PIC16F87 datasheet(147/230 Pages) MICROCHIP

147 / 230 page

 2002-2013 Microchip Technology Inc.

DS30487D-page 147

PIC16F87/88

15.14 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® ICD. When the

microcontroller has this feature enabled, some of the

resources are not available for general use. Table 15-7

shows which features are consumed by the background

debugger.

TABLE 15-7:

DEBUGGER RESOURCES

To use the In-Circuit Debugger function of the micro-

controller, the design must implement In-Circuit Serial

Programming connections to RA5/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.

15.15 Program Verification/Code

Protection

the

code

protection

bit(s)

have

not

been

programmed, the on-chip program memory can be

read out for verification purposes.

15.16 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

readable and writable during program/verify. It is

recommended that only the four Least Significant bits

of the ID location are used.

15.17 In-Circuit Serial Programming

PIC16F87/88 microcontrollers can be serially pro-

grammed while in the end application circuit. This is

simply done with two lines for clock and data and three

other lines for power, ground and the programming

voltage (see Figure 15-13 for an example). This allows

customers to manufacture boards with unprogrammed

devices and then program the microcontroller just

before shipping the product. This also allows the most

recent

firmware

custom

firmware

programmed.

For more information on serial programming, please

refer to the “PIC16F87/88 Flash Memory Programming

Specification” (DS39607).

FIGURE 15-13:

TYPICAL IN-CIRCUIT

SERIAL PROGRAMMING

CONNECTION

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

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.

External

Connector

Signals

To Normal

Connections

To Normal

Connections

PIC16F87/88

VDD

VSS

RA5/MCLR/VPP

RB6

RB7

+5V

VPP

CLK

Data I/O

VDD

* Isolation devices (as required).

† RB3 only used in LVP mode.

RB3†

RB3/PGM

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