R1.00.00 (Patched and renamed to R0.9) - 2017-10-22

Original firmware with the default AGC settings - and a nasty bug preventing normal firmware updates.
The recovery procedure is required to upgrade from this version. Check the instructions in the flashing package.
To prevent further annoyance, this binary was patched and released under a new name: R0.9 for traceability.
This version is supersed by R1.3.

R1.0 - 2018-01-19

This revision of the HF+ firmware enhances the behavior of the AGC and improves the linearity of the Preamp and
the Mixer by setting the Threshold 6 dB lower.

R1.1 - 2018-02-07

This revision improves the linearity of the Preamp by another 6 dB over the previous update with no noticeable
degradation of the noise figure. Note that the gain of the Preamp is compensated in the gain chain, so no level
change should be expected.

R1.2 - 2018-02-15

This revision adds manual settings for the Preamp and the AGC Threshold. The new functionality requires SDR# r1640
or later, but is backward compatible with older software.

R1.3 - 2018-02-16

This revision adds manual ATT setting to control the HF gain distribution and many other fixes. By implementing
the ATT, all the functionality of the previous versions becomes available as user settings. The new functionality
requires SDR# r1642 or later, but it is backward compatible with all older software.

R1.4 - 2018-02-21

The digital gain scaling is set lower to increase the available dynamic range. This step is necessary to convert 18bit
samples out of the DDC to 16bit for streaming. This change does not require an exposed parameter.

R1.5 - 2018-02-22

Fixed a side effect in the STA709 when switching between AGC and manual gain modes. Now the Preamp can only be set when
using the manual gain mode. This version works best with SDR# r1651.

R1.6.1 - 2018-02-24

Optimized the AGC/Manual gain modes. The defaults are now AGC = On, Threshold = High. Also added a low current standby mode when
the device is not streaming.

R1.6.2 - 2018-03-09

This revision moves the digital AGC threshold 15 dB higher and reduces the target margin to -3 dBFS.

R1.6.3 - 2018-03-15

This version adds more IF dynamic range to fit with the 16bit output. The Preamp setting now works without compensation.
The digital margin is -3 dBFS.

R1.6.4 - 2018-03-17

This version optimizes the Preamp gain to match the AGC mode. When disabled, the level is reduced by 25 dB.

R1.6.5 - 2018-03-23

Rewritten the AGC switching code to conform to ST's recommendations.

R1.6.6 - 2018-04-03

Improved the dynamic range and the IF filtering again by another ~8 dB.

R1.6.7 - 2018-04-05

Improved the gain distribution in manual mode.

R1.7.0 - 2018-04-10

Added control code for the HF preselector addon. Improved the gain distribution.

R1.7.1 - 2018-06-09

Fixed a preselector initialization bug.

R1.7.2 - 2018-06-30

Optimized the initialization code.

R1.8.0 - 2018-10-22 (Limited Release)

Added support for more configurable filters in the HF tuner

R2.0.0 - 2019-05-02

Refactored the firmware to run in all chipset revisions

R2.1.0 - 2019-05-31

Added support for STA709CD silicon variant with Fail-Safe boot

R2.2.0 - 2019-06-04

Better underrun/overrun handling. Code cleanup and simplification.

R2.3.0 - 2019-06-26

Improved EMI compatibility.

R2.3.1 - 2019-07-07

Optimized the HF filter corners.

R2.4.0 - 2019-07-08

Optimized the streaming code. Added experimental Low-IF mode at 256 ksps.

R2.5.0 - 2019-07-09

Added soft mute when changing the frequency. More Low-IF enhancements (DC handling, stability).

R2.6.0 - 2019-07-10

Added more sample rates. So far we have 768 ksps Zero-IF, 384 256 and 192 ksps Low-IF.

R2.6.1 - 2019-07-10

Fixed a small Zero IF regression for 768 ksps sample rate.

R2.7.0 - 2019-07-12

Better USB compatibility with old drivers and virtualized hardware.

R2.7.1 - 2019-07-12

More USB buffering for slow hosts. Added dynamic decimation code.

R2.8.0 - 2019-07-13

Many streaming optimizations. Added 912 ksps sample rate.

R2.8.1 - 2019-07-14

Set the default sample rate to 768 ksps for backward compatibility with ExtIO. Buffering optimizations.

R2.8.2 - 2019-07-14

More buffering optimizations for 912 ksps.

R2.8.3 - 2019-07-14

Unlisted 912 ksps until further optimizations. Getting ready for stable release.

R2.9.0 - 2019-07-15

Fixed calibration save/restore issue. Improved the manual gain stability.

R2.9.1 - 2019-07-15

Optimized the corner frequencies of the analog filters for smoother transitions.

R2.9.2 - 2019-07-15

Improved the AGC Reset to ON code.

R2.9.3 - 2019-07-16

Optimized the gain distribution and AGC routines for best dynamic range. The Preamp setting behaves differently.

R2.9.4 - 2019-07-16

More USB streaming optimizations.

R2.9.5 - 2019-07-17

Improved the USB compatibility with Linux and VMs.

R2.9.6 - 2019-07-17

Added support for fragmented streaming (hubs, OTG, etc.)

R2.9.7 - 2019-07-17

Added support for Parallels on Mac. Do they really sell this thing?!

R2.9.8 - 2019-07-18

Added Sleep/Resume mode. Optimized the buffering.

R3.0.0 - 2019-07-19

Added processing gain compensation. Ready for Discovery!

R3.0.1 - 2019-07-30

Adjusted the Minimum AGC threshold to be 4 dB lower.

R3.0.2 - 2019-07-30

Set the AGC on by default.

R3.0.3 - 2019-08-16

Added support code for Pre-selector addon for the HF+ Dual Port.

R3.0.4 - 2019-08-19

Enabled the LNA control for AGC and Manual gain modes.

R3.0.5 - 2019-08-19

Adjusted the Low Gain theshold for the LNA.

R3.0.6 - 2019-08-20

Optimized the high AGC threshold.

R3.0.7 - 2020-06-04

Optimized the USB data streaming. Added 912ksps and 456ksps rates.

R4.0.0 - 2024-03-10

Updated the ST firmware. Better AGC. Faster tuning. More robust USB streaming. Replaced sample rate 256k => 228k.

R4.0.1 - 2024-03-10

Added fall-back support for legacy systems (out-of-date Linux, old libs, etc.)

R4.0.2 - 2024-03-11

Ported the firmware code from Atmel Studio to Visual Studio 2022 + VisualGDB.
Added more compatibility code for manual gain in the HF band.

R4.0.3 - 2024-03-12

Added initialization code to make the unit usable right after flashing, without a hard reset.

R4.0.4 - 2024-03-13

Added 650 ksps sample rate with Low-IF. Stop the streaming when the USB connection is closed.

R4.0.5 - 2024-03-14

Adjusted the buffering to support slow USB controllers and USB hubs.

R4.0.6 - 2024-03-14

Increased the interrupt frequency for better handling of the AGC.

R4.0.7 - 2024-03-14

Fixed the initialization of the 384k and 192k sample rates.

R4.0.8 - 2024-03-14

Faster HF AGC convergence.