PIC18F23K20 datasheet(13/42 Pages) MICROCHIP

13 / 42 page

Advance Information

DS41297F-page 13

PIC18F2XK20/4XK20

3.0

DEVICE PROGRAMMING

Programming includes the ability to erase or write the

various memory regions within the device.

In all cases, except high-voltage ICSP Bulk Erase, the

EECON1 register must be configured in order to

operate on a particular memory region.

When using the EECON1 register to act on code

memory, the EEPGD bit must be set (EECON1<7> = 1)

and the CFGS bit must be cleared (EECON1<6> = 0).

The WREN bit must be set (EECON1<2> = 1) to

enable writes of any sort (e.g., erases) and this must be

done prior to initiating a write sequence. The FREE bit

must be set (EECON1<4> = 1) in order to erase the

program space being pointed to by the Table Pointer.

The erase or write sequence is initiated by setting the

WR bit (EECON1<1> = 1). It is strongly recommended

that the WREN bit only be set immediately prior to a

program or erase.

3.1

ICSP Erase

3.1.1

HIGH-VOLTAGE ICSP BULK ERASE

Erasing code or data EEPROM is accomplished by

configuring two Bulk Erase Control registers located at

3C0004h and 3C0005h. Code memory may be erased

portions at a time, or the user may erase the entire

device in one action. Bulk Erase operations will also

clear any code-protect settings associated with the

memory block erased. Erase options are detailed in

Table 3-1.

data

EEPROM

code-protected

(CPD = 0), the user must request an erase of data

EEPROM (e.g., 0084h as shown in Table 3-1).

TABLE 3-1:

BULK ERASE OPTIONS

The actual Bulk Erase function is a self-timed

operation. Once the erase has started (falling edge of

the 4th PGC after the NOP command), serial execution

will cease until the erase completes (parameter P11).

During this time, PGC may continue to toggle but PGD

must be held low.

The code sequence to erase the entire device is shown

in Table 3-2 and the flowchart is shown in Figure 3-1.

TABLE 3-2:

BULK ERASE COMMAND

SEQUENCE

FIGURE 3-1:

BULK ERASE FLOW

Description

Data

(3C0005h:3C0004h)

Chip Erase

0F8Fh

Erase User ID

0088h

Erase Data EEPROM

0084h

Erase Boot Block

0081h

Erase Config Bits

0082h

Erase Code EEPROM Block 0

0180h

Erase Code EEPROM Block 1

0280h

Erase Code EEPROM Block 2

0480h

Erase Code EEPROM Block 3

0880h

Note:

A Bulk Erase is the only way to reprogram

code-protect bits from an “on” state to an

“off” state.

4-Bit

Command

Data

Payload

Core Instruction

0000

0E 3C

MOVLW 3Ch

0000

6E F8

MOVWF TBLPTRU

0000

0E 00

MOVLW 00h

0000

6E F7

MOVWF TBLPTRH

0000

0E 05

MOVLW 05h

0000

6E F6

MOVWF TBLPTRL

1100

0F 0F

Write 0Fh to 3C0005h

0000

0E 3C

MOVLW 3Ch

0000

6E F8

MOVWF TBLPTRU

0000

0E 00

MOVLW 00h

0000

6E F7

MOVWF TBLPTRH

0000

0E 04

MOVLW 04h

0000

6E F6

MOVWF TBLPTRL

1100

8F 8F

Write 8F8Fh TO 3C0004h

to erase entire device.

0000

00 00

NOP

0000

00 00

Hold PGD low until erase

completes.

Start

Done

Write 8F8Fh to

3C0004h to Erase

Entire Device

Write 0F0Fh

Delay P11 + P10

Time

to 3C0005h

PIC18F23K20 Arkusz danych(PDF) 13 Page - Microchip Technology

PIC18F23K20 Arkusz danych(HTML) 13 Page - Microchip Technology

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42

Arkusz danych Pobierz

Link URL