PIC16F688-ESLASHST datasheet(76/174 Pages) MICROCHIP

76 / 174 page

PIC16F688

DS41203B-page 74

Preliminary

 2004 Microchip Technology Inc.

9.1.4

READING THE FLASH PROGRAM

MEMORY

To read a program memory location, the user must

write two bytes of the address to the EEADR and

EEADRH registers, set the EEPGD control bit

(EECON1<7>),

and

then

set

control

bit

(EECON1<0>). Once the read control bit is set, the

program memory Flash controller will use the second

instruction cycle to read the data. This causes the

second instruction immediately following the “BSF

EECON1,RD

”

instruction to be ignored. The data is

available in the very next cycle, in the EEDAT and

EEDATH registers; therefore, it can be read as two

bytes in the following instructions.

EEDAT and EEDATH registers will hold this value until

another read or until it is written to by the user (during

a write operation).

EXAMPLE 9-3:

FLASH PROGRAM READ

Note 1: The two instructions following a program

memory read are required to be NOP’s.

This prevents the user from executing a

two-cycle

instruction

the

instruction after the RD bit is set.

2: If the WR bit is set when EEPGD = 1, it

will be immediately reset to ‘0’ and no

operation will take place.

BSF

STATUS, RP0

;

BCF

STATUS, RP1

; Bank 1

MOVLW

MS_PROG_EE_ADDR

;

MOVWF

EEADRH

; MS Byte of Program Address to read

MOVLW

LS_PROG_EE_ADDR

;

MOVWF

EEADR

; LS Byte of Program Address to read

BSF

EECON1, EEPGD

; Point to PROGRAM memory

BSF

EECON1, RD

; EE Read

;

; First instruction after BSF EECON1,RD executes normally

NOP

; Any instructions here are ignored as program

; memory is read in second cycle after BSF EECON1,RD

;

MOVF

EEDAT, W

; W = LS Byte of Program EEDAT

MOVF

EEDATH, W

; W = MS Byte of Program EEDAT

PIC16F688-E/ST Datasheet(PDF) 76 Page - Microchip Technology

PIC16F688-E/ST Datasheet(HTML) 76 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 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Download

Link URL