In 2026-04, delivered a critical DMA TCD pool alignment bug fix for the Zephyr project (Zephyr4Microchip/zephyr). By changing DTCM sections from SUBALIGN(4) to ALIGN(4), individual DMA TCD objects now maintain their own alignment requirements, preventing assertion failures in EDMA_TcdSetTransferConfig and addressing a regression previously observed with a 32-byte aligned dma_tcdpool. Commit de3deb75d44d6ceea24e69b2336da2fea768ab02; Fixes: #107058. This work improves runtime reliability of DMA transfers and reduces risk of critical transfer-path failures.

March 2026 monthly summary for the renesas/zephyr repository. Focused on strengthening UART reliability and cross-device compatibility by delivering SERCOM revision-aware improvements to the SAM0 UART driver, and aligning error handling with SERCOM revisions. The work reinforces device support and reduces risk in production deployments by ensuring proper interrupt handling and configuration of transmission caches across SERCOM variants.

September 2025 Monthly Summary — zephyrproject-rtos/zephyr-testing Overview: - Delivered SAMC21 DAC support in Zephyr, enabling analog output features on SAMC21-based boards and expanding hardware coverage for the SAM0 family. Key features delivered: - SAMC21 DAC support added: device tree entry for the DAC peripheral, including memory map, interrupts, and clock configuration. - SAMC21-specific SYNCBUSY handling implemented via conditional compilation to ensure proper initialization and enablement of the DAC driver. Major bugs fixed: - Resolved SAMC21 DAC initialization differences by introducing SOC-specific guards for the SYNCBUSY register, reducing startup issues on affected revisions. Overall impact and accomplishments: - Enables Zephyr to support DAC on SAMC21, unlocking new use cases and accelerating prototyping for SAMC21-based designs. - Improves cross-SOC compatibility and reduces maintenance burden when supporting hardware revisions across the SAM0 family. Technologies/skills demonstrated: - Device tree integration for new peripherals - Hardware register mapping and memory configuration - Conditional compilation for SOC-specific revisions - Cross-SOC driver development and kernel integration - Code review and sign-off discipline

April 2025—AmbiqMicro/ambiqzephyr: Focused on stabilizing UART serial communication under Zephyr's microsecond timeout model. Implemented a critical bug fix in the uart_sam0 driver to correct asynchronous RX timeout calculation, aligning with Zephyr's updated timeout representation and eliminating timing inaccuracies. This change improves reliability of UART-based features across products and reduces intermittent timeout failures in production.