Testing against issues of hang from thread:
https://forum.pjrc.com/threads/59881-RawHID-recv()-hangs-after-updating-to-Teensyduino-1-4-9-or-higher-for-Teensy-4-0/page2

F_CPU -> F_CPU_ACTUAL

- trap unused memory regions
- trap nullptr
- trap stack overflow

Fix comment re: systick

fix EWM address

#define FLASHMEM

be compatible with teensy 4

update macro analogInputToDigitalPin

This answers a long standing question :-)

https://github.com/PaulStoffregen/cores/issues/424#issue-555760117

see RM V2 Page 3221

https://forum.pjrc.com/threads/59815-teensy-4-0-XBAR-questions?p=231803&viewfull=1#post231803

Added Contact Count to Teensy3 multi touch report

https://forum.pjrc.com/threads/59815-teensy-4-0-XBAR-questions

teensy3: usb_serial: Fix port 2/3 mismatch

The code for the second port was accidentally expanded into
usb_serial3.c, while the code for the third port was expanded in
usb_serial2.c.

Fixes: cd4c30fde5 ("Expand all USB serial 2 & 3 stuff (needed for Arduino IDE use)")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>

This reverts commit dc46850b68.

This reverts commit a0ea852ed0.

This reverts commit 6fb4c61b45.

This reverts commit 68b0b84c58.

Teensy3 usb triple serial

shiftout: highest speed 10MHz

Fixed analog comparators IRQ names.

T4.1 - Serial8 is on pins 34 and 35

It was defaulting to the same NUM_DIGITAL_PINS and NUM_ANALOG_INPUTS as the T4.0 so updated for the new pins

There are two pins on the SDCard IO pins that are valid alternate pins for Serial5
Serial5.setRX or setTX.

These pin numbers changed from T4 to T4.1 so update table depending on which board.

Serial8 is now defined for T4.1.

Previously it was defined for T4B1, but went away on T4B2 and released.  It is now defined on the T4.1