Restoring bricked Eachine ProDVR after firmware update

If your ProDVR is bricked after firmware update process, you can easily restore it by flashing firmware directly to the serial flash ship.

What you will need:

• Arduino Mini Pro atmega328 board. (16Mhz 5V, about 1.30$)

It is also possible to use Arduino Nano with atmega328 (16Mhz)

(Possible variants on ebay: https://goo.gl/zd0twR, Banggood: https://goo.gl/MDmy3E)

• USB to Serial adapter. It can be FTDI, CH340G  (just look for ones that support 3.3V , about 1.30$)

(Possible variants on ebay: https://goo.gl/Ru7BXF)

• Thin wires for connecting Arduino and Serial Flash

Next parts are needed if Arduino outputs more than 3.3V on signal pins:

• Resistors for level divider 5k and 10k both (2 pcs of each value)
• Breadboard (not necessary, but very convenient)

Software

• Flashrom programming utility (https://www.flashrom.org ). If your PC runs on Windows then I recommend to download already compiled windows version here: http://ra.openbios.org/~idwer/flashrom/mingw/
• XLoader to upload binary file to Arduino board (http://russemotto.com/xloader/ )
• Arduino firmware (frser-duino.hex) (download link: https://goo.gl/11m5pP)
• ProDVR firmware file (flash.hex) (download link: https://goo.gl/YdZLlO)

Steps

Flashing Serprog firmware to Arduino Mini Pro:

1.    Connect USB – TTL converter to Arduino Mini Pro board

2.    If everything is ok, You should see “FTDI” or “USB-SERIAL CH340” device in device manager

3.    Connect Arduino Mini Pro to USB-TTL adapter (check that your FTDI or USB Serial adapter uses 3v for powering)

4.    Start Xloader, open [fser-duino.hex] file, set the right com port and hit “Upload”.

Now You have Flashrom compatible programmer.

5.    Connect ProDVR flash IC to the Arduino. Use supplied connection schematics. For this you need to lift a bit VCC pin of the serial flash to disconnect from the rest of the board electronics and solder 5 wires: VCC, GND, CS, CLK MOSI and MISO. Try to keep them as short as possible, about 10cm. Use small diameter wire.

Connection table:

FLASH CHIP - ARDUINO

VCC (pin 8 ) to Arduino  3.3V output (5V would likely kill the chip, be carefull)

GND (pin 4) to Arduino GND pin

CS (pin 1) to Arduino pin 10

DO (pin 2) to Arduino pin 12

DI (pin 5) to Arduino pin 11

Clock (pin 6) to Arduino pin 13

Schematics (only if Arduino outputs 3.3V signal levels):

6.    Once connected, try reading the contents of flash IC by running this command:

mingw32-w64-flashrom-r1781.exe --programmer serprog:dev=COM10:115200 -c MX25L1605 

--read test.hex

You should get similar output to this:

E:\My\RC\Flashrom>mingw32-w64-flashrom-r1781.exe --programmer serprog:dev=COM10:115200 

-c MX25L1605 --read test.hex

flashrom v0.9.7-r1781 on Windows 6.2 (x86)

flashrom is free software, get the source code at http://www.flashrom.org

Calibrating delay loop... OK.

serprog: Programmer name is "frser-duino"

Found Macronix flash chip "MX25L1605" (2048 kB, SPI) on serprog.

Reading flash... done.

7.    If everything goes OK by this far, you are ready to flash the firmware. To flash the device, start this command:

mingw32-w64-flashrom-r1781.exe --programmer serprog:dev=COM16:115200 -c MX25L1605 

--write flash.hex

You should get similar output to this:

E:\My\RC\Flashrom>mingw32-w64-flashrom-r1781.exe --programmer serprog:dev=COM16:115200 

-c MX25L1605 --write flash.hex

flashrom v0.9.7-r1781 on Windows 6.2 (x86)

flashrom is free software, get the source code at http://www.flashrom.org

Calibrating delay loop... OK.

serprog: Programmer name is "frser-duino"

Found Macronix flash chip "MX25L1605" (2048 kB, SPI) on serprog.

Reading old flash chip contents... done.

Erasing and writing flash chip... 

Erase/write done.

Verifying flash... VERIFIED.

You are done! Now reconnect serial flash chip Power pin to the PCB and try to power your ProDVR. You should see something similar to this:

Insert SD card and you good to go!

If you have questions or you need more details, then write a comment.

                      

Eachine ET526 VTX transmitter review

Link to product page:  Eachine ET526 VTX Transmitter

This VTX has 4 power levels: 0 mW – 25 mW – 200mW – 600mW, 5 bands: A – B– C – D – E, 40 channels total. 
Weight is 8.5 grams. This is slightly more than typical VTX weights and this is mainly because of the heat sink attached.

Heatsink plate on the top

LEDS for Band, Channel, Power level ant TX ON indicator

Size is almost the same as other similar VTX‘es

First interesting feature is Transmitting Power OFF on startup. Every time you power this VTX, it starts with TX power OFF (TX led is dim). You have to double click upper button after you power up the VTX to turn video transmission on.
Second interesting feature is on-board microphone, which can be turned ON and OFF 
Changing of the channels and bands is done with lower button pressing. Short press of the button to change channel, longer press (2sec) for changing band and long press (5sec) for on-board microphone On/Off.
Double click of the upper button turns the video transmitting on. Longer press (3sec) changes power level selection 25 – 200 – 600 mW.
Cable is 6-pin JST-SH 1.25mm one. Cable has a 3-pin camera connector on another end of the cable, also female servo connector for Power in (7-24V) and female servo connector for PWM input. Camera connector compatible with Eachine 1000TVL CCD camera.
Antenna connector is SMA type. This is good for VAS/Fatshark users as their antennas have SMA connectors. Others can use SMA->RP-SMA type changing adapter (like this one: https://goo.gl/Cfbc9p).

I have measured the output voltage for camera under load (Eachine CCD 100TVL). It turned to be 5.16V while transmitter is TX OFF and 5.19V when TX in ON. The same for all power levels. 

Current measurements
Power level: 0 mW, Power usage: 20mA
Power level: 25 mW, Power usage: 120mA
Power level: 200 mW, Power usage: 210mA
Power level: 600 mW, Power usage: 310mA


Pros
• Switchable transmitting power level – from ZERO to 25, 200, 600 mW. 
• 5 bands, total of 40 Channels
• Video transmitter can be turned OFF/ON. 
• Has on-board microphone
• On board microphone can be turned OFF;
• Remembers last settings after power off-on cycle (except transmitting is turned off every time VTX is power cycled)
• Has 5V output for camera
• Channels can be switched by PWM signal from receiver

Cons
• You need to manually turn on the transmitter every time you plug the battery. Have this is mind when installing this VTX into your quad/aircraft
• Tends to reset (rarely) to default channel/band after multiple battery connects/disconnects


Additional thoughts
• This transmitting OFF by default feature is good, but not always wanted one. In the future revisions I suggest to make a setting – weather to start the VTX with TX power OFF or to start with TX ON by default. Could be made in such a way: Press upper button for 5 seconds to switch between these two modes
• Bands are somehow mixed up. You have to search for the right band on your RX, because letters doesn’t correspond to usual band labeling.

Eachine ET526 VTX FPV transmitter review (9 min 14 sec)

Eachine TX526 FPV video transmitter review

I have bench tested Eachine TX526 video transmitter, which I received from Banggood. 

This VTX has 4 power levels: 0 mW – 25 mW – 200mW – 600mW, 5 bands: A – b – E – F – r, 40 Channels total. 
Weight is 7.1grams, exactly the same as TX5828. Size is almost the same as other similar VTX‘es:

Size comparison with other transmitters

Changing of the settings can be easily done with just one button. Short press of the button to change channel, longer press (2sec) for changing band and long press (5sec) for power level selection.

It has RP-SMA antenna plug, despite some misleading information on the user manual leaflet. 

Cable is 5-pin JST-SH 1.0mm one. The same cable and pinout fits TX5828 transmitter. 

Current Draw measurements
Power level: 0 mW, Power usage: 40mA

Power level: 25 mW, Power usage: 110mA

Power level: 200 mW, Power usage: 220mA

Power level: 600 mW, Power usage: 300mA




Pros
• Easy to setup – one button. 
• Has 4 power levels 
• Can be set at 0 mW power level (TX off)
• Remembers last settings after power off-on cycle
• 5pin JST-SH (1.0mm) cable, widely used in other transmitters

Cons
• None

Additional thoughts
• This VTX has interesting feature - turn transmitting power to 0mW. This setting can be usefull if you want to test/tune your quad in line of sight flight or while making some work on the bench. Also can be usefull for powering quad without VTX on racing events.

Eachine TX526 FPV video transmitter review (6 min 1 sec)

In the second part of the review I will test this VTX in the flight, make a test range, measure temperature and more.

This VTX was provided by Banggood for review