first version to set DC2PD preamplifier gain via MCP4725 chip on I2C bus

DC2PD_preamp_set.sh

@@ -0,0 +1,19 @@
+#!/bin/sh
+
+if [ "$#" -lt  "2" ]
+then
+        echo "No arguments supplied"
+else
+        CHIPADDRESS=$1
+        dB=$2
+
+        echo "Setting DC2PD preamplifier at address $CHIPADDRESS to $dB dB gain."
+
+	DAC=`echo "(4095 * ($dB - 7.5))/(55.5 - 7.5)" | bc`
+
+        HIGHBYTE=`echo $(($DAC >> 4))`
+        LOWBYTE=`echo $((($DAC << 4) & 255))`
+
+        i2cset -y 0 $CHIPADDRESS 0x60 $HIGHBYTE $LOWBYTE i # write 3000 to DAC & EEPROM
+fi
+