https://github.com/LDmicro/LDmicro/releases/tag/4.1.5
== Release 4.1.5

The functionality of this release was developed as a result of discussion on the page
http://cq.cx/ladder-forum.pl?action=viewthread&parent=6006
and gives ability to use the watchdog timer (WDT) on PIC and AVR.
See https://en.wikipedia.org/wiki/Watchdog_timer

There is some difference of WDT in PIC and AVR with respect to LDmicro.

LDmicro not sets fuses in HEX file for AVR. Remember to set the AVR processor
configuration (fuses) correctly using your programmer (eg. AVRISP) and
software (eg. AVRDUDE).
You can manipulate WTDON to enable/disable watchdog timer. See
http://www.engbedded.com/fusecalc

LDmicro sets CONFIGURATION WORD REGISTERS (CONFIG, CONFIG1, CONFIG2)
in HEX file for PIC. WDT is disabled by default.
CONFIG bit WDTE: Watchdog Timer Enable bit is setted to 0 = WDT is disabled.
But you can enable it with your programmer(eg. PICKIT, USBPICPROG).
Also you can enable it inside LDmicro in 'PLC Configurations' dialog using
'WDT enable' checkbox (has sense for PIC).

* New: 'WDT enable' checkbox added in 'PLC Configurations' dialog.

ALL versions of LDmicro executes CLRWDT command "Watchdog reset"
every PLC cycle (at begin of the cycle) regardless WDT enabled or disabled.

If WDT enabled, the WDT has a nominal time-out period of 16.3 - 18 ms
(with no prescaler) or more. So, if you need PLC cycle period more
then WDT period you must use CLRWDT command inside PLC cycle.

* New: CLRWDT element to clear WDT timer implemented.

* New: LOCK element is implemented. LOCK command is an artificial
situation to provocation the WDT reset (if WDT enabled). LOCK command
designed as infinite loop. It is deadlock, way to freeze, blockade the
program.
LOCK command executes goto to the current address, i.e.
labelN: goto labelN (label02e7: rjmp label02e7), i.e. infinite loop.
LOCK command executes the infinite loop, but WDT can reset the MCU.
Only WDT or external reset can unfreeze the program after LOCK command.

* Updated: SLEEP operation works at all MCU.
The SLEEP (Power-down) mode is used for power saving on battery supply.

PIC: Wake-up from sleep owing to external interrupt on rising edge of RB0/INT pin.
PIC10xxxx: Wake-up from sleep on pin change GP0, GP1, GP3.
AVR: Wake-up from sleep owing to external interrupt on rising edge of PD2/INT0, PD3/INT1 pins.
SLEEP operation don't affect MCU IO pins and others LDmicro operations.
Note: SLEEP lengthens the PLC cycle time and timers TON, TOF, RTO, CTY.
This can frustrate the plans, break the flow of work.

* New: In addition to variable name that begins with symbol '#' like
#PINA, #PINB, ... treated as 8bit (byte) input port,
#PORTA, #PORTB, ... treated as 8bit (byte) output port,
#TRISA, #TRISB, ... treated as 8bit (byte) data direction register of corresponding port,
added immediate address hardware registers access
#0x8E, #5, ... treated as 8bit the (byte) hardware register with this address.
Be careful with writing to the hardware registers.
See how to use PCON register (address 0x8E) to determine the cause of
the PIC16F628 reset in the next wiki link.

* Wiki: Addition 3. WDT, LOCK, SLEEP operation is tested at PIC16F628.
https://github.com/LDmicro/LDmicro/wiki/SLEEP-example