Similar startup delay code between Teensy 3 and 4

PaulStoffregen · Jul 27, 2022 · 4e35529 · 4e35529
1 parent d44e8bb
commit 4e35529
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Showing 2 changed files with 15 additions and 5 deletions.
diff --git a/teensy3/pins_teensy.c b/teensy3/pins_teensy.c
@@ -599,9 +599,9 @@ void _init_Teensyduino_internal_(void)
  // https://forum.pjrc.com/threads/31290-Teensey-3-2-Teensey-Loader-1-24-Issues?p=87273&viewfull=1#post87273
 
  startup_middle_hook();
- delay(TEENSY_INIT_USB_DELAY_BEFORE);
+ while (millis() < TEENSY_INIT_USB_DELAY_BEFORE) ; // wait
  usb_init();
- delay(TEENSY_INIT_USB_DELAY_AFTER);
+ while (millis() < TEENSY_INIT_USB_DELAY_AFTER + TEENSY_INIT_USB_DELAY_BEFORE) ; // wait
 }
 
 

diff --git a/teensy4/startup.c b/teensy4/startup.c
@@ -146,10 +146,20 @@ void ResetHandler(void)
  pwm_init();
  tempmon_init();
  startup_middle_hook();
- while (millis() < 20) ; // wait at least 20ms before starting USB
- usb_init();
 
- while (millis() < 300) ; // wait at least 300ms before calling user code
+#if !defined(TEENSY_INIT_USB_DELAY_BEFORE)
+ #define TEENSY_INIT_USB_DELAY_BEFORE 20
+#endif
+#if !defined(TEENSY_INIT_USB_DELAY_AFTER)
+ #define TEENSY_INIT_USB_DELAY_AFTER 280
+#endif
+ // for background about this startup delay, please see these conversations
+ // https://forum.pjrc.com/threads/36606?p=113980&viewfull=1#post113980
+ // https://forum.pjrc.com/threads/31290?p=87273&viewfull=1#post87273
+
+ while (millis() < TEENSY_INIT_USB_DELAY_BEFORE) ; // wait
+ usb_init();
+ while (millis() < TEENSY_INIT_USB_DELAY_AFTER + TEENSY_INIT_USB_DELAY_BEFORE) ; // wait
  //printf("before C++ constructors\n");
  startup_late_hook();
  __libc_init_array();