Forum Rule: Always post complete source code & details to reproduce any issue!
Results 1 to 6 of 6

Thread: Buydisplay 7" RA8875 ft5206 800 x 480 display jumper re-configuration

  1. #1
    Member
    Join Date
    Apr 2020
    Location
    Guelph Ontario Canada
    Posts
    86

    Buydisplay 7" RA8875 ft5206 800 x 480 display jumper re-configuration

    I received the above display in the title ..but missed the proper configuration ..though it came configured for spi ,but jumpers are set up for 8080....I can re-do the jumpers , but there is a requirement for 3 x 10k surface mount resistors ..I can solder them ,but I don't know what series/size they are physically. If a member on here has one of these displays and is familiar with smd components ..could they point me in the right direction for getting these smd parts? Thanks ..

  2. #2
    Senior Member
    Join Date
    Feb 2015
    Location
    Finland
    Posts
    224
    Are you talking about this one, or some other module?
    EastRising/BuyDisplay has a LOT of different modules, so it is very important to be precise about which product you're talking about.

  3. #3
    Member
    Join Date
    Apr 2020
    Location
    Guelph Ontario Canada
    Posts
    86
    Yes ..thats the panel , sorry I should have posted up the model I ..I need 3 x 10k for r1/r2/r3 on the top left of the board ..I just don't know the component size 1206/0805 ?

  4. #4
    Senior Member
    Join Date
    Feb 2015
    Location
    Finland
    Posts
    224
    You'll want the 4-wire serial mode (easier SPI mode, with Chip Select (CS), Data (MOSI/DO), Clock (CLK), and the fourth pin is a generic I/O pin that determines Command/Data mode), right?

    For jumpers 9-16, you short the even ones and open the odd ones (short J10, J12, J14, J16; open J9, J11, J13, J15).
    You also need 10kOhm resistors at R1, R2, R3; 0Ohm resistors (shorts) at R35, R36, R37, R38; and leave R39, R40, R41, and R42 unpopulated.

    The resistors that are used to determine the mode are R1, R2, R3, R35, R36, R37, R38, R39, R40, R41, R42.
    BuyDisplay/EastRising says they put 0R resistors (shorts, or links; they do look like normal resistors, but have a 0 on them) at R39, R40, R41, R42, and leave R35, R36, R37, R38 unpopulated.

    Looking at the pictures, the resistors look like 0805 size. You can verify that by measuring the existing resistors with calipers in millimeters:
    1.0 mm 0.5 mm = 0402
    1.55 mm 0.85mm = 0603
    2.0 mm 1.2 mm = 0805
    In inches, 0402 is 0.04"0.02"; 0603 is 0.06"0.02"; and 0805 is 0.08"0.05". Measuring the length of the resistor itself suffices, and you don't even need to be very precise.

    I recommend getting an SMD Resistor Sample Book. They contain a bunch of different SMD resistors in different sizes, and come in handy in a situation like this. Otherwise, you need one 0Ohm resistor/link and three 10kOhm resistors in the existing size; get 10 of both to be sure.

    The resistor positions are marked on the board. R1, R2, R3 are the three leftmost ones in the group of four near the upper left corner of the board, and R35-R42 are below those in a group of 8 resistors, two columns by four rows, directly right of the widest connector.

    So, what you need to do, is remove R1, R2, R3, and replace them with 10 kOhm resistors.
    The three 0Ohm resistors, and an additional one, you put at R35, R36, R37, R38 (the column of four resistors nearest to the widest connector). The other four, R39, R40, R41, R42 you leave unpopulated.

  5. #5
    Member
    Join Date
    Apr 2020
    Location
    Guelph Ontario Canada
    Posts
    86
    Quote Originally Posted by Nominal Animal View Post
    You'll want the 4-wire serial mode (easier SPI mode, with Chip Select (CS), Data (MOSI/DO), Clock (CLK), and the fourth pin is a generic I/O pin that determines Command/Data mode), right?

    For jumpers 9-16, you short the even ones and open the odd ones (short J10, J12, J14, J16; open J9, J11, J13, J15).
    You also need 10kOhm resistors at R1, R2, R3; 0Ohm resistors (shorts) at R35, R36, R37, R38; and leave R39, R40, R41, and R42 unpopulated.

    The resistors that are used to determine the mode are R1, R2, R3, R35, R36, R37, R38, R39, R40, R41, R42.
    BuyDisplay/EastRising says they put 0R resistors (shorts, or links; they do look like normal resistors, but have a 0 on them) at R39, R40, R41, R42, and leave R35, R36, R37, R38 unpopulated.

    Looking at the pictures, the resistors look like 0805 size. You can verify that by measuring the existing resistors with calipers in millimeters:
    1.0 mm 0.5 mm = 0402
    1.55 mm 0.85mm = 0603
    2.0 mm 1.2 mm = 0805
    In inches, 0402 is 0.04"0.02"; 0603 is 0.06"0.02"; and 0805 is 0.08"0.05". Measuring the length of the resistor itself suffices, and you don't even need to be very precise.

    I recommend getting an SMD Resistor Sample Book. They contain a bunch of different SMD resistors in different sizes, and come in handy in a situation like this. Otherwise, you need one 0Ohm resistor/link and three 10kOhm resistors in the existing size; get 10 of both to be sure.

    The resistor positions are marked on the board. R1, R2, R3 are the three leftmost ones in the group of four near the upper left corner of the board, and R35-R42 are below those in a group of 8 resistors, two columns by four rows, directly right of the widest connector.

    So, what you need to do, is remove R1, R2, R3, and replace them with 10 kOhm resistors.
    The three 0Ohm resistors, and an additional one, you put at R35, R36, R37, R38 (the column of four resistors nearest to the widest connector). The other four, R39, R40, R41, R42 you leave unpopulated.
    Good Idea on the SMD sample kit I was not thinking of that .. I'm good on what has to be done .. I have other buy display screens that are SPI now so familiar with 4 wire setup on my teensy 4.0 and 4.1 . Just i didn't scroll down the screen when I grabbed it off ebay only to realize it was configured for an 8080 .. outside of that I'm fine with these displays (with the exception of the touchscreen on the 5" since they went to a gsl1680F revision , I have yet to get that going properly) ..anyhow .. Thankyou for the response . I don't own a set of calipers but I can borrow off my bud and measure the R's up.. Thankyoiu for your time!

  6. #6
    Senior Member
    Join Date
    Feb 2015
    Location
    Finland
    Posts
    224
    You're welcome!

    And sorry, I didn't realize you only needed to know the resistor sizes. Me fail English...

    Another option is to contact BuyDisplay/EastRising at https://www.buydisplay.com/contact/, and ask them the resistor R1-R42 sizes. Just remember to link the exact board you are using!
    They might even edit their documentation to specify the resistor sizes there, which would help everyone.

    (It is one of the rare Asian firms that has realized the importance of their documentation, and seem to put some real effort behind theirs. They're obviously taken a look at how Adafruit and SparkFun do it, and know it makes them stand out. I've already bought a few of their ISP displays, a couple of display modules, and even a couple of their ePaper modules just because they have the full documentation! Also, I do have contacted them once before, and they did respond and were very helpful; but I took care to be brief and clear, with all specifics of the situation [because I know how difficult it is to work with just partial information, especially in an end-user facing role].)

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •