Merge branch 'main' of https://github.com/ArjanteMarvelde/uSDR-pico

README.md

@@ -5,8 +5,8 @@ Furthermore, the repository contains the electronic design of some modules that
 Please see the doc folder for a full description.
 
 The platform used is a Pi Pico module with an RP2040 processor. This processor has dual cores, running at 125MHz each and very configurable I/O, which eases the HW design.
-The software is distributed over the two cores: core-0 takes care of all user I/O and control functions, while core-1 performs all of the signal processing. The core-1 functionality consists of a TX-branch and an RX-branch, each called from a function that waits for inter-core FIFO words popping out. This happens every 16usec, because on core-0 a 16usec timer callback ISR pushes the RX/TX status into that FIFO. Hence the signal processing rythm on core-1 effectively is 62.5kHz.  
-On core-1 the three ADC channels are continuously sampled at maximum speed in round-robin mode. Samples are therefore taken every 6usec for each channel, maximum jitter between I and Q channels is 4usec, which has a negligible effect in the audio domain.  
+The software is distributed over the two cores: *core0* takes care of all user I/O and control functions, while *core1* performs all of the signal processing. The *core1* functionality consists of a TX-branch and an RX-branch, each called from a function that waits for inter-core FIFO words popping out. This happens every 16usec, because on *core0* a 16usec timer callback ISR pushes the RX/TX status into that FIFO. Hence the signal processing rythm on *core1* effectively is 62.5kHz.  
+On *core1* the three ADC channels are continuously sampled at maximum speed in round-robin mode. Samples are therefore taken every 6usec for each channel, maximum jitter between I and Q channels is 4usec, which has a negligible effect in the audio domain.  
 
 The TX-branch 
 - takes latest audio audio sample input from ADC2 (rate = 62.5 kHz), 
@@ -16,18 +16,18 @@ The TX-branch
 - scales, filters and outputs I and Q samples on PWM based DACs, towards QSE output
  
 The RX-branch
-- takes latest I and Q samples from QSD on ADC0 and ADC1 (rate = 62.5 kHz)
+- takes latest Q and I samples from QSD on ADC0 and ADC1 (rate = 62.5 kHz)
 - applies a low-pass filter at Fc=3kHz, 
 - reduces sampling by 4 to get better low frequency response Hilbert xform (rate = 15.625 kHz), 
-- demodulates:
+- demodulates, e.g. SSB:
 -- applies 15-tap DHT on Q channel and 7 sample delay on I channel
 -- subtracts I and Q samples
 - scales, filters and outputs audio on an PWM based DAC, towards audio output
 
-On core0 the main loop takes care of user I/O, all other controls and the monitor port. There is also a LED flashing timer callback functioning as a heartbeat.
+On *core0* the main loop takes care of user I/O, all other controls and the monitor port. There is also a LED flashing timer callback functioning as a heartbeat.
 
-The Pico controls an Si5351A clock module to obtain the switching clock for the QSE and QSD. The module outputs two synchronous square wave clocks on ch 0 and 1, whith selectable phase difference (0, 90, 180 or 270 degrees). The clock on ch2 is free to be used for other goals. The module is controlled over the **i2c1** channel.
-The display is a standard 16x2 LCD, but with an I2C interface. The display is connected through the **i2c0** channel.
+The Pico controls an Si5351A clock module to obtain the switching clock for the QSE and QSD. The module outputs two synchronous square wave clocks on ch 0 and 1, whith selectable phase difference (0, 90, 180 or 270 degrees). The clock on ch2 is free to be used for other goals. The module is controlled over the **i2c0** channel.
+The display is a standard 16x2 LCD, but with an I2C interface. The display is connected through the **i2c1** channel, as well as the bus expanders for controlling the various relays.
 
 ## Open issues: 
 - [x] take care of processing cycles, by moving signal processing parts to the second core
@@ -39,23 +39,23 @@ The display is a standard 16x2 LCD, but with an I2C interface. The display is co
 - [x] SW based VOX
 - [ ] implement RSSI
 - [x] design a set of PCBs
-- [ ] sort out the new HW modules
+- [x] sort out the new HW modules
 - [ ] improve speed: better dual-core management for memory and timer 
-- [ ] add control for new HW: BPF and pre-amp/attenuator switching
+- [x] add control for new HW: BPF and pre-amp/attenuator switching
 
 ## Installing and using the SDK for Windows: 
 Please refer to https://github.com/ndabas/pico-setup-windows/releases where the latest installer can be downloaded (e.g. **pico-setup-windows-0.3-x64.exe**).  
-Execute the installer to set up the SDK environment, e.g. in **~/Documents/Pico**  (let's call this folder $PICO). 
+Execute the installer to set up the SDK environment, e.g. in **~/Documents/Pico**  (let's call this folder **$PICO**). 
 
 ## Building uSDR-pico: 
 Clone/copy the uSDR-pico code files into a subdirectory, e.g. **$PICO/uSDR-pico**  
 Create the build folder: **$PICO/uSDR-pico/build**  
 
-Before doing any building you need to adapt the file **$PICO/uSDR-pico/CMakeLists.txt**, using your favourite browser, to reflect your own directory structure. Also, select whether you want **stdio** to use the UART on pins 1 and 2 or the USB serial port. The monitor terminal is on **stdio**.  
-In **$PICO/** you will find a command to start a Developer Command Prompt window. Within this DCP all environment settings are initialized to enable building.  
-In the DCP window, chdir to the build folder and execute: **cmake -G "NMake Makefiles" ..**  
-Now you have initialized the make environment, and by executing **nmake** in that same build folder, the Pi Pico loadable file **uSDR.uf2** is created.  
-Rebooting the Pico while the bootsel button is pressed will open a file explorer window with the Pico as a Mass Storage Device. Moving the binary to the Pico is as easy as dragging and dropping this uf2 file into that MSD.  
+Before doing any building you need to adapt the file **$PICO/uSDR-pico/CMakeLists.txt**, using your favourite editor, to reflect your own directory structure. Also, select whether you want **stdio** to use the UART on pins 1 and 2 or the USB serial port. The monitor terminal is on **stdio**.  
+In **$PICO/** you will find a command to start a Developer Command Prompt (*DCP*, like a "DOS box"), make sure to use this one instead of any other DOS box. Within this *DCP* all environment settings have been properly pre-set to enable building.  
+In the *DCP* window, chdir to the **build** folder and execute: **cmake -G "NMake Makefiles" ..**   (do not forget the trailing dots).
+Now you have initialized the make environment (for *nmake*) and by executing **nmake** in that same **build** folder, all SDK libraries and finally the Pi Pico loadable file **uSDR.uf2** will be created.  
+Rebooting the Pico while the bootsel button is pressed will open a file explorer window with the Pico shown as a Mass Storage Device (e.g. drive E:). Moving the binary to the Pico is as easy as dragging and dropping this uf2 file into that MSD.  
 
 # Background
 The folder **$PICO/docs** also contains some manuals, of which the *C-SDK description*, the *RP2040 datasheet* and the *Pico Pinout* are absolute must-reads when you start writing software.  
@@ -63,7 +63,7 @@ For calculating filters I have used the free software from Iowa Hills (http://ww
 I also used the online FIR filter calculator T-Filter (http://t-filter.engineerjs.com/) 
 
 # Copyright notice
-The code and electronic designs as well as the implementations presented in this reposiory can be copied and modified freely, for non-commercial use.
-Use for commercial purposes is allowed as well, as long as a reference to this repository is included in the product.
+**The code and electronic designs as well as the implementations presented in this repository can be copied and modified freely, for non-commercial use.
+Use for commercial purposes is allowed as well, as long as a reference to this repository is included in the product.**