== Hardware ==

[[Datei:RDC6442G.jpg|RDC6442G 4-axis Lasercontrol|mini]]
[[Datei:RDC6442G Breakout.jpg|Breakout Board|mini]]

* [http://en.rd-acs.com/prod_view.aspx?TypeId=50097&Id=160&FId=t3:50097:3 RDC6442G Herstellerseite]
* [http://www.rogerclark.net/network-aware-laser-cutter-security/ Network aware laser cutter security]
* [https://stefan.schuermans.info/rdcam/ RDCAM Reverse Engineering]
* [http://www.thunderlaser.co.nz/beifen/technical-support/downloads/category/rdc6442g-and-rdwork-software.html RDworks + Manuals]
* [https://github.com/t-oster/VisiCut/issues/404 VisiCut issue]

* [https://edutechwiki.unige.ch/en/Ruida Protocol analysis]
== Protokollanalyse ==
=== UDP ===
* The device listens on a fixed UDP port (DEST_PORT). IPaddress is configurable 172.16.18.11, netmask is 255.255.255.0 fixed, Gateway is configurable 172.16.20.134.
* An RD file is transfered as payload, same commands and syntax as with USB-Serial or USB-MassStorage.
* The payload is split in chunks with a well known maximum size (MTU). (The last packet is usually shorter)
* There is no header, and no arbitration phase, but successful transmission of the first chunk indicates device ready.
* Each chunk starts with a two byte checksum, followed by payload data. Length of the payload is implicit by the UDP datagram size. (Would not work with TCP)
* Each chunk is acknowledged with a single byte response packet:
** 0xc6 if all is well, The next chunk should be sent. A delay of 4 seconds was tested successfully.
** 0x46 if error. TODO: Checksum error and/or busy? A running laser job does not cause a busy condition.
* The first chunk should be retried when 0x46 was received. For subsequent chunks transmission should be aborted.
* No pause is needed after the last chunk. The payload contains a terminator token.

Command line tool usage:

wget https://github.com/jnweiger/ruida-laser/blob/master/udpsendruida.py
python3 udpsendruida.py 192.168.1.100 thunder.rd

=== earlier analysis ===

# Capture mit Wireshark
# Datei > Paketdissektion exportieren > Als JSON
#* Packet summary line
#** Include column headings
#* Packet details:
#** As displayed
#* Packet Bytes
# some more pat foo

=== rdcam.py ===
This python code snippet is probably useful with wireshark. Please add details.

<pre>
def send_command(payload):
data=scramble_bytes(payload)
checksum=sum(data)
b1=checksum&0xff
b0=(checksum>>8)&0xff
return bytes([b0,b1])+data

def encode_number(n,l=5):
res=[]
while n>0:
res.append(n&0x7f)
n>>=7
while len(res)<l:
res.append(0)
res.reverse()
return bytes(res)

def decode_number(x):
fak=1
res=0
for b in reversed(x):
res+=fak*b
fak*=0x80
return res

def format_capture(c):
for p in c:
direction=p["_source"]['layers']['udp']['udp.port']=='50200'
data=unscramble_packet(p,checksum=direction)
line='-> ' if direction else '<- '
line+=' '.join([bytes(x).hex() for x in split_messages(data)])
print(line)

def split_messages(d):
m=[]
res=[m]
for x in d:
if x&0x80:
m=[]
res.append(m)
m.append(x)
return res

def unscramble_packet(p,checksum=False):
string=p["_source"]["layers"]["data"]["data.data_raw"]
if checksum:
return list(bytes.fromhex(string[:4]))+unscramble_string(string[4:])
else:
return unscramble_string(string)

def unscramble_string(s):
return [unscramble(b) for b in bytes.fromhex(s)]

def unscramble(b):
res_b=b-1
if res_b<0: res_b+=0x100
res_b^=0x88
fb=res_b&0x80
lb=res_b&1
res_b=res_b-fb-lb
res_b|=lb<<7
res_b|=fb>>7
return res_b

def scramble(b):
fb=b&0x80
lb=b&1
res_b=b-fb-lb
res_b|=lb<<7
res_b|=fb>>7
res_b^=0x88
res_b+=1
if res_b>0xff:res_b-=0x100
return res_b

def scramble_bytes(bs):
return bytes([scramble(b) for b in bs])
def unscramble_bytes(bs):
return bytes([unscramble(b) for b in bs])
</pre>

=== Data format ===

* Byte = 1 Bit Message Start Indicator + 7 Bit Payload
* Only one message (checksum + command) can be sent per UDP package
* Max UDP package size 1472 bytes including checksum; fragmented by simple cutting (even inside a command)

==== Checksum ====

2 Bytes - sum of scrambled message bytes; MSB first.

Checksum has to be send before message.

'''Network only''' USB does not have checksum.

==== Values ====

{| class="wikitable sortable"
|-
! Value !! Lenght !! Description
|-
|id="VAL-ABSCOORD"| ABSCOORD || 5 Bytes || absolute position relative to job origin in µm
|-
|id="VAL-RELCOORD"| RELCOORD || 2 Bytes || relative position in µm; signed (2s complement)
|-
|id="VAL-SPEED"| SPEED || 5 Bytes || speed in µm/s
|-
|id="VAL-POWER"| POWER || 2 Bytes || power in 0,006103516% (100/2^14)
|-
|id="VAL-CSTRING"| CSTRING || variable zero terminated ||
|}

==== Commands ====

{| class="wikitable sortable"
|-
! Byte squence !! Description !! how sure we are
|-
| C6 01 [[#VAL-POWER|<POWER>]] || 1st laser source min power || 99%
|-
| C6 21 [[#VAL-POWER|<POWER>]] || 2nd laser source min power || 99%
|-
| C6 02 [[#VAL-POWER|<POWER>]] || 1st laser source max power || 99%
|-
| C6 22 [[#VAL-POWER|<POWER>]] || 2nd laser source max power || 99%
|-
| C9 02 [[#VAL-SPEED|<SPEED>]] || movement and/or (not sure) cutting speed || 80%
|-
| D9 00 02 [[#VAL-ABSCOORD|<ABSCOORD>]] || move X || 99%
|-
| D9 00 03 [[#VAL-ABSCOORD|<ABSCOORD>]] || move Y || 50%
|-
| D9 00 04 [[#VAL-ABSCOORD|<ABSCOORD>]] || move Z || 50%
|-
| D9 00 05 [[#VAL-ABSCOORD|<ABSCOORD>]] || move U || 50%
|-
| CC || ACK from machine || 99%
|-
| CD || ERR from machine || 99%
|-
| DA 00 XX XX || get XX XX from machine || 99%
|-
| DA 00 04 05 || saved job count || 99%
|-
| DA 01 XX XX <VALUE> || response to DA 00 XX XX || 99%
|-
| A8 [[#VAL-ABSCOORD|<ABSCOORD>]] [[#VAL-ABSCOORD|<ABSCOORD>]] || Straight cut to absolute X Y; turn laser on with configured speed and power || 99%
|-
| A9 [[#VAL-RELCOORD|<RELCOORD>]] [[#VAL-RELCOORD|<RELCOORD>]] || Straight cut to relative X Y; turn laser on with configured speed and power || 99%
|-
| E7 50 [[#VAL-ABSCOORD|<ABSCOORD>]] [[#VAL-ABSCOORD|<ABSCOORD>]] || Bounding box top left? || 30%
|-
| E7 51 [[#VAL-ABSCOORD|<ABSCOORD>]] [[#VAL-ABSCOORD|<ABSCOORD>]] || Bounding box bottom right? || 30%
|-
| E8 02 E7 01 [[#VAL-CSTRING|<CSTRING>]] || Set filename for following transfer (transfer needs to be done really quickly after this!) || 90%
|-
| E8 01 XX XX || Read filename number XX XX ||
|-
| 88 [[#VAL-ABSCOORD|<ABSCOORD>]] [[#VAL-ABSCOORD|<ABSCOORD>]] || straight move to absolute X Y as fast as possible; with laser off || 99%
|-
| 89 [[#VAL-RELCOORD|<RELCOORD>]] [[#VAL-RELCOORD|<RELCOORD>]] || straight move to relative X Y as fast as possible; with laser off || 80%
|}