial)
+		SERIAL=$2
+		shift # argument
+		shift # value
+		;;
+	-c|--card)
+                CARD=$2
+                shift # argument
+                shift # value
+                ;;
+	--pon)
+		# ports range from 0 to 7, when turning on increase by one to get from 1 to 8
+		POWER=$(($2+1))
+		shift
+		shift
+		;;
+	--poff)
+		# ports range from 0 to 7, when turning off invert sign, decrease by one to get from -1 to -8
+		POWER=$((0-$2-1))
+		shift
+		shift
+		;;
+	*)    # unknown option
+		POSITIONAL+=("$1") # save it in an array for later
+		shift # past argument
+		;;
+	esac
+done
+
+set -- "${POSITIONAL[@]}" # restore positional parameters
+
+echo "Using device $DEVICE on i2c bus $BUS"
+
+if [[ $DETECT -eq 1 ]]
+then
+	# detect i2c devices on bus
+	echo "Running i2cdetect on i2c bus $DEVICE"
+	i2cdetect -y $BUS
+fi
+
+if [[ $INIT -eq 1 ]]
+then
+	# set all pins as outputs
+	echo "Initializing MCP23017 on i2c bus $DEVICE"
+	i2cset -y $BUS $DEVICE 0x0 0x0
+	i2cset -y $BUS $DEVICE 0x1 0x0
+	i2cset -y -m 0xF0 $BUS $DEVICE 0x12 0x80 # value 0x80 turns enable pin high -> disable sd master
+fi
+
+if [[ $SERIAL -gt -1 ]]
+then
+	# only change lowest 3 bits, read other bits from devices
+	echo "Selecting serial $SERIAL"
+	i2cset -y -m 0x07 $BUS $DEVICE 0x12 $SERIAL
+fi
+
+if [[ $POWER -gt 0 ]]
+then
+	POWER=$(($POWER-1))
+	MASK=$((1<<$POWER)) # calculate bitmask
+	echo "Turning on port $POWER"
+	i2cset -y -m $MASK $BUS $DEVICE 0x13 0xFF
+fi
+
+if [[ $POWER -lt 0 ]]
+then
+	POWER=$((0-$POWER-1))
+	MASK=$((1<<$POWER))
+	echo "Turning off port $POWER"
+	i2cset -y -m $MASK $BUS $DEVICE 0x13 0x0
+fi
+
+if [[ $CARD -eq -1 ]]
+then
+	echo "Disconnecting card from master; all cards on slaves"
+	# use -m 0xF0 to only update highbyte, read rest from device
+	i2cset -y -m 0xF0 $BUS $DEVICE 0x12 0x80 # value 0x80 turns enable pin high -> disable sd master
+fi
+
+if [[ $CARD -gt -1 ]]
+then
+	echo "Connecting card $CARD to master, disconnecting from slave"
+	CARD=$(($CARD&0x07)) # make sure only lowest 3 bits are used, rest is set to zero
+	CARD=$(($CARD<<4)) # shift to highbyte
+	i2cset -y -m 0xF0 $BUS $DEVICE 0x12 $CARD # use -m 0xF0 to only update highbyte, read rest from device
+fi
+