PIC18F1XK22 Datasheet, PDF (272/388 Pages) Microchip Technology – 20-Pin Flash Microcontrollers with nanoWatt XLP Technology

PIC18F1XK22/LF1XK22
22.2.1 CONTROL REGISTER
Register 22-14 shows the WDTCON register. This is a
readable and writable register which contains a control
bit that allows software to override the WDT enable
Configuration bit, but only if the Configuration bit has
disabled the WDT.
REGISTER 22-14: WDTCON: WATCHDOG TIMER CONTROL REGISTER
U-0
—
bit 7
U-0
U-0
U-0
U-0
U-0
—
—
—
—
—
U-0
R/W-0
—
SWDTEN⁽¹⁾
bit 0
Legend:
R = Readable bit
-n = Value at POR
W = Writable bit
‘1’ = Bit is set
U = Unimplemented bit, read as ‘0’
‘0’ = Bit is cleared
x = Bit is unknown
bit 7-1
bit 0
Unimplemented: Read as ‘0’
SWDTEN: Software Enable or Disable the Watchdog Timer bit⁽¹⁾
1 = WDT is turned on
0 = WDT is turned off (Reset value)
Note 1: This bit has no effect if the Configuration bit, WDTEN, is enabled.
TABLE 22-2: SUMMARY OF WATCHDOG TIMER REGISTERS
Name
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Reset
Values
on page
CONFIG2H
—
—
— WDTPS3 WDTPS2 WDTPS1 WDTPS0 WDTEN 265
RCON
IPEN SBOREN —
RI
TO
PD
POR
BOR
258
WDTCON
—
—
—
—
—
—
— SWDTEN 258
Legend: — = unimplemented, read as ‘0’. Shaded cells are not used by the Watchdog Timer.
22.3 Program Verification and
Code Protection
The overall structure of the code protection on the
PIC18 Flash devices differs significantly from other
PIC^® microcontroller devices.
The user program memory is divided into five blocks.
One of these is a boot block of 0.5K or 2K bytes,
depending on the device. The remainder of the mem-
ory is divided into individual blocks on binary boundar-
ies.
Each of the five blocks has three code protection bits
associated with them. They are:
• Code-Protect bit (CPn)
• Write-Protect bit (WRTn)
• External Block Table Read bit (EBTRn)
Figure 22-2 shows the program memory organization
for 8, 16 and 32-Kbyte devices and the specific code
protection bit associated with each block. The actual
locations of the bits are summarized in Table 22-3.
DS41365D-page 272
Preliminary
 2010 Microchip Technology Inc.