Teensy 3.5 & Teensy 3.6 do not work at clock speeds above 96MHz

[sbfreddie]

Using Teensy 3.5 clocked above 96 MHz does not work, I suspected you will need to adjust the SPI clock for the higher clock speeds of Teensy 3.5 and Teensy 3.6.

Thanks, Ed

[bossredman]

Hi,

I'm currently trying to get my project to complie with a 3.6 -but it fails for compatiblilty issues with the RA8875 tft = RA8875(RA8875_CS2, RA8875_RESET); line.

I see the library only states support for TEENSY 3, TEENSY 3.1, TEENSY 3.2, TEENSY LC and so looks like the library detects it as a Generic Arm.

Did you have have to mod the library in any way to get yours to work?

[sbfreddie]

I don't have any problems compiling RA8875 with the Teensy 3.5 or the 3.6's. I use embedXcode with Xcode on my Mac's. There is a problem trying to build the fonts as the Xcode compiler is different from the compiler used in Arduino. I just remove the font folder and it builds with no errors. Perhaps you are not using his latest branch:

0.70b11p10 changes...

Added initial support for incoming Teensy's Some changes from MrTom accepted, should fix an hardware bug in trianles and some other minor things Created _includes folder and moved from settings some file that should never change, this will help users to save their settings between updates.

In June he added the changes for Teensy 3.5 and Teensy 3.6.

Thanks, Ed

[Zuntara]

I can confirm that this library works on teensy 3.5 However with a couple of sidenotes:

• I had to turn on the backlight explicitly to see something, the examples do not toggle the backscreen to 'on' it seems.
• I also had to use the alternative SPI pins on teensy 3.5 - this also works with the SDIO for the SDCard slot located on the teensy device.

#define RA8875_MOSI         7
#define RA8875_MISO         8
#define RA8875_SCK          14
#define RA8875_CS           15  

SPI.setMISO(RA8875_MISO);
SPI.setMOSI(RA8875_MOSI);
SPI.setSCK(RA8875_SCK);
SPI.setCS(RA8875_CS);

[ghost]

I have the 5" and 7" resistive displays working with Teensy 3.6. The code required this change:

define RA_CS 21 //out

define RA_RST 28 //out

define RA_INT 24 //in

define RA_MOSI 7

define RA_SCK 14

RA8875 tft = RA8875(RA_CS, RA_RST, RA_MOSI, RA_SCK);

However, I am having an issue with "double-touching"...the code seems to buffer the touch and execute the code twice. I read that a delay(500) followed by a call: touched(false) will stop this. Someone else suggested that slowing down the SPI interface is necessary. I have not played with the library enough yet to know if there is a method call for that. Other ways to slow the SPI interface??