I'm trying to use the lcd on a teensy 3.6. The max clock speed is 180MHz. The lcd works fine, using the SPI interface, until the CPU is set above 72MHz. At 96MHz(the next speed up) characters are constantly being printed in what appears to be random locations. At 180MHz the screen stays off.
I think the problem is in the library. Maybe the code is being processed too fast at higher clock speeds? In the spiTransfer function there is a delay for the execution time of the command so I'm not sure how that could be the issue.
#include <DogLcd.h>
// initialize the library with the numbers of the interface pins
DogLcd lcd(32, 31, 29, 30);
void setup() {
// set up the LCD type and the contrast setting for the display
lcd.begin(DOG_LCD_M162,32,DOG_LCD_VCC_3V3);
// Print a message to the LCD.
lcd.print("hello, world!");
}