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About gmpundlik

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    Pune, India
  1. gmpundlik

    Prototype: LogiStart MegaWing

    Sorry about that, I indeed meant using long pins or stackable header on the wing connector. It could be offered as a option or the boards could be shipped without any headers. Long pins seem to be a better idea as a single 16-pin (8x2 ) FRC cable can easily be used on the 12-pin wing header.
  2. gmpundlik

    Prototype: LogiStart MegaWing

    Yes, but those are too big for the space available on the board - PLCC-4 fits inside the body alone of the PLCC6. They are indeed a bit cheaper than the PLCC-4 ones, but the space constraints on the board do not allow them to used. As for the joystick, the most we can do is provide a 6-pin header, but it may be easier to simply use a Arduino style stackable header (e.g. or long pin headers (e.g. ) on the LogicStart MegaWing and connect a external joystick. There is 220/330E series resistor and a 10k pullup connected to these pins (and of course, the slide switches will need to be put on high position), it may be possible to use even a PS/2 joystick in a way similar to that used on the Arcade Megawing, or a simple switch based joystick.
  3. gmpundlik

    Prototype: LogiStart MegaWing

    Well, we have tested the buffered (using a 74LVC3G07 triple open drain buffer) RGB LED driver prototype in India, it works great. The RGB LED (3.5x2.8mm PLCC-4 package) issue is actually has to do with the different pinouts that would pin assignments confusing. Some LEDs use R-CA-G-B and some use B-CA-G-R for the 4 pins. We are figuring out which of the LEDs have better sources. The new board has following modifications: - activate the colon and apostrophe LEDs on the display - add limiting resistors - provide stereo audio instead of mono - add RGB LED To make these changes possible, the micro joystick connections are moved to share pins with the slide switches, so to use the joystick, switches 0 through 4 (5 from the right) need to be at up position. Also, the limiting resistors for the 7seg display are placed on the bottom side, so it will be a bit difficult and expensive to manufacture. The RGB LED may be left out from the final design, but I do hope to have it in the next edition. Would be a good exercise for a LED matrix (especially RGB) controller wing though. Girish
  4. gmpundlik

    loader insists on java runtime

    Hello Jim, It seems the name of the download file was misleading for you. The suffix "-no java-" actually means that the setup is without Java installer, so its about 18~19MB smaller. Those who have Java already installed can just download the main Papilio loader application quickly. It does not mean that its a different version that does not require Java. Nevertheless, the full installer should work, am not sure what happened at your end in this case. Anyway, like Jack said, you do have all the command line tools and scripts to use the application without any GUI. Girish
  5. gmpundlik

    Cannot program Papilio One 250k

    Hi, The command line options are configurable at install time as well as runtime, where you can select one of the following: - Write to SPI flash and quite - Write to FPGA and quit - Start Papilio loader and wait In case of first two options, application will quit only when it can write the bitstream to FPGA or SPI flash successfully. If any error occurs it will not quit and keep the error messages for the user. If one wants to remove the quit step from the first two options above, all you need to do it update the registry setting a tad. Open the following key (see attached image): HKEY_CLASSES_ROOT\Papilio Loader bitstream\Shell\WritePermanently\command or whichever command you wish to modify (from 'EraseFlash', 'Open', 'WritePermanently' or 'WriteToFPGA' ) and remove the switch '-x' from the command line. For example, 'WritePermenantly' option has command line as follows: C:\Program Files\Gadget Factory\Papilio Loader\papilio-loader.exe" "%1" -s -q -x Simple remove "-x" from the above command line so that the loader will not exit whether the operation is successful or not. Please see for detailed description of the application.
  6. gmpundlik

    Papilio loader and multiple FTDI based devices

    I suppose we need to write the board identity (model, version etc) in the EEPROM that we have been shipping blank for so long. Its no longer just the FPGA model, we also have a few variants that use the same setup : FT2232+same FPGA. It will be helpful for our next update for the Papilio Loader app that can identify the boards and resolve between multiple FTDI instances, and employ board and core specific programming methods. Fortunately the FTDI provides utility FT_prog is freely downloadable and saves the EEPROM data in a file, so updating the boards that have already been sold should not be an issue, we can make the EEPROM files available for download.
  7. gmpundlik

    Robotics Wing Features?

    Hi, The RS232 Wing is ready. Hopefully will be in stores soon. Here is a picture of the prototype.
  8. gmpundlik

    Robotics Wing Features?

    Hi EJK, great work! About the RS232 wing - I think DB9 connectors are too bulky to use especially on a mobile robot. I have made a dual RS232 wing (with RTS/CTS handshaking, or can even be used as quad RS232 without handshaking), I already have the PCBs, and waiting for the TSSOP MAX3232s (will arrive by Monday from Digikey). For RS232 connections, I have used two regular 100mil pin headers so as to use inexpensive and easily available cable options. Please see the attached image. For differential recievers, which IC have you used? Its a bit redundant since the FPGA already has differential IOs, maybe a revision of the Papilio board that will route as many differetial pairs as possible, properly will be great, and will solve this problem at no additional cost. Till then, a special wing is probably the way to go. Neverthelss, if speed is not very critical I think even current Papilio boards not routed for differential IO can handle a few tens of Mbits of differential speeds since the pairs are slightly unevenly spaced and mismatched by at the most 100~150mils in most cases which is within recommendations of USB 1.1 standard for 12 Mbps. Maybe we could test that before going for a dedicated wing for the purpose.
  9. gmpundlik

    Robotics Wing Features?

    Its difficult to manage things with just 16 IOs. Currently the IO usage on the board is as follows: Motor control: 24 (4 PWM inputs, sleep control and fault ouput on each of the 4 drivers) - both sleep and fault could be removed, making it 16 IOs for motor control alone ADC SPI interface: 4 Sensor digital inputs: 6 This makes a total of 34 IOs for motor control (8 half-bridges in all which can be used for DC/servo motors, stepper motors or even used in parallel (in the same device) to make one full bridge with current capacity upto 3A) and 6 sensors (both analog and digital) Removing the sleep and fault signals gets us 8 more IOs, making it 22 free IOs onboard. Using 16 of them to a wing slot still leaves 6 odd IOs free which may be used for some onboard features like buzzer, audio output, blinking LEDs, headlights etc. Maybe just a simple power driver with a transistor on 5V brought out on a connector will be ok. It could be used to drive LEDs, a small speaker etc. Also, the ADC has 8 inputs and only 6 are used, the other 2 can be used for dedicated analog sensors or even used to monitor the battery voltage. The supported motor voltage range with DRV8833 is 2.7~10.8V
  10. gmpundlik

    Robotics Wing Features?

    I did mention the sensor interface, but mixed it up with camera, my bad. - which feed into a 74LVC14 schmitt trigger buffer and also a 8-channel SPI ADC, so all the sensors could be used either way. The sensor connectors have a VCC, GND, 1206 footprints for series emitter limiter and parallel load resistors that were intended to be left unpopulated for the user. BTW, the camera interface is meant for the cheap $10 camera used by Voelker, in his SpartCam project. The board has a 300mA 2.8V LDO to supply the camera. The camera interface on the right hand side of the image (supposed to be front for the robot) has the same pinout as that of the camera. The board has 4 sensors interfaces in the front to assist in obstacle detection and two in the rear. The connectors (J2~J7) used are JST 2mm pitch PH type 4-pin vertical connectors. The emitter output (that has the onboard series limiting resistor) can be ignored and it may be used as a 3-wire interface (VCC, GND, Signal) compatible with many analog sensors. Well the camera wing does use 14 IOs. We can indeed simply have those IOs on a open 16-bit (or 2x 8-bit) slot, which can be used by a VGA camera or any other module. The ADC used is the TI ADC088S022 (8 channel, 8-bit, 250ksps but pin compatible with 12-bit, 1Msps part in a family of 9 variants), none of the inputs have any signal conditioning as most analog optical sensors working at the same voltage will not need it when properly tuned, OR the most probably sensor module itself has conditioned outputs. The same sensor signals also goes into the Schmitt trigger buffer, so they may be used as a digital signal as well. The Megawing was designed for a basic robotics projects, to be mounted on a mobile platform. Most advanced projects would need many interfaces, both in terms of numbers and types that would be beyond a simple Megawing with limited IOs and physical space. Yet it also attempts to be as flexible as possible to be usable for a wider range of projects. Provision of open wing slots certainly adds to the flexibility of the board. Girish
  11. gmpundlik

    Robotics Wing Features?

    BTW, as for the requirements for differential lines and relay drivers, I suppose we can leave the camera part (which uses 14 IOs) and in favor of LVDS interface and any other interfaces required (RS232, SPI etc), perhaps another 8-bit SPI based ADC os such. Or simple leave the group of those 14-pins as GPIOs to use with another daughter card.
  12. gmpundlik

    Robotics Wing Features?

    Well, we have been working on a Robotics Megawing - with 2~4 stepper, 2~4 servo, 4~6 sensors (both in analog and digital mode) and a camera interface. The final specs were a bit fuzzy as there are too many options to fit within the 48 IOs and limited physical space available. This is the status of the board I left unfinished (see attached image). It used 4x DRV8833 motor controller (2 H-bridges, capable of 1.5A current, supports low voltage motors 2.7~10.8V typically used in simple robotics projects) which are driven by PWM - could be configured for 4 stepper motors or 8 DC/servo motors or combinations of them. It also has a OV7670 VGA camera interface on the front and 6 sensor interfaces on front and back, which feed into a 74LVC14 schmitt trigger buffer and also a 8-channel SPI ADC, so all the sensors could be used either way. The sensor connectors have a VCC, GND, 1206 footprints for series emitter limiter and parallel load resistors that were intended to be left unpopulated for the user. There was also a version planned for high voltage motors (8~35V) but that might have been classified as a CNC Megawing and been a entirely different product. One of the issues here was possible requirement of a 4-layer board (with thermal pad on the motor driver devices and the continuous copper area it requires, there is not much room for routing the sensor and other connections, especially through two kinds of signal conditioners). Nevertheless, if there is enough interest, we can go ahead and finish this up, with inputs from you guys. Girish
  13. gmpundlik

    Starting Problem with Papilio One

    Hi Anwar, Glad it worked. I guess the cables should also be tested before shipping! Girish
  14. gmpundlik

    Starting Problem with Papilio One

    Well, part availability, manufacturing constraints (most PCB fabs here don't work below 8mils and 0.5mm drills), and catering to mostly student audience (DIY enthusiasts are practically zero here) are some factors that lead to Indian adaptation. Besides,costs of importing the finished boards are already prohibitive with the customs, octroi and local taxes. Jack updates second digit of minor version number while I change just the first digit for committed design, with second digit for short run of an intermediate update. Actually US version 2.04 and Indian 2.55 are practically the same. The Indian version comes with mounting holes and socket headers pre-soldered and USB cable included. V2.70 has a two of the major changes that Jack was probably planning - removing the VCCIO jumper block and adding a poly fuse. Since the board layout was done for simplicity, it does not group the IO banks separately, and there is no point in changing VCCIO for all 48 IOs. It was a bit confusing and would not work anyway for any voltages other than 3.3V. Second is addition of a resettable polyfuse, that can use the space vacated by the jumper block. Third change that would come in handy is routing of port E and F traces. There are 6 matched pairs of traces (if you can see on the lower left part of the board) that support differential pairs on the FPGA. We do not yet have any wing that uses differential signals, but now it is possible to consider one. The Indian version of the PapilioPro will also have some changes, primarily to retain the BOM of the PapilioOne and reduce inventory, assist in local manufacturing and some changes to the BOM to reduce cost. These may reflect in later version of US PapilioPro. Girish