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  • Author Author: phoenixcomm
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NexGen: Hacking a Processor Select Panel - Part 2

phoenixcomm

imageThe Processor Select Panel, 7-F511F00121-1 (NSN: 1290-01-438-6575), is from an Apache Longbow AH-64D.

I only need 2 inputs and two outputs, as identified in the blog post "NexGen: Component Documentation: Panel, Processor Select". Just so we don't need page flipping here they are:

  1. Output: SWITCH, PROCESSOR - 1, SEL1, pin 6
  2. Output: SWITCH, PROCESSOR - 2, SEL2, Pin 7
  3. input: DISPLAY, ACTIVE PROCESSOR - 1, DAP1, pin *
  4. input: DISPLAY, ACTIVE PROCESSOR - 2, DAP2, pin * *pins are currently unknown.

pins 2 and 3 will go to an Arduino Mega interrupt pins 12 and 13 respectively.
Communications will be via SPI to CAN module.
meanwhile, CANaerospace will be doing the heavy lifting. where I will use an address from the reserved space 1300-1299

image

Service Responses
BYTE Data Type VALUES CHAN NOD IDS
BYTE 0 Node-ID (UCHAR)1 1300
0x514		 1300
0x514
BYTE 1 Data Type (UCHAR)2
BYTE 2 Service Code (*CHAR*)3 0
BYTE 3 Message Code (UCHAR)4
BYTE 4 Message Data STATUS 1001
BYTE 5 Message Data SEL1 & SEL2
BYTE 6 Message Data DAP1 0001
BYTE 7 Message Data DAP2 0001
BYTE5 DECODE 0xx0 bits 1 and 4 are pulled down = Auto Select Active
0xx1 = SEL1 Active
1xx0 = SEL2 Active
  1. node-ID: is in the range of 0-255 with node-ID “0” being the broadcast-ID referring to “all nodes”.
  2. Data Type: is in the range of 0-255 For data representation, the most commonly used basic data types are defined. This is the Data Type of the Message Data
  3. Service Code: is user-defined. This allows identification of each message by any receiving unit without the need for additional information.
  4. Message Code: For normal operation data (NOD) messages, the message code is incremented by one for each message and may be used to monitor the sequence of incoming messages. The message code then rolls over to zero after passing 255.

    The SPI/CAN module also will be using an interrupt on the Arduino pin 14. This notifies the Arduino that there is something waiting on the buffer, it could be a normal message or the Heartbeat. Below is a preliminary schematic.

    image