/**
 * (c) 2026, Micro:bit Educational Foundation and contributors
 *
 * SPDX-License-Identifier: MIT
 */
/**
 * CDC pipeline saturation
 *
 * DAPLink's CDC serial path and WebUSB vendor serial reads share the same
 * UART ring buffer. After a physical USB connection, CDC consumes early
 * serial bytes before our vendor reads can get them, causing truncated
 * output. See: https://github.com/ARMmbed/DAPLink/issues/903
 *
 * Workaround: before flashing, push dummy data through the target's UART
 * to fill DAPLink's internal buffers. When nobody is reading from the CDC
 * serial port, the CDC TX buffer fills first, then cdc_process_event()
 * stops pulling from the UART RX ring buffer, and that fills too. Once
 * both are full, all subsequent UART data overflows harmlessly and
 * post-flash serial output is left for our vendor reads.
 *
 * V1 (nRF51) uses a Thumb blob for the legacy byte-at-a-time UART.
 * V2 (nRF52833) uses SWD register writes to trigger a UARTE DMA transfer.
 *
 * V1 DAPLink defaults to 9600 baud on fresh USB connection, so we call
 * setBaudrate(115200) before saturation to ensure DAPLink can decode the
 * bytes we send.
 */
import { BoardVersion } from "../device.js";
import { Logging } from "../logging.js";
import { type USBDeviceWrapper } from "./device-wrapper.js";
/**
 * Push dummy data through the target's UART to fill DAPLink's internal
 * CDC buffers, preventing CDC from consuming post-flash serial output.
 * Must be called while the target is halted.
 */
export declare function saturateCdcPipeline(device: USBDeviceWrapper, boardVersion: BoardVersion, logging: Logging): Promise<void>;