Datasheet

© 2007 Microchip Technology Inc. DS39605F-page 175
PIC18F1220/1320
REGISTER 19-4: CONFIG3H: CONFIGURATION REGISTER 3 HIGH (BYTE ADDRESS 300005h)
REGISTER 19-5: CONFIG4L: CONFIGURATION REGISTER 4 LOW (BYTE ADDRESS 300006h)
R/P-1 U-0 U-0 U-0 U-0 U-0 U-0 U-0
MCLRE — — — — — — —
bit 7 bit 0
bit 7 MCLRE: MCLR
Pin Enable bit
1 =MCLR pin enabled, RA5 input pin disabled
0 = RA5 input pin enabled, MCLR
disabled
bit 6-0 Unimplemented: Read as ‘0’
Legend:
R = Readable bit P = Programmable bit U = Unimplemented bit, read as ‘0’
-n = Value when device is unprogrammed u = Unchanged from programmed state
R/P-1 U-0 U-0 U-0 U-0 R/P-1 U-0 R/P-1
DEBUG
— — — —LVP—STVR
bit 7 bit 0
bit 7 DEBUG
: Background Debugger Enable bit (see note)
1 = Background debugger disabled, RB6 and RB7 configured as general purpose I/O pins
0 = Background debugger enabled, RB6 and RB7 are dedicated to In-Circuit Debug
bit 6-3 Unimplemented: Read as ‘0’
bit 2 LVP: Low-Voltage ICSP Enable bit
1 = Low-Voltage ICSP enabled
0 = Low-Voltage ICSP disabled
bit 1 Unimplemented: Read as ‘0’
bit 0 STVR: Stack Full/Underflow Reset Enable bit
1 = Stack full/underflow will cause Reset
0 = Stack full/underflow will not cause Reset
Legend:
R = Readable bit C = Clearable bit U = Unimplemented bit, read as ‘0’
-n = Value when device is unprogrammed u = Unchanged from programmed state
Note: The Timer1 oscillator shares the T1OSI and T1OSO pins with the PGD and PGC
pins used for programming and debugging.
When using the Timer1 oscillator, In-Circuit Serial Programming (ICSP) may not
function correctly (high voltage or low voltage), or the In-Circuit Debugger (ICD) may
not communicate with the controller. As a result of using either ICSP or ICD, the
Timer1 crystal may be damaged.
If ICSP or ICD operations are required, the crystal should be disconnected from the
circuit (disconnect either lead) or installed after programming. The oscillator loading
capacitors may remain in-circuit during ICSP or ICD operation.