PIC16F87X
FIGURE 12-12: WAKE-UP FROM SLEEP THROUGH INTERRUPT
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
OSC1
(2)
TOST
CLKOUT(4)
INT pin
INTF flag
Interrupt Latency
(Note 2)
(INTCON<1>)
GIE bit
Processor in
SLEEP
(INTCON<7>)
INSTRUCTION FLOW
PC
PC
PC+1
PC+2
PC+2
PC + 2
0004h
0005h
Instruction
Inst(0004h)
Inst(PC + 1)
Inst(PC + 2)
Inst(0005h)
Inst(PC) = SLEEP
fetched
Instruction
executed
Dummy cycle
Dummy cycle
SLEEP
Inst(PC + 1)
Inst(PC - 1)
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.
12.14 In-Circuit Debugger
12.16 ID Locations
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. When the microcontrol-
ler has this feature enabled, some of the resources are
not available for general use. Table 12-7 shows which
features are consumed by the background debugger.
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.
TABLE 12-7: 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.
12.15 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.
1999 Microchip Technology Inc.
DS30292B-page 135
MICROCHIP [ MICROCHIP ]
