 2002 Microchip Technology Inc.

Preliminary

DS39588A-page 5

PIC16F72

2.3.1.1

Load Configuration

After receiving the Load Configuration command, the

PC will be set to 0x2000 and the data sent with the

command is discarded. The four ID locations and the

configuration word can then be programmed using the

normal programming sequence, as described in

Section 2.3. A description of the memory mapping

schemes of the program memory for normal operation

and Configuration mode operation is shown in

Figure 2-1. After the configuration memory is entered,

the only way to get back to the user program memory

is to exit the Program/Verify Test mode by taking MCLR

low.

2.3.1.2

Load Data for Memory

The device will load in a 14-bit “data word” when 16

cycles are applied, as described previously. A timing

diagram for the load data command is shown in

Figure 5-1.

2.3.1.3

Read Data from Memory

The device will transmit data bits out of the memory

(program or configuration) currently addressed by the

PC, starting with the second rising edge of the clock

input. RB7 will go into Output mode on the second ris-

ing clock edge and will revert back to Input mode

(hi-impedance) after the 16th rising edge. A timing dia-

gram for this command is shown in Figure 5-2.

If the device is code protected, user program memory

will read all ‘0’s. Configuration memory can still be read.

2.3.1.4

Increment Address

The PC is incremented by one. A timing diagram for

this command is shown in Figure 5-3.

2.3.1.5

Begin Programming

A ‘Load Data’ command must be issued before

every ‘Begin Programming’ command. Program-

ming of memory (configuration or program) will begin

after this command is received and decoded. Program-

ming requires (tprog) time and is terminated using an

‘End Programming’ command.

2.3.1.6

Chip Erase (Program Memory)

Erasure of configuration and program memory begins

after this command is received and decoded. The

erase sequence is self-timed and it is not necessary to

issue an ‘End Programming’ command, only to wait for

the appropriate time interval (tera) for the entire erase

sequence, before issuing another command.

This procedure will disable code protection (code pro-

tect bit = 1); however, all data within the program mem-

ory will be erased when this command is executed and

thus, the security of the data or code is not

compromised.

2.4

Programming Algorithm Requires

The PIC16F72 uses an intelligent algorithm, which

The actual chip erase and programming must be done

Since Microchip may introduce future versions of the

these levels are user selectable (defaults are OK).

Note:

All CHIP ERASE operations must take

Note:

Any programmer not meeting this require-

ment may only be classified as a “proto-

type” or “development” programmer, but

not a “production quality” programmer.