How to build a RBBX BLHeli-Setup-Box.

Transcription

1 How to build a RBBX BLHeli-Setup-Box. I. Introduction: The RBBX Box is a dual interface solution for BLHeli. Together it 1. Together with a USB/RS232 serial connection and with the Windows Application "BLHeli-Setup" it can be used as a "Toolstick" substitute. One can flash any appropriate target BESC with the BLHeli firmware and configure all available Settings as usual. The flashing of the whole firmware is a bit slower than with the Silabs Toolstick, but tales only about 3-4 seconds to finish (Silabs Toolstick seconds). In addition, "BLHeli-Setup" has also a function to update the firmware of the RBBX-Box. So the standalone part of the Box can be adapted to new BLHeli revisions. The protocol of the interface is or will be well enough documented, so anyone can build an own software solution. 2. Together with an 1 or 2s Lipo it can be used as a standalone mobile programming Box for any BLHeli flashed BESC. II. What You need: 1. One Robby Programmer V2 No One USB/Serial converter with 5V output (FTDI chips work fine, others not tested so far). 3. Two 3 pin servo cables; one for the connection Serial-converter to the box and one for the Lipo connection (standalone function). The best is to use ones with the Robbe standard, because it has a reverse polarity insurance. But according to my tests, a reverse connection, does not damage the box. 4. The "BLHeli-Setup" application with the additional or included Interface support package. In addition, only one time, You need an arbitrary AVR-ISP programming interface to prepare the ATMEGA88PA AVR MCU of the box (erase the chip, set the fuses/lockbits and write a bootloader firmware part into the box).

2 III. Prepare the USB/serial converter: 1. Make a connection between the TX and RX pins of the converter output. 2. Solder the servo cable to the converter. GND -> Minus pole (usually black or brown) VCC 5V+ -> Plus pole (usually red) TX/RX -> Signal pole (usually orange or white) 3. Configure the converter for 5V (often done by a solder bridge or jumper). The TX and RX output can be configured with the FTDI software from but should usually left in normal state (not inverted). Here is an example image provided. The shown connections need to be modified for the corresponding hardware.

3 IV. Prepare the RBBX Box Bootloader Flash: Disassemble the box. The modifications refer to the following picture: 1. If You ever want to supply the Box with less than 4.5V (e.g. with 1s lipo) You should bridge D1 for higher LCD contrast as shown. Otherwise You will not be able to read the display. 2. Solder the ISP connections to the appropriate pads: SCK, VCC, MISO, MOSI, GND, RESET. 3. Connect the AVR-ISP programmer and the USB/serial converter with Servo cable to provide the necessary 5V.

4 V. Flashing the Bootloader Start the programmer tool (here I use AVRStudio 5.1). Set ATMEGA88PA as device and apply. 1. Erase the Chip with "Erase now" 2. Select the appropriate Bootlader file ("RBBXm88P8b01.hex" from directory "...\BLHeli- Setup\RBBX\Bootloader) and "Program". Now You need to set the Fuses to support the bootloader: Set the size (BOOTSZ) for the bootloader to 256 words (512 bytes!). 1. Enable the reset vector for the bootloader (BOOTRST) and "Program".

5 Now, optional, You can set the lock bits to protect the bootloader against accidental overwrite: 1. Set BLB1 to "LPM_SPM_DISABLE" and "Program". VI. First Flash of the firmware Now You should disconnect the AVR ISP programmer and start BLHeli-Setup to flash the firmware. First enable "Options\Serial Interface"... and change to the page "Serial Interfaces / Boxes"...Select the right COM port...and click "Flash RBBX Box" baud should work fine. Now pick the appropriate hex file from "...\BLHeli-Setup\RBBX" (BLHeli-Setup will look for files starting with "RBBX" only) The appropriate Eeprom file will be picked accordingly. So: there allways have to be 2 files which are named like: RBBX...vXX.hex (Flash) and RBBX...vXX.eep (Eeprom). After a short time... The connection to the bootloader should be established and You are asked to confirm...

6 VII. Check interface connection Now You may check the connection for the first time with BLHeli-Setup and should get this warning message: Now, You may remove the AVR ISP programmer connection and do the last part of the work: VIII. Finally... Solder the 3-pin wire to the board of the box as shown: For some, this may be the most difficult part, but magnifier glasses may help a lot! Finally, for the cable to BESC, You must cut a small cutout in the housing and assemble the box. Thanks a lot to Hagen Re for sharing his AVRootloader (AVR Bootloader) project. This bootloader is small enough (<512 bytes) and though provides Eeprom writing access. For further info see: