Changelog

All notable hardware changes to LinHT are documented in this file. The project uses board revisions instead of semantic versioning.

Unreleased - Revision C

Current main; board date 2026-07-10. This revision applies corrections found while testing Revision B.

Isolated the side button voltage domains: the ATtiny826 reads the physical button and drives the 1.8 V SoM input as open-drain.
Connected the TLV320AIC3100 reset input to SoM GPIO pin 110.
Replaced the 12.288 MHz audio oscillator with a 12 MHz ECS-2520MV oscillator and removed the codec MCLK connection to the SoM.
Replaced obsolete inductors with SRN6028C-4R7M and 0402HP-20NXGRW.
Replaced the on-board GNSS chip antenna with a TE 1909763-1 U.FL-class connector for an external antenna.
Added thermal relief to small ground-connected footprints and resolved PCB DRC errors and warnings.

Added a GRF5604 RF power amplifier and SKY13330-397LF RF switch.
Added two PE4312C-Z digital step attenuators to the RF input path.
Added the Quectel LG77LICMD GNSS receiver with an ANT8010LL05R1516A chip antenna.
Added USB-C battery charging based on BQ25792RQMR, including a battery PPTC fuse and thermistor interface.
Added an ATtiny826 power-management controller and changed the 5 V converter to TPS565242DRLR.

Replaced the WM8960 audio codec with TLV320AIC3100IRHBR and added a dedicated 1.8 V I/O supply.
Updated the PCB layout, grounding, component metadata, fabrication outputs, and panelization for prototype manufacturing.

Built four proof-of-concept prototypes around the MCM-iMX93 SoM and SX1255 direct-IQ RF front-end.
Validated Linux boot, USB development access, display integration, and the initial SDR and DSP architecture.