RadAsm30 Files

WiFi Scope
----------

Specifications:
-----------------------------------------------------------
o Digital Osilloscope
  o Input
    - 1 MOhm
    - AC / DC
    - 50mV to 2V / Div
    - 8MHz at -3db, without probe and 3.3Vpp sqear wave
    - Max 16MHz, without probe and 3.3Vpp sqear wave
  o Timebase
    - 50ns to 1s / Div
    - Sliding wave mode on 250ms,500ms and 1s / div.
    - Normal mode on 5us to 100ms / div.
    - Single shot mode on 5us to 1s / div
    - Fast mode on 50ns to 2.5us / div.
      Minimum input frequency 100KHz.
      40MHz worst case sample rate.
      200MHz best case sample rate.
      When using the HS Clock as signal source, worst
      case is always true. Single shot not possible.
  o Trigger
    - Pre trigger
    - Rising edge
    - Falling edge
    - None
    - Sensivity ~100mV
  o Position
    - Horisontal
    - Vertical +/- 8.0V
    - Trigger +/- 8.0V
  o Single shot
    - 4K sample buffer.
  o Hold
    - Freezes the wave
  o Auto
    - Configures scope to best fit the
      input signal.
  o Frequency, period and curve quality.

o Digital voltmeter DC and AC RMS
  o X1 probe:
    - 1 MOhm
    - +/-8V DC
    - 5.5V AC RMS
  o X10 probe:
    - 10 MOhm
    - +/-80V DC
    - 55V AC RMS

o Waveform generator
  - Off, Sine, Triangle, Squear, Sawtooth, Reverse Sawtooth and DC out
  - 500Hz to 10KHz in 1, 2, 5 steps
  - First and second harmonics amplitude settings
  - 0V to 3Vpp output
  NOTE:
  The blocking of the 1MHz PWM signal is not perfect.
  If this is a problem, connect a 4n7 capacitor at the probe
  output. This will improve blocking but decrase amplitude.

o High speed squear wave generator
  - 3.3Vpp output
  - 1Hz to 20MHz frequency
  - Resolution: Any frequency that can be
    obtained by dividing 80MHz clock
  - Dutycycle: 0% to 100% in 1% steps

o DDS squear wave generator with sweep
  - 3.3Vpp output
  - 1Hz to 2MHz
  - Resolution: 1Hz
  - Sweep: 1% to 100% in 1, 2, 5 steps
  - Sweep time: 1s to 100s  in 1, 2, 5 steps
  - Sample rate 8MHz
  NOTE:
  Done in software. Stops when you leave the function.
  At high frequency there might be significant jitter.

Parts list:
-----------

Miscellanous:
-------------
1 x Double sided 10cm by 7cm pcb
1 x STM32F103C8T6 (blue pill) and ST-Link programmer dongle
1 x ESP8266 WiFi module
2 x 20 pin single row female connector
1 x 2 x 4 pin dual row female connector
2 x 3 pin angled male connector (See *)
1 x SIP-1A05 5V reed relay
1 x TSV772IDT SO8 Dual OP Amp IC
1 x TL712 DIL8 Comparator IC

* Connector:
------------
If you will use a scope probe, replace scope input with a BNC connector

Capacitors:
-----------
2 x 470uF Electrolytic
5 x 47uF Tantal
1 x 1uF Metal film
2 x 100nF Metal film or Ceramic
1 x 4n7 Ceramic
1 x 33p Ceramic
1 x 10p Ceramic
1 x DIY Trimmer ~10pF+10pF (2 x 5cm ~0.5mm enamelled copper wire. (See *)

* DIY Trimmer capacitor:
------------------------
Made from a twisted pair ~0.5mm enamelled copper wire, length ~5cm.
Twist 1cm and leave the rest untwisted for final adjustment.
Add the 10pF ceramic capacitor in parallell.
See the WiFi_Scope.cad.

Resistors (metal film 1%):
--------------------------
1 x 470K
1 X 330K
3 x 100K
1 x 5K6
1 x 4K7
1 x 3K3
2 x 1K
1 x 470 Ohm
2 x 330 Ohm
1 x 220 Ohm
2 x 100 Ohm

Creating the PCB:
-----------------

I am using:
  HP Laserjet Professional P1102 printer.
  A4 toner transfer paper.
  Cooking ware with a flat, thick bottom and
  heating it to around 150C on the stowe.

Printout:
  If you are using different printer / paper size
  then adjust the size of the outer thin frame
  on both the top and bottom PCB designs. You
  must have exactly 2.54mm (0.1 inch) pitch. 
  The printout is landscape.

Preparations:
  Cut the PCB to 10cm x 7cm.
  I am doing the top PCB side first.
  Clean the PCB, avoid touching the copper after cleaning.
  Make a hole with a pin in the paper printout,
  upper left and bottom right corners.
  Wrap the printout around the PCB and secure it with masking tape.
  Drill hples where you made the holes in the paper.
  You need these holes when you align the PCB top and bottom.

Toner transfer:
  Place the PCB on a pice of cloth, paper side up.
  Heat up the cooking ware. Place it on the PCB and apply as much
  presure as you can. Wriggle it around and pay extra attention
  to the PCB edges.

Removig the toner transfer paper:
  Soak the PCB in warm water for a few minutes.
  Remove the paper by rubbing the PCB with your thumb.
  If the transfer was successful you dont need to be
  careful. Inspect and make shure you got rid of all the paper.
  Minor errors can be fixed with a permanent ink pen.

Etching:
  Cover the bottom side with packing tape and etch the PCB.

Repeat the process with the bottom PCB side. Make shure you
allign and orientate the top and bottom correctly.

Drilling the hples:
  I am using a home made hand held drill with a motor from
  an old worn out electric toothbrush. The drill bit is 0.6mm.
  Use a 0.8mm drill bit for the connectors and reed relay.

Soldering:
  Use a fine tiped soldering iron and thin (<=1mm) soldering tin.
  A combination of surface mount and through hole is used.
  Some componens should be soldered on both sides, others on the
  bottom or top only.
  The TSV772IDT might not have a pin 1 marking. See TSV772IDT drawing for
  correct orientation.
  I soldered in this order:
  1. TSV772IDT
     The SO8 package is tiny. The best way to solder it is probably by
     adding some tin to pin 8 on the pcb and then hold the ic in place
     while soldering pin 8.
  2. TL712, bend the legs
  3. Feed througs and wire jumpers
  4. Resistors
  5. DIY trimmer
  6. Capacitors
  7. Connectors
  8. Reed relay
  Between each step, check for solder bridges and bad connections.
  Check by taking pictures with your phones camera.
  If in doubt, check with a multimeter.

Installing the project:
-----------------------
Unzip WiFiScope.zip to an empty folder.
Move the content to C:\RadSTM32\STM32_F103\Projects
Start RadSTM32 and open the project.

Programming the STM32F103C8T6:
------------------------------
Before inserting the STM32F103C8T6 it must be programmed.
Connect the ST-Link programmer dongle to the STM32F103C8T6
and then to your PC. In RadSTM32 open the WiFiScope project.
Now is the time to choose if you will be using the ESP8266 or
your WiFi router as the access point (See main.h).
If you make any changes, rebuild the project by pushing
[Assemble] button or by selecting Make / Assemble from the menu.
Upload the code by pushing [Run] button or by selecting
Make / Run from the menu. After ~20 seconds the led should
start blinking slowly, indicating that the ESP8266 is missing.

Testing:
--------
Insert the ESP8266 and STM32F103C8T6 boards and connect the
usb cable to a 5V power source (PC, charger or power bank).
The led should be on. If not disconnect and check your soldering.
On your phone, verify that you can select the ESP8266 as the
access point.
Open your phons internet browser and enter the url: http://192.168.4.1
After a sew secons the scope screen shoul show and the led should
blink fast, indicating communication.

Your WiFi router as the access point:
-------------------------------------
If you selected your WiFi router as access point you can find the
assigned IP by connecting to the ESP8266 and use
the url: http://192.168.4.1/ip

Scope overshot / undershot adjustment:
--------------------------------------
Connect a jumper wire from HS Clock pin 3 to scope pin 3.
Select the HSC tab.
Set the the HS Clock to 10KHz and 50% duty cycle.
Select the Scope tab and set sensivity to 500mV / div and timebase
to 10us / div. Select rising edge trigger.
Twist / untwist DIY  trimmer until you get a nice squear wave.
Cut off excess wires. Leave a few mm for fine tuning.

KetilO