> For the complete documentation index, see [llms.txt](https://docs.smart-stuff.nl/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.smart-stuff.nl/p1-modbus-dongle/firmware-v1-legacy.md).

# FIRMWARE V1 — LEGACY

- [Firmware v1 overview](https://docs.smart-stuff.nl/p1-modbus-dongle/firmware-v1-legacy/firmware-v1.md): Information for older P1 Modbus adapters that still use legacy firmware v1.
- [Firmware v1 register mappings](https://docs.smart-stuff.nl/p1-modbus-dongle/firmware-v1-legacy/register-mapping.md): Legacy mapping reference for separately compiled firmware v1 variants.
- [Default P1 mapping](https://docs.smart-stuff.nl/p1-modbus-dongle/firmware-v1-legacy/register-mapping/default-p1-mapping.md): This is the normal P1 Modbus Dongle mapping from the non-emulation firmware.
- [Default float mapping](https://docs.smart-stuff.nl/p1-modbus-dongle/firmware-v1-legacy/register-mapping/default-float-mapping.md): This is the default FLOAT emulation mapping. It exposes a compact float-based layout.
- [ABB B21](https://docs.smart-stuff.nl/p1-modbus-dongle/firmware-v1-legacy/register-mapping/abb-b21.md): This mapping emulates the ABB B21 meter.
- [DTSU666 emulation](https://docs.smart-stuff.nl/p1-modbus-dongle/firmware-v1-legacy/register-mapping/dtsu666-emulation.md): This mapping emulates a DTSU666 style meter.
- [EM330 / EM340 emulation](https://docs.smart-stuff.nl/p1-modbus-dongle/firmware-v1-legacy/register-mapping/em330-em340-emulation.md): This mapping emulates an EM330/EM340 style meter.
- [Inepro / KLEFR 6924 emulation](https://docs.smart-stuff.nl/p1-modbus-dongle/firmware-v1-legacy/register-mapping/inepro-klefr-6924-emulation.md): This mapping emulates the KLEFR 6924 style layout.
- [Schneider Charge Pro emulation](https://docs.smart-stuff.nl/p1-modbus-dongle/firmware-v1-legacy/register-mapping/schneider-charge-pro-emulation.md): This mapping emulates the Schneider Charge Pro layout that is used for charger integrations.
- [SDM630 emulation](https://docs.smart-stuff.nl/p1-modbus-dongle/firmware-v1-legacy/register-mapping/sdm630-emulation.md): This mapping emulates an Eastron SDM630 style meter.
- [Migrate from v1 to v2](https://docs.smart-stuff.nl/p1-modbus-dongle/firmware-v1-legacy/migrate-to-v2.md): Upgrade an older P1 Modbus adapter from legacy firmware v1 to firmware v2.