PIC16F872_06 Datasheet, PDF (103/168 Pages) Microchip Technology – 28-Pin, 8-Bit CMOS Flash Microcontroller with 10-Bit A/D

PIC16F872
FIGURE 11-11: WAKE-UP FROM SLEEP THROUGH INTERRUPT
OSC1
CLKOUT⁽⁴⁾
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
TOST⁽²⁾
INT pin
INTF Flag
(INTCON<1>)
GIE bit
(INTCON<7>)
INSTRUCTION FLOW
PC
Instruction
Fetched
Instruction
Executed
PC
Inst(PC) = SLEEP
Inst(PC - 1)
PC+1
Inst(PC + 1)
SLEEP
Processor in
SLEEP
PC+2
Interrupt Latency
(Note 2)
PC+2
Inst(PC + 2)
Inst(PC + 1)
PC + 2
Dummy cycle
0004h
Inst(0004h)
Dummy cycle
0005h
Inst(0005h)
Inst(0004h)
Note 1: XT, HS or LP oscillator mode assumed.
2: TOST = 1024TOSC (drawing not to scale). This delay will not be there for RC osc mode.
3: GIE = '1' assumed. In this case, after wake- up, the processor jumps to the interrupt routine.
If GIE = '0', execution will continue in-line.
4: CLKOUT is not available in these osc modes, but shown here for timing reference.
11.14 In-Circuit Debugger
When the DEBUG bit in the configuration word is
programmed to a '0', the In-Circuit Debugger function-
ality is enabled. This function allows simple debugging
functions when used with MPLAB^® IDE. When the
microcontroller has this feature enabled, some of the
resources are not available for general use. Table 11-8
shows which features are consumed by the back-
ground debugger.
TABLE 11-8: DEBUGGER RESOURCES
I/O pins
Stack
Program Memory
Data Memory
RB6, RB7
1 level
Address 0000h must be NOP
Last 100h words
0x070 (0x0F0, 0x170, 0x1F0)
0x1EB - 0x1EF
To use the In-Circuit Debugger function of the micro-
controller, the design must implement In-Circuit Serial
Programming connections to MCLR/VPP, VDD, GND,
RB7 and RB6. This will interface to the In-Circuit
Debugger module available from Microchip or one of
the third party development tool companies.
11.15 Program Verification/Code
Protection
If the code protection bit(s) have not been pro-
grammed, the on-chip program memory can be read
out for verification purposes.
11.16 ID Locations
Four memory locations (2000h - 2003h) are designated
as ID locations, where the user can store checksum or
other code identification numbers. These locations are
not accessible during normal execution, but are read-
able and writable during program/verify. It is recom-
mended that only the 4 Least Significant bits of the ID
location are used.
© 2006 Microchip Technology Inc.
DS30221C-page 101