Add fixed-point support for setting center frequency and sample rate. (3/n)

firmware/common/fpga.h

@@ -26,6 +26,14 @@
 
 #include "ice40_spi.h"
 
+/* Supported Bitstreams. */
+typedef enum {
+	FPGA_BITSTREAM_STANDARD = 0,
+	FPGA_BITSTREAM_HALFPREC = 1,
+	FPGA_BITSTREAM_EXTPREC_RX = 2,
+	FPGA_BITSTREAM_EXTPREC_TX = 3,
+} fpga_bitstream_index_t;
+
 /* Up to 7 registers, each containing up to 8 bits of data */
 #define FPGA_NUM_REGS            7
 #define FPGA_DATA_REGS_MAX_VALUE 255

firmware/common/radio.c

@@ -59,13 +59,19 @@ void radio_init(radio_t* const radio)
 	radio->config[RADIO_BANK_TX][RADIO_OPMODE] = TRANSCEIVER_MODE_TX;
 	radio->config[RADIO_BANK_IDLE][RADIO_BIAS_TEE] = false;
 	radio->regs_dirty = 0;
+	radio->regs_locked = 0;
 }
 
 static inline void mark_dirty(radio_t* const radio, radio_register_t reg)
 {
 	radio->regs_dirty |= (1 << reg);
 }
 
+static inline bool check_locked(radio_t* const radio, radio_register_t reg)
+{
+	return radio->regs_locked & (1 << reg);
+}
+
 radio_error_t radio_reg_write(
 	radio_t* const radio,
 	const radio_register_bank_t bank,
@@ -76,6 +82,10 @@ radio_error_t radio_reg_write(
 		return RADIO_ERR_INVALID_REGISTER;
 	}
 
+	if (check_locked(radio, reg)) {
+		return RADIO_ERR_LOCKED_REGISTER;
+	}
+
 	switch (bank) {
 	case RADIO_BANK_ACTIVE:
 		mark_dirty(radio, reg);
@@ -106,6 +116,20 @@ uint64_t radio_reg_read(
 	return radio->config[bank][reg];
 }
 
+radio_error_t radio_reg_lock(
+	radio_t* const radio,
+	const radio_register_t reg,
+	const bool locked)
+{
+	if (reg > RADIO_NUM_REGS) {
+		return RADIO_ERR_INVALID_REGISTER;
+	}
+
+	radio->regs_locked = (radio->regs_locked & ~(1 << reg)) | (locked << reg);
+
+	return RADIO_OK;
+}
+
 static uint32_t radio_update_direction(radio_t* const radio, uint64_t* bank)
 {
 	const uint64_t requested = bank[RADIO_OPMODE];
@@ -928,3 +952,68 @@ void radio_switch_opmode(radio_t* const radio, const transceiver_mode_t mode)
 	nvic_enable_irq(NVIC_USB0_IRQ);
 	radio_update(radio);
 }
+
+bool radio_set_config_mode(radio_t* const radio, const radio_config_mode_t mode)
+{
+	// Check if the requested mode is supported.
+	switch (mode) {
+	case RADIO_CONFIG_STANDARD:
+		// supported on all boards
+		break;
+#ifdef IS_PRALINE
+	case RADIO_CONFIG_HALF_PRECISION:
+	case RADIO_CONFIG_EXT_PRECISION_RX:
+	case RADIO_CONFIG_EXT_PRECISION_TX:
+		// only supported on praline
+		if (!IS_PRALINE) {
+			return false;
+		}
+		break;
+#endif
+	default:
+		return false;
+	}
+
+	// Don't do anything if we're already in the requested mode.
+	if (mode == radio->config_mode) {
+		return true;
+	}
+
+#if defined(IS_PRALINE) && !(defined(DFU_MODE) || defined(RAM_MODE))
+	if (IS_PRALINE) {
+		fpga_bitstream_index_t bitstream_index;
+		switch (mode) {
+		case RADIO_CONFIG_STANDARD:
+			bitstream_index = FPGA_BITSTREAM_STANDARD;
+			break;
+		case RADIO_CONFIG_HALF_PRECISION:
+			bitstream_index = FPGA_BITSTREAM_HALFPREC;
+			break;
+		case RADIO_CONFIG_EXT_PRECISION_RX:
+			bitstream_index = FPGA_BITSTREAM_EXTPREC_RX;
+			break;
+		case RADIO_CONFIG_EXT_PRECISION_TX:
+			bitstream_index = FPGA_BITSTREAM_EXTPREC_TX;
+			break;
+		default:
+			return false;
+		}
+
+		// Reset radio state.
+		for (uint8_t reg = 0; reg < RADIO_NUM_REGS; reg++) {
+			radio_reg_write(radio, RADIO_BANK_ALL, reg, RADIO_UNSET);
+		}
+
+		// Load bitstream.
+		extern struct fpga_loader_t fpga_loader;
+		if (!fpga_image_load(&fpga_loader, bitstream_index)) {
+			return false;
+		}
+	}
+#endif
+
+	// Update radio config mode.
+	radio->config_mode = mode;
+
+	return true;
+}

firmware/common/radio.h

@@ -34,18 +34,20 @@ typedef enum {
 	RADIO_ERR_INVALID_PARAM = -2,
 	RADIO_ERR_INVALID_BANK = -3,
 	RADIO_ERR_INVALID_REGISTER = -4,
+	RADIO_ERR_LOCKED_REGISTER = -5,
 	RADIO_ERR_UNSUPPORTED_OPERATION = -10,
 	RADIO_ERR_UNIMPLEMENTED = -19,
 	RADIO_ERR_OTHER = -9999,
 } radio_error_t;
 
 /* radio configuration modes */
 typedef enum {
-	RADIO_CONFIG_LEGACY = 0,
-	RADIO_CONFIG_STANDARD = 1,
-	RADIO_CONFIG_EXT_PRECISION_RX = 2,
-	RADIO_CONFIG_EXT_PRECISION_TX = 3,
-	RADIO_CONFIG_HALF_PRECISION = 4,
+	RADIO_CONFIG_STANDARD = 0,
+#ifdef IS_PRALINE
+	RADIO_CONFIG_EXT_PRECISION_RX = 1,
+	RADIO_CONFIG_EXT_PRECISION_TX = 2,
+	RADIO_CONFIG_HALF_PRECISION = 3,
+#endif
 } radio_config_mode_t;
 
 typedef struct {
@@ -225,6 +227,7 @@ typedef struct {
 	radio_config_mode_t config_mode;
 	uint64_t config[RADIO_NUM_BANKS][RADIO_NUM_REGS];
 	volatile uint32_t regs_dirty;
+	uint32_t regs_locked;
 	update_fn update_cb;
 } radio_t;
 
@@ -248,6 +251,15 @@ uint64_t radio_reg_read(
 	const radio_register_bank_t bank,
 	const radio_register_t reg);
 
+/**
+ * Lock a register. Prevents any future calls to `radio_reg_write`
+ * from overwriting the current stored value of the register.
+ */
+radio_error_t radio_reg_lock(
+	radio_t* const radio,
+	const radio_register_t reg,
+	const bool locked);
+
 /**
  * Apply changes requested in RADIO_BANK_ACTIVE.
  * Return true if any changes were applied.
@@ -260,6 +272,12 @@ bool radio_update(radio_t* const radio);
  */
 void radio_switch_opmode(radio_t* const radio, const transceiver_mode_t mode);
 
+/**
+ * Switch to a new configuration mode.
+ * Return true if the mode was successfully switched.
+ */
+bool radio_set_config_mode(radio_t* const radio, const radio_config_mode_t mode);
+
 /**
  * Driver instance.
  */

firmware/hackrf_usb/CMakeLists.txt

@@ -60,6 +60,7 @@ set(SRC_M4
 	usb_api_spiflash.c
 	usb_api_transceiver.c
 	usb_api_operacake.c
+	usb_api_radio.c
 	usb_api_sweep.c
 	usb_api_selftest.c
 	usb_api_ui.c

firmware/hackrf_usb/hackrf_usb.c

@@ -75,6 +75,7 @@
 #include "usb_api_board_info.h"
 #include "usb_api_m0_state.h"
 #include "usb_api_operacake.h"
+#include "usb_api_radio.h"
 #include "usb_api_register.h"
 #include "usb_api_selftest.h"
 #include "usb_api_spiflash.h"
@@ -182,6 +183,13 @@ static usb_request_handler_fn vendor_request_handler[] = {
 	usb_vendor_request_write_radio_reg,
 	usb_vendor_request_read_radio_reg,
 	usb_vendor_request_get_buffer_size,
+	usb_vendor_request_lock_radio_reg,
+	usb_vendor_request_open,
+	usb_vendor_request_close,
+	usb_vendor_request_set_radio_mode,
+	usb_vendor_request_set_radio_frequency,
+	usb_vendor_request_set_radio_frequency_explicit,
+	usb_vendor_request_set_radio_sample_rate,
 };
 
 static const uint32_t vendor_request_handler_count =

firmware/hackrf_usb/usb_api_radio.c

@@ -0,0 +1,141 @@
+/*
+ * Copyright 2026 Great Scott Gadgets <info@greatscottgadgets.com>
+ *
+ * This file is part of HackRF.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; see the file COPYING.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street,
+ * Boston, MA 02110-1301, USA.
+ */
+
+#include <stddef.h>
+#include <stdint.h>
+
+#include <fixed_point.h>
+#include <radio.h>
+#include <usb_request.h>
+#include <usb_type.h>
+
+#include "usb_queue.h"
+
+usb_request_status_t usb_vendor_request_set_radio_mode(
+	usb_endpoint_t* const endpoint,
+	const usb_transfer_stage_t stage)
+{
+	if (stage == USB_TRANSFER_STAGE_SETUP) {
+		radio_config_mode_t mode = endpoint->setup.value;
+		if (!radio_set_config_mode(&radio, mode)) {
+			return USB_REQUEST_STATUS_STALL;
+		}
+		usb_transfer_schedule_ack(endpoint->in);
+	}
+
+	return USB_REQUEST_STATUS_OK;
+}
+
+usb_request_status_t usb_vendor_request_set_radio_frequency(
+	usb_endpoint_t* const endpoint,
+	const usb_transfer_stage_t stage)
+{
+	static fp_40_24_t hz_param;
+
+	if (stage == USB_TRANSFER_STAGE_SETUP) {
+		usb_transfer_schedule_block(
+			endpoint->out,
+			&hz_param,
+			sizeof(fp_40_24_t),
+			NULL,
+			NULL);
+	} else if (stage == USB_TRANSFER_STAGE_DATA) {
+		radio_reg_write(&radio, RADIO_BANK_ACTIVE, RADIO_FREQUENCY_RF, hz_param);
+		radio_reg_write(
+			&radio,
+			RADIO_BANK_ACTIVE,
+			RADIO_FREQUENCY_IF,
+			RADIO_UNSET);
+		radio_reg_write(
+			&radio,
+			RADIO_BANK_ACTIVE,
+			RADIO_FREQUENCY_LO,
+			RADIO_UNSET);
+		radio_reg_write(
+			&radio,
+			RADIO_BANK_ACTIVE,
+			RADIO_IMAGE_REJECT,
+			RADIO_UNSET);
+		usb_transfer_schedule_ack(endpoint->in);
+	}
+
+	return USB_REQUEST_STATUS_OK;
+}
+
+usb_request_status_t usb_vendor_request_set_radio_frequency_explicit(
+	usb_endpoint_t* const endpoint,
+	const usb_transfer_stage_t stage)
+{
+	static struct {
+		fp_40_24_t if_freq_hz;
+		fp_40_24_t lo_freq_hz;
+		uint8_t path;
+	} params;
+
+	if (stage == USB_TRANSFER_STAGE_SETUP) {
+		usb_transfer_schedule_block(
+			endpoint->out,
+			&params,
+			sizeof(params),
+			NULL,
+			NULL);
+	} else if (stage == USB_TRANSFER_STAGE_DATA) {
+		radio_reg_write(
+			&radio,
+			RADIO_BANK_ACTIVE,
+			RADIO_FREQUENCY_IF,
+			params.if_freq_hz);
+		radio_reg_write(
+			&radio,
+			RADIO_BANK_ACTIVE,
+			RADIO_FREQUENCY_LO,
+			params.lo_freq_hz);
+		radio_reg_write(
+			&radio,
+			RADIO_BANK_ACTIVE,
+			RADIO_IMAGE_REJECT,
+			params.path);
+		usb_transfer_schedule_ack(endpoint->in);
+	}
+
+	return USB_REQUEST_STATUS_OK;
+}
+
+usb_request_status_t usb_vendor_request_set_radio_sample_rate(
+	usb_endpoint_t* const endpoint,
+	const usb_transfer_stage_t stage)
+{
+	static fp_28_36_t sps_param;
+
+	if (stage == USB_TRANSFER_STAGE_SETUP) {
+		usb_transfer_schedule_block(
+			endpoint->out,
+			&sps_param,
+			sizeof(fp_28_36_t),
+			NULL,
+			NULL);
+	} else if (stage == USB_TRANSFER_STAGE_DATA) {
+		radio_reg_write(&radio, RADIO_BANK_ACTIVE, RADIO_SAMPLE_RATE, sps_param);
+		usb_transfer_schedule_ack(endpoint->in);
+	}
+
+	return USB_REQUEST_STATUS_OK;
+}