forked from jappel/VersaMCU
Julian Appel
f60a29137c
Hardware-tested the UF2 bootloader end to end on a real VersaPad v2 board. Found and fixed a real bug: the bootloader's jump into the app (__set_MSP -> SCB->VTOR -> bx) hard-faulted on every standalone boot, even with the debugger fully disconnected; identical register/VTOR values injected directly by a halted debugger ran fine, which pointed at the missing __DSB()/__ISB() barriers ARM's own guidance requires for this exact pattern. Also fixed a USB PID collision (0x0011 is Adafruit's own Gemma M0 bootloader PID, misidentified by Windows as a Circuit Playground COM port instead of exposing VERSABOOT). This board has no dedicated reset/boot button, so add a hardware boot entry that doesn't need one: holding the bottom-right Cherry MX key (key_id 24) during reset/power-on drives its matrix row and reads its column directly in the bootloader, before the app is even validated. Also corrected the app-side flash_with_bootloader.ld (was missing the NVM carve-out flash_without_bootloader.ld already has) and boards/versapad.json (wrong flash/RAM size, wrong MCU macro, stale PID), and enabled the previously-commented-out env:versapad_usb. Documented findings in bootloader/README.md, bootloader/TESTING.md, and doc/09_known_limitations.md. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
35 lines
854 B
JSON
35 lines
854 B
JSON
{
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"build": {
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"arduino": {
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"ldscript": "flash_with_bootloader.ld",
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"variant": "versapad"
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},
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"core": "arduino",
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"variant": "versapad",
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"cpu": "cortex-m0plus",
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"extra_flags": "-DARDUINO_SAMD_ZERO -DARM_MATH_CM0PLUS -D__SAMD21G18A__",
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"f_cpu": "48000000L",
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"hwids": [
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["0x239A", "0x0042"]
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],
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"mcu": "samd21g17d",
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"usb_product": "VersaPad v2",
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"usb_manufacturer": "Custom"
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},
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"connectivity": ["usb"],
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"frameworks": ["arduino"],
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"name": "VersaPad v2 (USB bootloader)",
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"upload": {
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"maximum_ram_size": 16384,
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"maximum_size": 120832,
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"disable_flushing": true,
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"native_usb": true,
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"offset": "0x2000",
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"protocol": "sam-ba",
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"require_upload_port": true,
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"use_1200bps_touch": true,
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"wait_for_upload_port": true
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},
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"url": "",
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"vendor": "Custom"
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}
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