PIC16F870_13 Datasheet, PDF (101/172 Pages) Microchip Technology – 28/40-Pin, 8-Bit CMOS FLASH Microcontrollers

PIC16F870/871
FIGURE 11-11: WAKE-UP FROM SLEEP THROUGH INTERRUPT
OSC1
CLKO⁽⁴⁾
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1
INT pin
INTF Flag
(INTCON<1>)
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
TOST⁽²⁾
Interrupt Latency⁽²⁾
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
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 = 1024 TOSC (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: CLKO 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 pro-
grammed to a '0', the In-Circuit Debugger functionality
is enabled. This function allows simple debugging func-
tions when used with MPLAB^® ICD. When the micro-
controller has this feature enabled, some of the
resources are not available for general use. Table 11-8
shows which features are consumed by the
background debugger.
TABLE 11-8: DEBUGGER RESOURCES
I/O pins
RB6, RB7
Stack
1 level
Program Memory Address 0000h must be NOP
Last 100h words
Data Memory
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.
 2000-2013 Microchip Technology Inc.
DS30569C-page 101