Add J1939 to RAMN and 'showcase mode'

[BenGardiner]

The PR is in 4 parts / commits:

1. refactor existing RAMN mission-time signals to prepare for adding J1939. There should be no change of functionality
2. add J1939 mission time signals
3. add J1939 diagnostics and DTCs
4. add a 'forced autopilot' that 1Hz randomizes command signals

Also added pytests that use python ctypes to call into firmware .c files recompiled for the host to verify the firmware serialization, diagnostic routing and diagnostic responses.

J1939 Signal Mapping and Refactoring (Commit c0f0999)

Added ENABLE_J1939_MODE to toggle between standard and J1939 modes. In J1939 mode, all existing vehicle control and status
signals were remapped to standard J1939 PGNs using 29-bit identifiers (Extended ID).

• Key Signal Mappings:
  • TSC1 (PGN 0): Torque/Speed Control (Accelerator Commands).
  • XBR (PGN 1024): External Brake Request (Brake Commands).
  • EEC1/EEC2 (PGN 61444/61443): Engine Speed (RPM) and electronic engine control status.
  • EBC1 (PGN 61441): Electronic Brake Controller status.
  • ETC2 (PGN 61445): Transmission Control status.
  • VDC2 (PGN 61449): Vehicle Dynamic Stability Control (Steering).

J1939 Diagnostic Support (Commit 8d0117d)

• UDS over J1939: Implemented ISO 14229 (UDS) diagnostics encapsulated within J1939 PDU1 (Physical, PGN 0xDA00) and PDU2 (Functional, PGN 0xDB00) frames.
• KWP2000 and XCP at PGN 0xEF PropA ; filtering by source address.
• Active DTCs (DM1): Implemented the J1939 DM1 (Active Diagnostic Trouble Codes) message.
  • Single DTC: Sent as a standard 8-byte message (PGN 65226).
  • Multiple DTCs: Automatically utilizes the J1939 Transport Protocol (TP) with Broadcast Announce Message (BAM) to transmit more than one active trouble code.
• Network Management: Added support for J1939 Address Claiming (PGN 0xEE00), allowing each ECU to claim a unique source address on the bus (e.g., Headway Control:
  42, Steering: 19, Powertrain: 90, Body: 33).
• ECU Identification: Implemented PGN 64965 (ECU ID) responses via BAM TP for multi-packet identification strings.

[github-actions]

🔨 Build & Macro Coverage Report

Default Builds — Hex File Sizes

ECU	Debug (tag 15.0)	Release (tag 15.0)
ECUA	530 KiB (543274 bytes)	358 KiB (367050 bytes)
ECUB	339 KiB (347311 bytes)	198 KiB (202935 bytes)
ECUC	319 KiB (327437 bytes)	177 KiB (182054 bytes)
ECUD	329 KiB (337435 bytes)	184 KiB (189194 bytes)

Macro Coverage Build Results

Variant	Macros Changed	Result	Warnings
gsusb	+ENABLE_GSUSB −ENABLE_CDC	✅ Pass	0
gsusb_and_bb	+ENABLE_GSUSB +ENABLE_BITBANG	✅ Pass	0
i2c	+ENABLE_I2C	✅ Pass	0
j1939	+ENABLE_J1939_MODE	✅ Pass	0
j1939_showcase_mode	+ENABLE_J1939_MODE +RAMN_SHOWCASE_MODE	✅ Pass	0
kwp	+ENABLE_KWP	✅ Pass	0
no_debug	−ENABLE_USB_DEBUG −ENABLE_JOYSTICK_CONTROLS −ENABLE_SCREEN −ENABLE_CHIP8 −GENERATE_RUNTIME_STATS	✅ Pass	0
no_dynamic_bitrate	−ENABLE_DYNAMIC_BITRATE	✅ Pass	0
no_extras	−ENABLE_J1979 −ENABLE_MINICTF −ENABLE_CHIP8 −ENABLE_SCREEN −ENABLE_SPI	✅ Pass	0
no_uds	−ENABLE_UDS −ENABLE_UDS_REPROGRAMMING	✅ Pass	12
uart	+ENABLE_UART −ENABLE_CDC −ENABLE_USB	✅ Pass	13
usb_autodetect	+ENABLE_USB_AUTODETECT	✅ Pass	0
watchdog	+WATCHDOG_ENABLE	✅ Pass	0

Source Code Compile Coverage

• Total .c source lines: 21260
• Lines compiled in ≥1 configuration: 19915 (~94%)
• ENABLE_ macro coverage: 23/23 (100.0%) macros tested in both ON and OFF states

Full ENABLE_ Macro Coverage Table

#	Macro	Tested ON	Tested OFF	Covered
1	ENABLE_ADC	default (ECUB, ECUC, ECUD)	default (ECUA)	✅
2	ENABLE_BITBANG	default (ECUA), variant: gsusb_and_bb	default (ECUB, ECUC, ECUD)	✅
3	ENABLE_CDC	default (ECUA)	default (ECUB, ECUC, ECUD), variant: gsusb, variant: uart	✅
4	ENABLE_CHIP8	default (ECUA)	default (ECUB, ECUC, ECUD), variant: no_debug, variant: no_extras	✅
5	ENABLE_DYNAMIC_BITRATE	default (ECUA, ECUB, ECUC, ECUD)	variant: no_dynamic_bitrate	✅
6	ENABLE_GSUSB	variant: gsusb, variant: gsusb_and_bb	default (ECUA, ECUB, ECUC, ECUD)	✅
7	ENABLE_I2C	variant: i2c	default (ECUA, ECUB, ECUC, ECUD)	✅
8	ENABLE_J1939_MODE	variant: j1939, variant: j1939_showcase_mode	default (ECUA, ECUB, ECUC, ECUD)	✅
9	ENABLE_J1979	default (ECUA, ECUB, ECUC, ECUD)	variant: no_extras	✅
10	ENABLE_JOYSTICK_CONTROLS	default (ECUA)	default (ECUB, ECUC, ECUD), variant: no_debug	✅
11	ENABLE_KWP	variant: kwp	default (ECUA, ECUB, ECUC, ECUD)	✅
12	ENABLE_MINICTF	default (ECUA, ECUD)	default (ECUB, ECUC), variant: no_extras	✅
13	ENABLE_SCREEN	default (ECUA)	default (ECUB, ECUC, ECUD), variant: no_debug, variant: no_extras	✅
14	ENABLE_SPI	default (ECUA, ECUD)	default (ECUB, ECUC), variant: no_extras	✅
15	ENABLE_UART	variant: uart	default (ECUA, ECUB, ECUC, ECUD)	✅
16	ENABLE_UDS	default (ECUA, ECUB, ECUC, ECUD)	variant: no_uds	✅
17	ENABLE_UDS_REPROGRAMMING	default (ECUA, ECUB, ECUC, ECUD)	variant: no_uds	✅
18	ENABLE_USB	default (ECUA)	default (ECUB, ECUC, ECUD), variant: uart	✅
19	ENABLE_USB_AUTODETECT	variant: usb_autodetect	default (ECUA, ECUB, ECUC, ECUD)	✅
20	ENABLE_USB_DEBUG	default (ECUA)	default (ECUB, ECUC, ECUD), variant: no_debug	✅
21	ENABLE_XCP	default (ECUB, ECUC, ECUD)	default (ECUA)	✅
22	GENERATE_RUNTIME_STATS	default (ECUA, ECUB, ECUC, ECUD)	variant: no_debug	✅
23	WATCHDOG_ENABLE	variant: watchdog	default (ECUA, ECUB, ECUC, ECUD)	✅

[BenGardiner]

@CamilleTTT

• I have moved the J1939 code to ramn_j1939.c as it should have been instead of ramn_customize.
• I have renamed the force autopilot stuff to 'showcase mode'

Please merge #47 first, then I will rebase and tweak this one to create j1939 and j1939_showcase variants on top of it