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projects:crazyflie:firmware:comm_protocol [2012-08-13 22:28]
macke 		projects:crazyflie:firmware:comm_protocol [2013-08-23 19:54]
ledvinap
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 ====== Overview ====== ====== Overview ======
-===== CRTP ===== +CRTP is the protocol used to communicate with Crazyflie. Is originally stands for //Crazy RealTime Protocol//. The protocol permits to communicate independently with the copter subsystem and would have the capability to handle packet priorities. 
-The CRTP (Crazy RealTime Protocol) is the name of the protocol used to communication with the Crazyflie. The protocol is used for multiple physical layers: + 
-  * [[comm_protocol#serial_port | UART]] +CRTP is implemented in 3 layers: 
-  * [[comm_protocol#usb_port | USB]] + 
-  * [[comm_protocol#2.4_GHz_NordicSemi_Radio | 2.4 GHz NordicSemi Radio]] +<ditaa> 
-  * ...+ +-----------------------+ 
 + |   Application/ports   | 
 + +-----------------------+ 
 + | CRTP packets handling | 
 + +-----------------------+   
 + |       CRTP Link       | 
 + +-----------------------+ 
 +</ditaa> 
 + 
 +  * **CRTP Link** is responsible for transferring the packets between the copter and the PC. It will typically handles packet size and error detection. 
 +  * **CRTP Packet handling** delivers the packet to the right subsystem in the copter and in the PC control software. 
 +  * **Application/ports** represents the subsystems that sends and receives messages. 
 + 
 +Implemented link drivers: 
 +^ **Link**                                           ^                                             ^ 
 +| [[comm_protocol#serial_port | UART]]               | Uart link, mainly used in early development | 
 +| [[comm_protocol#usb_port | USB]]                   | To be implemented USB link. (Crazyflie USB port) | 
 +| [[comm_protocol#2.4_GHz_NordicSemi_Radio | radio]] | 2.4 GHz NordicSemi Radio link (any nRF24L01 compatible radio, eg. Crazyradio dongle) | 
 + 
 +Current port allocation: 
 +^  **Port**  ^   **Target**   ^  **Used for**   ^ 
 +|   0        |   [[projects:crazyflie:firmware:console | Console ]]      | Read console text that is printed to the console on the Crazyflie using consoleprintf | 
 +|   2        |   [[projects:crazyflie:firmware:param | Parameters]]   | Get/set parameters from the Crazyflie. Parameters are defined using a macro in the Crazyflie source-code | 
 +|   3        |   [[projects:crazyflie:crtp:commander |Commander]]    | Sending control set-points for the roll/pitch/yaw/thrust regulators | 
 +|   5        |   [[projects:crazyflie:firmware:log#communication_protocol|Log]]    | Set up log blocks with variables that will be sent back to the Crazyflie at a specified period. Log variables are defined using a macro in the Crazyflie source-code | 
 +|   14       |   [[projects:crazyflie:pc_utils:debugdriver|Client-side debugging]]    | Debugging the UI and exists only in the Crazyflie Python API and not in the Crazyflie itself.  | 
 +|   15       |   [[projects:crazyflie:firmware:linklayer |Link layer ]]   | Used to control and query the communication link |
  
 ====== Communication ====== ====== Communication ======
Line 13: Line 39:
   7   6   5   4   3   2   1   0   7   6   5   4   3   2   1   0
 +---+---+---+---+---+---+---+---+ +---+---+---+---+---+---+---+---+
-| R |     Port      |  Channel  |+|     Port      |  Res. | Chan. | 
 +---+---+---+---+---+---+---+---+ +---+---+---+---+---+---+---+---+
 |            DATA 0             | |            DATA 0             |
Line 21: Line 47:
 |            DATA 30            | |            DATA 30            |
 +---+---+---+---+---+---+---+---+ +---+---+---+---+---+---+---+---+
- 
-+--------+--------+--------+--------+--------+--....--+--------+ 
-|  0xAA  |  0xAA  | Header | Length | Data0  | Packet | CRC32  | 
-+--------+--------+--------+--------+--------+--....--+--------+ 
  
 </code> </code>
 ^ **Field** ^ **Byte** ^ **Bit** ^   **Description**      ^ ^ **Field** ^ **Byte** ^ **Bit** ^   **Description**      ^
-|   Header  |     0    |   0-2   | The destination channel  | +|   Header  |     0    |   0-1   | The destination channel  | 
-|    :::    |     0    |   3-6   | The destination port  | +|    :::    |     0    |   2-3   | Reserved for transport layer  | 
-|    :::    |     0    |    7    | Resend flag. If R=1 the last packet needs to be resent  |+|    :::    |     0    |   4-7   | The destination port  |
 |    Data   |    1-31  |         | The data in the packet | |    Data   |    1-31  |         | The data in the packet |
  
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 ==== 2.4 GHz NordicSemi Radio ==== ==== 2.4 GHz NordicSemi Radio ====
-The wireless interface will add additional header data like CRC when sending the packet and therefore the packet sent to the wireless interface is only a CRTP packet.+The wireless interface will add additional header data like CRC when sending the packet and therefore the packet sent to the wireless interface is only a CRTP packet (header and data).
  
 ==== USB port ==== ==== USB port ====
Line 45: Line 67:
  
 ==== Serial port ==== ==== Serial port ====
 +The serial port is configured in 115200 8N1. CRTP packets are sent and received asynchronously using the following packet format:
 +
 <code> <code>
   7   6   5   4   3   2   1   0   7   6   5   4   3   2   1   0
Line 52: Line 76:
 |             0xAA              | |             0xAA              |
 +---+---+---+---+---+---+---+---+ +---+---+---+---+---+---+---+---+
-| R |     Port      |  Channel  |+|      Port     |  Res  | Chan. |
 +---+---+---+---+---+---+---+---+ +---+---+---+---+---+---+---+---+
 |         Packet length         | |         Packet length         |
Line 62: Line 86:
 |            DATA 30            | |            DATA 30            |
 +---+---+---+---+---+---+---+---+ +---+---+---+---+---+---+---+---+
-|              CRC              |+|            Cksum              |
 +---+---+---+---+---+---+---+---+ +---+---+---+---+---+---+---+---+
  
 +--------+--------+--------+--------+--------+--....--+--------+ +--------+--------+--------+--------+--------+--....--+--------+
-|  0xAA  |  0xAA  | Header | Length | Data0  | Packet | CRC32  |+|  0xAA  |  0xAA  | Header | Length | Data0  | Packet | Cksum  |
 +--------+--------+--------+--------+--------+--....--+--------+ +--------+--------+--------+--------+--------+--....--+--------+
  
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 ^ **Field** ^ **Byte** ^ **Bit** ^     **Description**     ^ ^ **Field** ^ **Byte** ^ **Bit** ^     **Description**     ^
 |   Start   |    0-1   |   0-2   | Start token for synchronization (0xAAAA)  | |   Start   |    0-1   |   0-2   | Start token for synchronization (0xAAAA)  |
-|   Header  |     2    |   0-2   | The destination channel  | +|   Header  |     2    |   0-1   | The destination channel  | 
-|    :::    |     2    |   3-6   | The destination port  | +|    :::    |     2    |   2-3   | Reserved for the link layer | 
-|    :::    |     2    |    7    | Resend flag. If R=1 the last packet needs to be resent  | +|    :::    |     2    |   4-7   | The destination port  | 
-|    Size   |     3    |         | The size of the packet | +|    Size   |     3    |         | Number of data byte | 
-|    Data   |    4-34  |         | The data in the packet | +|    Data   |    4-..  |         | The data in the packet | 
-|    CRC    |   35-36  |         | The CRC16 of the packet |+|   Cksum   |  4+size  |         | Checksum. Sum of all the bytes, excluding //Start//, modulo 256. |
  
-===== Ports ===== +=== Examples === 
-The following ports are used during the communication. +To send setpoints to the [[projects:crazyflie:crtp:commander|commander]] send:  
-^                 **Port**                  ^   **Target**   ^ +<code> 
-|   [[comm_protocol#console|0]]             |   Console      | +0xaa 0xaa 0x30 0x0e 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x3e 
-|   [[comm_protocol#logging|5]]             |   Logging      | +</code>
-|   [[comm_protocol#parameters|9]]          |   Parameters   | +
-|   [[comm_protocol#flight_control|13]]     | Flight control | +
-|   [[comm_protocol#link_layer|15]]         |   Link layer   | +
- +
-==== Console ==== +
-This port is used as a one-way text console. Printouts using printf will be sent on this port and can be read by a receiver if connected.+
  
 +To ping Crazyflie:
 <code> <code>
-  7   6   5   4   3   2   1   0 + ->   0xaa 0xaa 0xf0 0x01 0x01 0xf2     # Sent to the copter  
-+---+---+---+---+---+---+---+---+ + <-   0xaa 0xaa 0xf0 0x01 0x01 0xf2     # Received from the copter
-|             CHAR 0            | +
-+---+---+---+---+---+---+---+---+ +
-:   :   :   :   :   :   :   :   : +
-+---+---+---+---+---+---+---+---+ +
-|             CHAR 30           | +
-+---+---+---+---+---+---+---+---+ +
- +
-+--------+--------+--------+--------+--------+--....--+--------+ +
-|  0xAA  |  0xAA  | Header | Length | Data0  |        | Data30 | +
-+--------+--------+--------+--------+--------+--....--+--------+ +
 </code> </code>
- +===== Ports =====
-The contents of the buffer on the copter side is sent if any of the following is fulfulled: +
-  * The output buffer (of 31 bytes) is full +
-  * A "newline" character has to be send (\n and/or \r) +
-  * A flush command as been issued+
  
 ==== Logging ==== ==== Logging ====
Line 131: Line 135:
  
 The following messages are sent from the Client to the Crazyflie: The following messages are sent from the Client to the Crazyflie:
-^  **Command byte**  ^  **Description**  ^ +^  **Request for**  ^  **Byte**  ^  **Description**  ^ 
-|         0          | Resets the TOC index pointer in the Crazyflie  | +| TOC item  |     0      | 0x00 to identify the command  | 
-|         1          | Request the next item in the TOC               | +|   :::    |     1      | The index of the TOC item to request | 
-|         3          | Request the CRC32 of the TOC |+|  TOC CRC and count |  0   | 0x01 Request the TOC CRC and item count |
  
 The following messages are sent from the Crazyflie to the Client: The following messages are sent from the Crazyflie to the Client:
-^  **Command byte**  ^  **Byte**  ^  **Description**  ^ +^  **Reply for**  ^  **Byte**  ^  **Description**  ^ 
-|       0 or 1       |     0      | The two command bytes has the same format but the command byte 0 indicates that it is the last item in the TOC  | +|     TOC item       |     0      | 0x00 to identify the command | 
-|        :::         |     1      | Variable ID  | +|        :::         |     1      | The ID of the next variable to fetch. If ID == 0xFF no more items are available. | 
-|        :::         |     2      | Type (ref to variable type?)  | +|        :::         |     2      | Variable ID  | 
-|        :::         |    3-n     | Null terminated string containing group name  |+|        :::         |     3      | Type (ref to variable type?)  | 
 +|        :::         |    4-n     | Null terminated string containing group name  |
 |        :::         |    n-m     | Null terminated string containing variable name  | |        :::         |    n-m     | Null terminated string containing variable name  |
-|         3          |     0      | The TOC CRC32 command byte  |+| TOC CRC and count  |     0      | 0x01 to identify the command  |
 |        :::         |     1      | Number of total variables in TOC  | |        :::         |     1      | Number of total variables in TOC  |
-|        :::         |    2-5     | CRC32 value of the TOC (of what exacly? group/names?)  | +|        :::         |    2-5     | CRC32 value of the TOC (calculated from raw contents of log TOC section)  |
- +
-<code> +
-Bytes     1       1          1    Null terminated strings +
-        +---+------------+------+----------+--------------+ +
-        | 0 |            |      |          |              | +
-        +---+   Var ID   | Type |  Group   |     Name     | +
-        | 1 |            |      |          |              | +
-        +---+------------+------+---+------+--------------+ +
-        | 3 | Num. Vars  |  CRC32   | +
-        +---+------------+----------+ +
-Bytes     1       1           4 +
-</code>+
  
 == Usage == == Usage ==
Line 173: Line 166:
    Computer                 Crazyflie    Computer                 Crazyflie
    --------                 ---------    --------                 ---------
-Reset TOC pointer  --->  [Pointer resets] +Request for TOC item --->   
-Get next element   ---> +with ID omitted 
-                   <--- TOC element +                     <---  First TOC element (including ID of next element) 
-                   .... +Request for TOC item ---> 
-                   .... +                     <--- Requested TOC element (including ID of next element) 
-Get next element   ---> +                     .... 
-                   <--- TOC element +                     .... 
-Get next element   ---> +Request for TOC item ---> 
-                   <--- Last TOC element+                     <--- Requested TOC element (no more items, return next index 0xFF)
 [Fetch complete]                    [Fetch complete]                   
 </code> </code>
Line 189: Line 182:
 == Messages == == Messages ==
 The following messages are sent from the Client to the Crazyflie: The following messages are sent from the Client to the Crazyflie:
-^  **Command byte**  ^  **Byte**  ^  **Description**  ^ +^  **Request for**  ^  **Byte**  ^  **Description**  ^ 
-|         0          |     0      | Add a logging block  |+|  Adding a new log  |     0      | 0x00 for identifying the command to add a logging block  |
 |        :::         |     1      | Desired block id  | |        :::         |     1      | Desired block id  |
 |        :::         |     2      | Period in 10th of ms | |        :::         |     2      | Period in 10th of ms |
 |        :::         |    3-31    | [[comm_protocol#variable_format|Variables to log]]  | |        :::         |    3-31    | [[comm_protocol#variable_format|Variables to log]]  |
-|         1          |     0      | Append logging variables to an existing block  |+|  Append to log     |     0      | 0x01 for identifying the command to append logging variables to an existing block  |
 |        :::         |     1      | Block ID | |        :::         |     1      | Block ID |
 |        :::         |    2-31    | [[comm_protocol#variable_format|Variables to log]]  | |        :::         |    2-31    | [[comm_protocol#variable_format|Variables to log]]  |
-|         2          |     0      | Delete an existing block  |+|  Delete a log      |     0      | 0x02 to identify the command for delete an existing block  |
 |        :::         |     1      | Block ID | |        :::         |     1      | Block ID |
-|         3          |     0      | Enable logging data from an existing block  |+|  Enable a log      |     0      | 0x03 to identify the command for enabling logging data from an existing block  |
 |        :::         |     1      | Block ID | |        :::         |     1      | Block ID |
-|         4          |     0      | Disable logging data from an existing block  |+|  Disable a log     |     0      | 0x04 to identify the command for disablling logging data from an existing block  |
 |        :::         |     1      | Block ID | |        :::         |     1      | Block ID |
  
Line 348: Line 341:
 **TODO** **TODO**
  
-=== Link layter ===+=== Link layer ===
 | 3:15:0                                    | Echo (profiling)  | | 3:15:0                                    | Echo (profiling)  |
 | 3:15:1                                    | Source (profiling)| | 3:15:1                                    | Source (profiling)|
 | 3:15:2                                    | Sink (profiling)  | | 3:15:2                                    | Sink (profiling)  |
 | 3:15:3                                    | NULL packet       | | 3:15:3                                    | NULL packet       |
projects/crazyflie/firmware/comm_protocol.txt · Last modified: 2021-06-24 16:49 by kimberly

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