Documentation updates for STLinkForm design, including images.

.vscode/settings.json

@@ -14,5 +14,6 @@
         "UART",
         "USART"
     ],
-    "files.autoGuessEncoding": false
+    "files.autoGuessEncoding": false,
+    "files.encoding": "utf8bom"
 }

Hardware/STLinkForm/FABRICATION.md

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+# Fabrication Hints (V2)
+
+## JLCPCB Order
+
+For the fabrication of samples, use the [output\STLinkForm-grumat.zip](output\STLinkForm-grumat.zip) 
+file. This can be sent directly to JLCPCB, as designed was once approved 
+and produced in 08-Dec-2022.
+
+These are the order details:
+
+| Property                | Value                                 |
+|:------------------------|:--------------------------------------|
+| Base Material           | FR-4                                  |
+| Layers                  | 2                                     |
+| Dimension               | 72.5 mm * 59.7 mm                     |
+| PCB Thickness           | 1.6                                   |
+| Impedance Control       | No                                    |
+| PCB Qty                 | 5 (min)                               |
+| PCB Color               | Green (option for fastest production) |
+| Silkscreen              | White                                 |
+| Via Covering            | Tented                                |
+| Surface Finish          | HASL(with lead)                       |
+| Deburring/Edge rounding | No                                    |
+| Outer Copper Weight     | 1                                     |
+| Gold Fingers            | No                                    |
+| Flying Probe Test       | Fully Test                            |
+| Castellated Holes       | No                                    |
+| Remove Order Number     | No                                    |
+| 4-Wire Kelvin Test      | No                                    |
+| Material Type           | FR4-Standard TG 135-140               |
+| Paper between PCBs      | No                                    |
+| Appearance Quality      | IPC Class 2 Standard                  |
+| Confirm Production file | No                                    |
+| Silkscreen Technology   | Ink-jet/Screen Printing Silkscreen    |
+| Cost                    | €3.80 for 5 pcs                       |
+
+> Note that the file **does not contain** information for pick and place 
+> mounting by [JLCPCB](https://jlcpcb.com/). These are just hand soldered. 
+
+
+## Soldering Tips
+
+These are the most important hints:
+
+- A real game changer for mounting SMD components was the acquisition of 
+a magnifying lense, directly coupled to my glasses:  
+[Carson 2x Clip and Flip Power Magnifying Lenses](https://amzn.eu/d/3bhR9gK)
+- Tweezers and a couple of toothpicks will help handle the tiny parts.
+- The recommended mounting order is very important for a good result.
+- Start with components based on it's height. This helps soldering.
+- Through hole elements are always mounted at the last step.
+- Two soldering methods were used;
+  - Solder iron, adding sufficient solder flux to avoid short circuits.
+  - Hot Air gun, using a 1:1 mix of solder paste and flux.
+- Recommended order:
+  - Resistor networks:  **RN1**, **RN2**, **RN3** and **RN4**.  
+  **Method:** Hot air gun.
+  - ICs in the following order: **U2**, **U4**, **U5**, **U8**.  
+  **Method:** Solder iron.
+  - SMD 0603 resistors: all of them.  
+  **Method:** Solder iron.
+  - SMD 0603 fuse (**F1**).  
+  **Method:** Solder iron.
+  - SMD 0603 capacitors: Thickness will vary on these devices and they 
+  are far more trickier than SMD resistors. Solder order will depend on 
+  the specific thickness of each value. Usually lower values have also 
+  lower body sizes, but that is not always true when mixing brands.  
+  **Method:** Solder iron.
+  - SOT packaged ICs: **U1**, **U3**,  **U6**, **U7** and **U9**  
+  **Method:** Solder iron.
+  - Diode and LED: **D1**, **D2**  
+  **Method:** Solder iron.
+  - At this point, perform a shallow clean-up with isopropyl alcohol, a 
+  toothbrush and paper towel.
+  - Any SMD part not listed before should be soldered before continuing 
+  the next step.
+  - SWD jumper **J5** (required only for firmware development).  
+  **Method:** Solder iron.
+  - JTAG 14-pin Connector.  
+  **Method:** Solder iron.
+  - **GDB COMM** 4-pin connector.  
+  **Method:** Solder iron.
+- Following components are completely optional and can be ignored: 
+  - 3 x Jumper set (6-pin, 5-pin and 12-pin) around BluePill.
+  - 3-pin **GND** connector.
+  - 2-pin **3v3** connector.
+  - 2-pin **TVCC** connector.
+
+
+
+## Alternative Components
+
+### Resettable Fuse (F1)
+
+The recommended resettable fuse is for 100 mA. The OpAmp is designed for 
+250 mA, but excessive heat could be produced on that circuit if drawing 
+so much current. A design based on MSP430 is ultra low power and 100 mA 
+is usually much more than typical.
+
+This can be replaced by a low value resistor (2R2 to 4R7), as long as 
+good practice is maintained and no short circuits are made for long 
+periods.
+
+Some valid mouser.com parts are:
+- 0603L010YR
+- PTS060315V010
+
+
+### ESD Protection (U6 and U7)
+
+These chips are dispensable as they have no effect on the device 
+function, except for ESD discharging, which could happen when connecting 
+or reconnecting cables.
+
+In the case these components are not mounted, take care when handling 
+boards, keeping your body discharged (ESD wrist cable or similar 
+procedure).
+
+Besides operating voltage, which is rather standard for these parts, the 
+parasitic capacitance on each pin should be as low as possible.
+
+Some valid mouser.com parts are:
+- XBP15SRV05W-G (1.2 pF)
+- SRV05-4L-TP (1.5 pF)
+- SRV05-4HTG-D (2.4 pF)
+- SRV05-4.TCT (5 pF)
+- CDSOT23-SRV05-4 (5 pF)
+
+
+### JTAG 14-pin Connector
+
+This connector has typically a frame with a centered direction guide. You 
+can use normal 2.54 mm pin-headers instead, but then you need to take 
+care when inserting the JTAG cable that the red line of the flat cable is 
+aligned to the pin 1 mark on the silkscreen (a tiny triangle on the 
+connector drawing).
+
+The best source for this type of component are chinese sites, as 
+mouser.com prices are abysmal.
+
+
+### BluePill/BlackPill Connector
+
+Note that support for the BlackPill is currently *frozen*, so it is 
+perfectly possible to solder single row socket headers instead of the 
+dual row model, since they are more common.
+
+Note at the bottom on the silkscreen the marking for the BluePill variant 
+and solder the socket accordingly.
+
+The best source for this type of component are chinese sites, as 
+mouser.com prices are abysmal.
+
+
+### General Part Number Table
+
+Although most parts are flooded with alternatives, below follows a table 
+with recommended values:
+
+| Designators                   |     Value   | Mouser.com Part Number |
+|:-----------------------------:|:-----------:|:-----------------------|
+| C1, C5, C6, C8                |       10 µF | 81-GRM188Z71A106KA3D   |
+| C2                            |        1 nF | 791-MT18N102J500CT     |
+| C3, C4, C7, C9, C10, C11, C12 |      100 nF | 187-CL10B104KA85PNC    |
+| D1                            |             | 710-151053RS03000      |
+| F1                            |      100 mA | 576-0603L010YR, 504-PTS060315V010 |
+| J1                            |     JTAG    | 710-61201421621        |
+| J4                            |     SWO     | 571-146280-2           |
+| J5                            |     GDB     | 538-171856-1004        |
+| J7                            |   LogicAna  | 571-872247             |
+| R1, R2                        |   47 kΩ | 603-RT0603FRE1347KL    |
+| R3, R4                        |  4.7 kΩ | 603-AC0603FR-7W4K7L    |
+| R5                            |    1 kΩ | 603-RT0603FRE071KL     |
+| RN1, RN2, RN4                 | 4x47 kΩ | 667-EXB-28V473JX       |
+| RN3, RN5                      | 4x100 Ω | 667-EXB-28V101JX       |
+| U1                            |   BluePill  | 855-M20-7832046 (2X)   |
+| U2                            |  AD8531ARTZ | 584-AD8531ARTZ-R, 584-AD8531ARTZ-R7 |
+| U3 | 74xxx2T45DC | 595-SN74LVC2T45DCUE4, 595-SN74LVC2T45DURG4, 595-SN74LVC2T45DCUR, |
+|      |      | 771-AVC2T45DC125, 771-AVCH2T45DC125, 771-74AXP2T45DCH, |
+|  |  | 595-SN74AXCH2T45DCUR, 595-SN74LXC2T45DCUR, 595-SN74AVC2T45DCUR |
+| U4, U5 | 74xxx125 | 771-74LVC125APWQ100J, 771-74LVC125APW-T, 771-ALVC125PW118, |
+|                               |             | 595-N74LVC125AIPWREP   |
+| U6, U7 | SRV05-4 | 865-XBP15SRV05W-G, 833-SRV05-4L-TP, 576-SRV05-4HTG-D, | 
+|                |              | 947-SRV05-4.TCT, 652-CDSOT23-SRV05-4 |
+
+
+> Please check for the last stand on the [output/BlackPill-BMP.csv](output/BlackPill-BMP.csv) 
+> file.
+
+
+## Final Inspection
+
+### PCB Rinsing
+
+Before using the finalized prototype board, perform a thorough clean-up 
+of the PCB removing all paste residue with isopropyl alcohol, toothbrush 
+and paper towel.
+
+### Erasing Flash
+
+Before attaching a BluePill board, make sure that it does not contain a 
+program. This depends on the programmer used.
+
+In my case, and I highly recommend this option, I have a 
+[modified STLink-Clone](https://github.com/grumat/glossy-msp430/wiki/Convert-stlink-to-bmp),
+and using it to erase the flash, through the command line:
+
+```
+cd /d C:\SysGCC\arm-eabi\bin
+C:\SysGCC\arm-eabi\bin>arm-none-eabi-gdb.exe
+GNU gdb (GDB) 10.2.90.20210621-git
+Copyright (C) 2021 Free Software Foundation, Inc.
+License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
+This is free software: you are free to change and redistribute it.
+There is NO WARRANTY, to the extent permitted by law.
+Type "show copying" and "show warranty" for details.
+This GDB was configured as "--host=i686-w64-mingw32 --target=arm-none-eabi".
+Type "show configuration" for configuration details.
+For bug reporting instructions, please see:
+<https://www.gnu.org/software/gdb/bugs/>.
+Find the GDB manual and other documentation resources online at:
+    <http://www.gnu.org/software/gdb/documentation/>.
+
+For help, type "help".
+Type "apropos word" to search for commands related to "word".
+(gdb) tar ext com4
+Remote debugging using com4
+(gdb) mon swdp_scan
+Target voltage: 3.31V
+Available Targets:
+No. Att Driver
+ 1      STM32F1 medium density M3
+(gdb) att 1
+Attaching to Remote target
+warning: No executable has been specified and target does not support
+determining executable automatically.  Try using the "file" command.
+0x080005c8 in ?? ()
+(gdb) flash-erase
+Erasing flash memory region at address 0x08000000, size = 0x20000
+(gdb) detach
+Detaching from program: , Remote target
+[Inferior 1 (Remote target) detached]
+(gdb) quit
+```
+
+> This assume you have installed the ARM compiler for the VisualGDB tool.
+
+### Installing BluePill onto the Prototype Board
+
+Carefully connect the BluePill board, matching the orientation shown on 
+the silkscreen drawing. Check alignment for both pin rows before pushing 
+and sitting it onto the socket.
+
+### Electrical Validation
+
+A minimal checkup is required before using this kit:
+- Ensure that the JTAG connector has no cable connected.
+- Power up the BluePill using an USB cable and connected to your PC.
+- Use a voltmeter and control voltages on the terminals of the prototype 
+board (all voltages must be in a 5% error range):
+  - The black cable of the voltmeter needs to touch the **GND** pad.
+  - Use the red cable to read the list of voltage below:
+  - 3v3 should produce a 3.3V value.
+  - TVCC should also produce a 3.3V value.
+
+If everything is fine, you are ready to go.
+
+If these voltages aren't correct, then your board has some assembly 
+problem, that is causing the issue.  
+Some general hints are:
+  - **Avoid to keep the board connected for a long period until you fix 
+  the issue**.
+  - Check if the red LED of the BluePill daughter-board is on and stable; 
+  you can compare the LED intensity by detaching the daughter-board. The 
+  LED intensity cannot vary too much, since no component of the 
+  proto-board is power-hungry, specially if no cable is present on the 
+  JTAG connector.
+  - Control if the U2 is warming up. In a normal operation no significant 
+  temperature rise should happen. If this is the case verify U2, U3, U4, 
+  U5, U6 and U7 and it's surrounding passive elements, for unwanted shorts.
+  - Check also the temperature of the voltage regulator of the BluePill 
+  (though it sits on the bottom of the board).
+  - A thorough visual inspection is required to locate possible shorts.
+