Shop OBEX P1 Docs P2 Docs Learn Events
Serial to propeller — Parallax Forums

Serial to propeller

Jonathan HolleJonathan Holle Posts: 48
edited 2010-08-04 19:03 in Propeller 1
Is there somebody who has a pcb of a serial to propeller board ? Mine doesn't work and can't find the mistake ... thanks
«1

Comments

  • Duane DegnDuane Degn Posts: 10,588
    edited 2010-07-28 20:12
    Jonathan,

    By serial, are you referring to a computer serial port (RS-232)?· Do you·want to·transmit and receive or just receive?· If you want to be able to transmit and receive a·MAX3232 type of chip is usually used.

    Here's a link to the data sheet of the chip I·usually use. http://www.intersil.com/data/fn/fn4805.pdf

    I use the standard·circuit on the lower right of page 6.· I generally use·the chip (in a socket) on a Propeller Proto board.· I like using·small·surface mount capacitors·since it saves room on the board and they fit nicely between the holes on the proto·board, but normal through hole capacitors also work well.

    Any additional details would help to know what kind of solution you need.· What is the Prop communicating with?· Can you·post a schematic·or picture of the curcuit you are presently using?

    Duane
  • PJAllenPJAllen Banned Posts: 5,065
    edited 2010-07-28 20:20
    This guy is way off in the weeds.

    http://forums.parallax.com/showthread.php?p=924737

    http://forums.parallax.com/showthread.php?p=925656
  • Jonathan HolleJonathan Holle Posts: 48
    edited 2010-07-28 20:24
    this kind of comment is not really necessary ; I'am just bad in electronic and would like a pcb with the 3 transistors, is this forum here for helping whose need help or for blaming us ?
  • LeonLeon Posts: 7,620
    edited 2010-07-28 20:27
    Someone designed one recently, and was selling them. I can't remember the details, though.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Leon Heller
    Amateur radio callsign: G1HSM
  • AntoineDoinelAntoineDoinel Posts: 312
    edited 2010-07-28 20:45
    Jonathan

    try·a look at this one:

    http://mikronauts.com/products/serplug/
    (maybe it's the same that Leon is referring to)

    It can be used for both comm and programming with a PC serial port.
    ·
  • LeonLeon Posts: 7,620
    edited 2010-07-28 21:11
    That's the one!

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Leon Heller
    Amateur radio callsign: G1HSM
  • Brian RileyBrian Riley Posts: 626
    edited 2010-07-28 21:16
    Leon said...
    Someone designed one recently, and was selling them. I can't remember the details, though.

    The Wulfden P1 is available at www.wulfden.org/TheShoppe/pa/index.shtml#P1 it is based upon a Parallax design from several years back when the Prop first came out. It works very reliably.

    P1-schem.jpg

    cheers ... BBR

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    cheers ... brian riley, n1bq, underhill center, vermont
    The Shoppe at Wulfden
    www.wulfden.org/TheShoppe/
    www.wulfden.org/TheShoppe/prop/ - Propeller Products
    www.wulfden.org/TheShoppe/k107/ - Serial LCD Display Gear
  • Duane DegnDuane Degn Posts: 10,588
    edited 2010-07-28 21:35
    Jonathan,
    I would have been nice if you had continued one of your original threads instead of starting a new one.· The other threads had pertinent information to understanding·your request for help.

    Brian,
    Thanks for the post.· I knew there was such a circuit·but I didn't know where to find it.

    Duane
  • SapiehaSapieha Posts: 2,964
    edited 2010-07-28 22:06
    Hi Jonathan Holle.

    Look on this page.


    mikronauts.com/products/serplug/

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Nothing is impossible, there are only different degrees of difficulty.
    For every stupid question there is at least one intelligent answer.
    Don't guess - ask instead.
    If you don't ask you won't know.
    If your gonna construct something, make it·as simple as·possible yet as versatile as posible.


    Sapieha
  • Jonathan HolleJonathan Holle Posts: 48
    edited 2010-07-30 20:55
    I finally bought a max3232 and the communication works fine. Thanks everybody for your help.
    But I got a problem when I load the program code in the eeprom, I got this message : "eeprom verify error", why ? when I load it to the ram, everything works fine...
  • SapiehaSapieha Posts: 2,964
    edited 2010-07-30 23:01
    Hi Jonathan Holle.

    If it is any board You build by You.
    Think that You need have Pull up Resistors on both traces from propeller to EEProm's I2C traces SD/SC and that them are correctly connected.

    Regards

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Nothing is impossible, there are only different degrees of difficulty.
    For every stupid question there is at least one intelligent answer.
    Don't guess - ask instead.
    If you don't ask you won't know.
    If your gonna construct something, make it·as simple as·possible yet as versatile as posible.


    Sapieha
  • Jonathan HolleJonathan Holle Posts: 48
    edited 2010-07-30 23:54
    I have connected WP, A0, A1, A2 to the vss ; SCL to P28 ; SDA to P29, VCC to VDD and two resistors of 10k between P28 & P29 to VDD , I think is ok ... I use a 24LC128, is this ok ? And the propeller got an internal eeprom, so it should work without the external one, isn't no ?
  • SapiehaSapieha Posts: 2,964
    edited 2010-07-31 00:00
    Hi Jonathan Holle.

    Propeller NOT have INTERNAL EEProm.

    256/512 EEProms have not any problem -- BUT - 128 are only half of what is needed. 128/8=16KB and You for correct functioning need at last 32KB EEProm.


    Regards

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Nothing is impossible, there are only different degrees of difficulty.
    For every stupid question there is at least one intelligent answer.
    Don't guess - ask instead.
    If you don't ask you won't know.
    If your gonna construct something, make it·as simple as·possible yet as versatile as posible.


    Sapieha
  • Dr_AculaDr_Acula Posts: 5,484
    edited 2010-07-31 01:03
    Re Sepieha "BUT - 128 are only half of what is needed. 128/8=16KB and You for correct functioning need at last 32KB EEProm."

    Well spotted!

    @Jonathan - you are getting very close now. Are you using sockets for the chips? If so, then it makes things much easier to change a chip like the eeprom.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    www.smarthome.viviti.com/propeller
  • Jonathan HolleJonathan Holle Posts: 48
    edited 2010-07-31 06:49
    Yep I'am using a socket :-D ... I will buy one 512 today. An other question, I'am afraid of my LM1086, If my power exceed 6v, the regulator go up to 3v3 ; how can I stabilize it ?
  • Dr_AculaDr_Acula Posts: 5,484
    edited 2010-07-31 08:16
    Re "I'am afraid of my LM1086"

    Hmm. Do you have some more information?

    The regulator should output 3.3V regardless of whether you give it 5V or 10V or 15V. That is, assuming you have a variable reg and have the two ressitors calculated correctly. Or do you have a fixed output one? If the output is varying, maybe it isn't wired up right. Can you post a photo/more information?

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    www.smarthome.viviti.com/propeller
  • Jonathan HolleJonathan Holle Posts: 48
    edited 2010-07-31 08:41
    It's the fix one, It is connected to the output of a 7805 with a 10uF tantalum between the output and the vss.
  • Dr_AculaDr_Acula Posts: 5,484
    edited 2010-07-31 08:48
    This is very confusing and it would help to have more information. What does the output of the 7805 do when you increase the input volts?

    I'm thinking that it is possible to wire up two regulators in series with the pins all muddled up and happen to get a bit of a voltage drop and so you think it is regulating but it is not. I think a photo would be very helpful at this stage.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    www.smarthome.viviti.com/propeller
  • Jonathan HolleJonathan Holle Posts: 48
    edited 2010-08-01 19:11
    When the power supply is between 5 to 6v I got 3,3v in the out of the lm1086 and when it's up to 6v, I got 3v3 to 4,5v ... please see the attached file
    tiff
    tiff
    alim.tiff
    28K
  • Duane DegnDuane Degn Posts: 10,588
    edited 2010-08-01 19:24
    Jonathan,

    Normally Vss and GND are the same thing; ground or 0V.· In you schematic, is your Vss supposed to be Vdd?
  • Jonathan HolleJonathan Holle Posts: 48
    edited 2010-08-01 19:41
    yes sorry ^^, I did a mistake
  • SapiehaSapieha Posts: 2,964
    edited 2010-08-01 20:11
    Hi Jonathan Holle.


    You NEED at last one 33-47uF Tantalum between Regulators (On Out trace from 5V to In to 3.3V)
    Normal one Tantalun and one 100nF in parallel
    And same on 3.3V Out.


    Regards

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Nothing is impossible, there are only different degrees of difficulty.
    For every stupid question there is at least one intelligent answer.
    Don't guess - ask instead.
    If you don't ask you won't know.
    If your gonna construct something, make it·as simple as·possible yet as versatile as posible.


    Sapieha
  • Jonathan HolleJonathan Holle Posts: 48
    edited 2010-08-03 20:04
    Is it ok like this ?
    tiff
    tiff
    alim.tiff
    28K
  • SapiehaSapieha Posts: 2,964
    edited 2010-08-03 20:22
    Hi Jonathan Holle.

    Look on my Picture.

    Regards

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Nothing is impossible, there are only different degrees of difficulty.
    For every stupid question there is at least one intelligent answer.
    Don't guess - ask instead.
    If you don't ask you won't know.
    If your gonna construct something, make it·as simple as·possible yet as versatile as posible.


    Sapieha
    alim xx.jpg
    1254 x 555 - 48K
  • Jonathan HolleJonathan Holle Posts: 48
    edited 2010-08-03 21:09
    thanks for your help, I will try tomorrow. I have an other question, with the propeller, six servos consume 10 A whereas when I was using a basic stamp with two parallax servo controller the consumption was 6 A for 18 servos ... Furthermore, when a group of servo is moving, the led I put on the vcc is going off, why ?
  • Dr_AculaDr_Acula Posts: 5,484
    edited 2010-08-03 23:57
    six servos consume 10 A

    Yikes, those are rather large servos.

    The load on a servo determines the current drain. No load might be tens of milliamps. But lifting a robot leg takes a lot more energy.

    I'm not surprised the led is going off - a 7805 regulator is only good for 1 amp.

    One way to solve this is to have two power supplies. Run the propeller off one supply (or battery). Use a different supply for the servos. Connect with a common ground. Servos came from the model plane world, and the standard supply for servos is four rechargeable batteries. Rechargeables can handle the peak load (10A if you need to) and you don't need a regulator for the servo supply, so no energy is being wasted as heat.

    And for the propeller, use your existing supply. If you only need 3V, then four batteries and a regulator will work fine. If you need a 5V supply as well, then you might need 6 batteries. But those ones can be smaller.

    The propeller supply can be wall-wart or battery. For the servo supply, four rechargeables can be more convenient than a 10 amp supply.

    With one supply you will find the microcontroller resets every time you move all the servos. Ballpark, I'm looking right now at a radio control car. A 9V battery to power the electronics. And six C batteries for the motors. The 9V might be 250mAH and the Cs are maybe 3AH. And the current draw is such that the Cs go flat before the electronics. So the motors just get slower when the battery is flat, rather than the electronics going haywire.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    www.smarthome.viviti.com/propeller

    Post Edited (Dr_Acula) : 8/4/2010 12:05:03 AM GMT
  • Jonathan HolleJonathan Holle Posts: 48
    edited 2010-08-04 07:34
    for the 5v supply I use a 78T05 (3A) and there is an other separate power supply for the servo connected to an atx power supply with ten 7805 connected in parallel. When I measure 10 A the robot is not supporting his weight (the body is raised). why servos consume more with the propeller than with the parallax servo controller ?
  • Dr_AculaDr_Acula Posts: 5,484
    edited 2010-08-04 10:16
    I don't know why the current consumption would be different.

    But "with ten 7805 connected in parallel."

    I'm not sure that is a good idea. Could you perhaps have one 7805 for two servos?

    Or - if it is an ATX supply, you would have regulated 5V available on one of the pins, so you should not need 7805 regulators at all?

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    www.smarthome.viviti.com/propeller
  • LeonLeon Posts: 7,620
    edited 2010-08-04 10:24
    Vss shouldn't be used on a schematic connection, it's the internal ground on a CMOS device (Voltage source, source). It definitely isn't a supply connection.

    ▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
    Leon Heller
    Amateur radio callsign: G1HSM
  • Duane DegnDuane Degn Posts: 10,588
    edited 2010-08-04 19:03
    Jonathan,

    An ATX power supply should make this problem easier to solve.· I'd think the servos should run fine off of the 5V line (red wires) of your power supply; no regulators need (most servos run fine at 5V).· You can also use the 3.3V (orange wire to run your Prop).· The ATX power supply I have has a sticker on the side stating how many amps are available at each voltage (35A for 3.3V and 5.0V on mine).· I'm using mine to power a Prop and a bunch of LEDs.· I think it works great.· Just make sure all your grounds are connected if you are use different power sources.

    Duane
Sign In or Register to comment.