Forum Rule: Always post complete source code & details to reproduce any issue!
Results 1 to 11 of 11

Thread: ILI9341 touch - SD Slot

  1. #1
    Senior Member+ Frank B's Avatar
    Join Date
    Apr 2014
    Location
    Germany NRW
    Posts
    5,565

    ILI9341 touch - SD Slot

    Hi,
    has anyone tried to use the SD Slot on a ILI9341 display, without removing the resistors (Teenssy 3.x)?
    Just asking before I try this and spend time for nothing.
    It would be OK if it is slow - I don't need speed in this case (20kB/second is more than needed)- but does it work?

  2. #2
    Junior Member
    Join Date
    Dec 2016
    Posts
    4
    Why no try it an external 3v3 SD reader like this:


  3. #3
    Senior Member+ defragster's Avatar
    Join Date
    Feb 2015
    Posts
    8,327
    Hi Frank - saw your post - I used that once - still have the (poorly done) protoboard ILI9341 adapter here on my desk with the wires to feed the end pin holes on a display. Not sure if that was with resistors removed?

    I'm assuming this is looking to get SD on a project that used to use a T_3.6 without adding an SD adapter?

    But I'm not sure which display I used that with - the ones marked #3 and #4 on my desk are unmodified. I know I got one that went all white and closing the J1 jumper made that work and that one may be the one I used that - and it seems I pulled the resistors off of it as well.

    I don't know where #1 and #2 are at the moment - That would be back 2+ years when I was working on Touch - not sure if I left useful notes about that in a post ...

  4. #4
    Senior Member+ defragster's Avatar
    Join Date
    Feb 2015
    Posts
    8,327
    Frank I found this note from Paul Oct 11/ 2015 :
    Quote Originally Posted by PaulStoffregen View Post
    ...

    Yes, but at least the one I have here seems to have 1K series resistors. Those will need to be shorted to allow 24 MHz SPI.

    ...

  5. #5
    Senior Member+ Frank B's Avatar
    Join Date
    Apr 2014
    Location
    Germany NRW
    Posts
    5,565
    Less MHz would be OK. But I need long filenames.
    I'll try it this weekend..
    It is for a project with a Display but without Audioshield or a Teensy with inbuilt SD. And since the display has a slot anyway, and the project needs to load only a few (32) KByte at startup (and some kb later on userrequest) it would be the simplest solution - as long the loading takes not longer than 1-2 seconds. I do not want any fiddling with the display-resistors - it would be too annoying for other users.
    LFN: I guess I need Bill's lib, then. Does it support setting to low clocks? How?

  6. #6
    Senior Member+ defragster's Avatar
    Join Date
    Feb 2015
    Posts
    8,327
    For SDFat? see :: github.com/greiman/SdFat/blob/.../changes.txt

    This might point the way … or #define SD_SCK_HZ(maxSpeed) SPISettings(maxSpeed, MSBFIRST, SPI_MODE0):
    Code:
    #define SD_SCK_MHZ(maxMhz) SPISettings(1000000UL*maxMhz, MSBFIRST, SPI_MODE0)
    // SPI divisor constants
    
    /** Set SCK to max possible rate. */
    #define SPI_FULL_SPEED SD_SCK_MHZ(50)
    
    /** Set SCK rate to F_CPU/3 for Due */
    #define SPI_DIV3_SPEED SD_SCK_HZ(F_CPU/3)
    
    /** Set SCK rate to F_CPU/4. */
    #define SPI_HALF_SPEED SD_SCK_HZ(F_CPU/4)
    Though it seems pretty simple to have a hot iron and solder blob (flux?) to wipe those right off - then put solder over the gap?

  7. #7
    Senior Member+ Frank B's Avatar
    Join Date
    Apr 2014
    Location
    Germany NRW
    Posts
    5,565
    great, thank you.

  8. #8
    Senior Member
    Join Date
    Jul 2014
    Posts
    2,146
    Quote Originally Posted by Frank B View Post
    great, thank you.
    For the time being only T3
    need to wait for T4 until Bill is porting library

  9. #9
    Senior Member+ Frank B's Avatar
    Join Date
    Apr 2014
    Location
    Germany NRW
    Posts
    5,565
    If needed I'll do the porting. Maybe I'll use software-spi/bigbang on some free pins.. that would allow adjusting the speed, too. still undecided it is for the next generation of my c64 emu with t4.. mainly to load alternative ROMs and..the diskdrive emu (the drive is slow anyway), maybe. this way it would be easier to assemble, and less parts.

  10. #10
    Senior Member
    Join Date
    Jul 2014
    Posts
    2,146
    Quote Originally Posted by Frank B View Post
    If needed I'll do the porting.
    I started porting, but then I saw that Bill was on the list of receiving T4, so I decided to wait.

  11. #11
    Senior Member+ Frank B's Avatar
    Join Date
    Apr 2014
    Location
    Germany NRW
    Posts
    5,565
    Quote Originally Posted by WMXZ View Post
    I started porting, but then I saw that Bill was on the list of receiving T4, so I decided to wait.
    Looks like with Software-SPI, it can reach 23KB/s (had to insert loong delays).. not that much But even that is 2x the speed of the fastest C64 "fast"-loaders Original speed was about 400Bytes/Second..

    Ok, works.

Posting Permissions

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