Add Modbus registers to Readme

Add Modbus registers to README and add example

README.md

@@ -11,5 +11,60 @@ Please note that this also means that the PIC has control over the RS485 bus. If
 I'll release a version of the PIC firmware soon that will only do the CT measurements, and will not use the RS485 bus, nor use the P1 port.
 On this version the ESP32 will handle everything else.
 
+## Modbus Registers
+
+Modbus RTU address is fixed to 0x0A, speed is 9600 bps 
+
+
+Input Registers (FC=04)(Read Only):
+
+
+
+    Register  Register  
+     Address   length (16 bits)
+     0x0000      1       Sensorbox version 2             = 0x0014 = 4 wire, CW rotation
+                                                           0x0015 = 4 wire, CCW rotation
+                                                           0x0016 = 3 wire, CW rotation      
+                                                           0x0017 = 3 wire, CCW rotation  
+     0x0001      1       DSMR Version(MSB),CT's or P1(LSB) 0x3283 = DSMR version 50, P1 port connected (0x80) CT's Used (0x03)                    
+     0x0002      2       Volts L1 (32 bit floating point), Smartmeter P1 data
+     0x0004      2       Volts L2 (32 bit floating point), Smartmeter P1 data
+     0x0006      2       Volts L3 (32 bit floating point), Smartmeter P1 data
+     0x0008      2       Amps L1 (32 bit floating point), Smartmeter P1 data
+     0x000A      2       Amps L2 (32 bit floating point), Smartmeter P1 data
+     0x000C      2       Amps L3 (32 bit floating point), Smartmeter P1 data
+     0x000E      2       Amps L1 (32 bit floating point), CT imput 1
+     0x0010      2       Amps L2 (32 bit floating point), CT input 2
+     0x0012      2       Amps L3 (32 bit floating point), CT input 3
+
+    Holding Registers (FC=06)(Write):
+
+     Register  Register  
+     Address   length (16 bits) 
+     0x0800      1       Field rotation setting (bit 0)      00000000 0000000x -> 0= Rotation right 1= Rotation Left
+                         3/4 wire configuration (bit 1)      00000000 000000x0 -> 0= 4Wire, 1= 3Wire
+
+## Example:
+
+    Request Sensorbox2 data:
+    0a 04 00 00 00 14 f1 7e
+
+    Sensorbox2 replies with:
+    0a 04 28 00 14 32 83 43 66 80 00 43 66 4c cd 43 69 19 9a 3e 12 9a 61 3f 9f 83 80 be 41 4a 5a 3b ea 00 3b bb 6f f3 6b 3a 45 8d e3 ca cb
+    4 wire CW --^^
+    DSMR ver(50) --^^
+    P1 + CT connected ^^
+    Volts L1 ------------| 230.5 V  |			 
+    					 
+    Request 3 wire grid setting:
+    0a 06 08 00 00 02 0b 10		
+
+    Next sensorbox2 data:
+    0a 04 28 00 16 32 03 43 66 e6 66 43 66 80 00 43 69 19 9a 3d 66 9c 53 3f 97 99 d2 be a2 8a 28 bb 59 73 10 bb 08 29 4d 3b 8f 23 79 ca e6 			 
+    ------------^^ changed to 3 wire, CW setting.
+
+
+
+