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Packet Trace: Schedule Write

This document details the complex operation of writing a schedule to the pump.

Overview

Writing a schedule involves: 1. Large Payload: A full schedule layer is 42 bytes. 2. Packet Splitting: BLE limits mean we must split the 59-byte command into 3 writes. 3. Class 10 SET: Using OpSpec 0xB3 (SET with long payload).

1. Schedule Data Structure

A schedule layer consists of 7 days (Monday-Sunday), 6 bytes per day.

Total Size: 7 * 6 = 42 bytes.

Day Format (6 bytes): 

[Enabled] [Action] [Start-H] [Start-M] [End-H] [End-M]
- Enabled: 0x01 (Yes) or 0x00 (No) - Action: 0x01 (Start/Run) or 0x00 (Stop) - Time: Hours (0-23) and Minutes (0-59)

Example Schedule

  • Monday: Run 06:30 to 08:30
  • Other Days: Disabled

Monday Bytes: 

01 01 06 1E 08 1E
- 01: Enabled - 01: Action (Run) - 06 1E: Start 06:30 - 08 1E: End 08:30

Payload (42 bytes): 

01 01 06 1E 08 1E (Mon)
00 00 00 00 00 00 (Tue)
00 00 00 00 00 00 (Wed)
... (Thu-Sun)

2. Build Command

Target: - Sub ID: 1000 (0x03E8) - Layer 0 - Obj ID: 84 (0x0054) - Schedule

Header Structure: 

[Start] [Length] [Dest] [Src] [Class] [OpSpec] [Sub-H] [Sub-L] [Obj-H] [Obj-L] ...

OpSpec: - SET (Long): 0xB3

Type Header (Specific to Object 84): - Before the data, we need a 3-byte type header and 2-byte size. - 00 DA 01 (Type 218) - 00 2A (Size 42 bytes)

Full Packet Construction (59 bytes):

Section Bytes Value Description
Header 0-3 27 3B E7 F8 Req, Len 59, Dest, Src
APDU 4-5 0A B3 Class 10, OpSpec SET
IDs 6-9 00 54 03 E8 Obj 84, Sub 1000
Type 10-12 00 DA 01 Type Header
Size 13-14 00 2A Data Size (42)
Data 15-56 01 01 ... 42 bytes of schedule
CRC 57-58 XX XX CRC-16

3. BLE Packet Splitting

The 59-byte packet cannot be sent in one go. It must be split into 20-byte chunks.

Chunk 1 (Bytes 0-19)

27 3B E7 F8 0A B3 00 54 03 E8 00 DA 01 00 2A 01 01 06 1E 08

Chunk 2 (Bytes 20-39)

1E 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

Chunk 3 (Bytes 40-58)

00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 XX XX

Sending Sequence

  1. Write Chunk 1
  2. Wait 10ms (Critical!)
  3. Write Chunk 2
  4. Wait 10ms
  5. Write Chunk 3

4. Response

The pump reassembles the chunks and, if valid, sends an acknowledgment.

24 0A 20 E7 0A 34 00 54 03 E8 XX XX

Breakdown: - 24: Response - 34: OpSpec (SET Response) - 00 54: Obj ID - 03 E8: Sub ID - Success!

5. Common Pitfalls

  1. No Splitting: Sending 59 bytes at once will be ignored by the pump.
  2. No Delays: Sending chunks too fast will overflow the pump's buffer.
  3. Wrong Length: The length byte in Chunk 1 must be 0x3B (59), describing the total packet, not just the chunk.
  4. CRC: Calculated over the full 59 bytes.

6. Verification

After writing, read back the schedule to verify.

Read Request: 

27 0D E7 F8 0A 03 00 54 03 E8 00 XX XX

Response: Should contain the same 42 bytes of data.