Topics

Attendance

• Jane Brandenburg - PHS
• Allen Brown - Scalawags
• Doug Edmonds - PHS
• Terry Heath - PHS
• Sean Lavelle - CHS
• Gary Oliver - Scalawags
• Jeff Rice - Scalawags
• Asumu Takikawa - CV

We continued to beat on the state diagrams. We then did a function breakdown, based mostly on the diagrams.

Packet Definition

Changes made to the table above:

• Dest moved to before Src. This is so the packet can be forwarded sooner.
• CKSUM moved after End. Makes state machine easier to write.
• Commands defn more clearly deferred to the command table.

Command Table

E50000

For example, if the packet was:

$12D51A02122059\n

• $ - Start Packet
• 2 - Node 2, the manifold, is to receive this packet.
• 1 - Node 1, the LinkSys, sends this packet.
• E - This is a PERIODIC message type.
• 5 - PERIODIC message slot 5.
• 1A - Time period in hexadecimal milliseconds. 26ms.
• 02 - Length
• 1220 - Data to be packetized and executed periodically.
  • 1 - Node 1, the LinkSys, sends this packet.
  • 2 - Node 2, the manifold, is to receive this packet.
  • 2 - READ message.
  • 0 - Port 0.
• \n - End Packet.
• 59 - Checksum. (I didn't really calculate the checksum here.)

Changes made to the table above:

• LOG and ERROR commands merged into the LOG command. Additional field added to distinguish between them.
• ADDR field removed from LOG/ERROR command.

Jeff's picture of the Packet Parsing state diagram:

Asumu's picture of the Command Parsing state diagram:

Sean's list of function definitions:

Function list:

• void commands(char *packetPayloadSrc)
• char * command(char *packetPayload)
• int address(char *packetPayload)
• int data(char *packetPayload)
• int time(char *packetPayload)
• int length(char *packetPayload)
• enum charClassifier(char)
• void write(src, addr, data)
• void read(src, addr)
• configWr(src, addr, data)
• configRd(src, addr)
• error(src, level, length, char *packetPayload)
• charClassifier() uses enum {hex, start, end, ignore}

Deferred functions:

• dataIs()
• configDataIs()
• periodic()

Packet structure and pointers:

This ASCII diagram naturally has to be viewed with a monospaced font.

                  The commands() function gets passed a pointer to here. (char *packetPayloadSrc)
                  //============================================================================
                  ||
                  ||
                  ||    The command() function gets passed a pointer to here. (char *packetPayload)
                  ||    //========================================================================
                  ||    ||
                  ||    ||                       Replaced with a null
                  ||    ||                       //====================
                  ||    ||                       ||
                  ||    ||                       ||
                 \\//  \\//                     \\//
                  \/    \/                       \/
    /-|-|-|-|-|-|-|----------------------------|-|-|-|-|-|-|-\
    | Start | Dest| Src |   Payload commands   | End | Cksum |
    \-|-|-|-|-|-|-|----------------------------|-|-|-|-|-|-|-/
  

The sections of the packet with |-|-|-| are the sections that have been stripped out before the commands() function gets ahold of the packet.

Action Items from last week

• Determine breaker reset time. -- design to 2 sec

Action Items before next week

• Email copy of BNF for the protocol to Allen. -- Asumu
• Email state diagram for the command parser to Allen. -- Asumu
• Email the state diagrams for the packet parser and the CRC checker to Allen. -- Jeff
• Determine breaker reset time. -- design to 2 sec
• Logins to scalawags.org. -- Gary

Schedule

• Oct 7 - location: Corvallis High School
  • Define the tests for each module.
  • Assign coding for the various modules.
  • Consider queueing.
• Oct 14 - location: Corvallis High School
  • Code Reviews.
  • Discuss how to optimize FRC code.
• Oct 21 - location: ?
  • Code Reviews.
  • Optimize FRC code.
  • What filesystems on laptop?
• Oct 28 - location: ?
  • Code Reviews.
  • Optimize FRC code.