TB025

DS91025A-page 2

© 1998 Microchip Technology Inc.

FIGURE 1:

EECON1 REGISTER

HEX FILE FORMAT

The data to be programmed into program memory will

be read into the microcontroller using one of its stan-

Probably the simplest format to send the data to the

microcontroller is in the standard HEX format used by

the Microchip development tools. The formats sup-

ported are the Intel HEX Format (INHX8M), Intel Split

HEX Format (INHX8S), and the Intel HEX 32 Format

(INHX32). The most commonly used formats are the

INHX8M and INHX32 and therefore are the only for-

mats discussed in this document.

Please refer to

Appendix A in the MPASM User's Guide (DS33014) for

more information about HEX file formats. The differ-

ence between INHX8M and INHX32 is that INHX32

supports 32-bit addresses using a linear address

record. The basic format of the hex file is the same

between both formats as shown below:

:BBAAAATTHHHH...HHHHCC

Each data record begins with a 9 character prefix and

always ends with a 2 character checksum. All records

begin with a ':' regardless of the format. The individual

elements are described below.

• BB - is a two digit hexadecimal byte count repre-

senting the number of data bytes that will appear

on the line. Divide this number by two to get the

number of words per line.

• AAAA - is a four digit hexadecimal address repre-

senting the starting address of the data record.

Format is high byte first followed by low byte. The

address is doubled because this format only sup-

ports 8-bits (to find the real PICmicro address,

simply divide the value AAAA by 2).

• TT - is a two digit record type that will be '00' for

data records, '01' for end of file records and '04'

for extended address record (INHX32 only).

• HHHH - is a four digit hexadecimal data word. For-

mat is low byte followed by high byte. There will

be BB/2 data words following TT.

• CC - is a two digit hexadecimal checksum that is

the two's complement of the sum of all the pre-

ceding bytes in the line record.

Since the PIC16F87X devices only have a maximum of

8K words, the linear address record '04' is ignored by

the routine. The HEX file is composed of ASCII char-

acters 0 thorough 9 and A to F and the end of each line

has a carriage return and linefeed. The downloader

code in the PICmicro microcontrollers must convert the

ASCII characters to binary numbers to be used for pro-

gramming.

R/W-x

U-0

U-0

U-0

R/W-x

R/W-0

R/S-0

R/S-0

EEPGD —

—

—

WRERR WREN

WR

RD

R= Readable bit

W= Writable bit

S= Settable bit

U= Unimplemented bit,

read as ‘0’

- n= Value at POR reset

bit7

bit0

bit 7:

EEPGD: Program / Data EEPROM Select bit

1 = Accesses Program memory

0 = Accesses data memory

Note: This bit cannot be changed while a write operation is in progress.

bit 6:4:

Unimplemented: Read as '0'

bit 3:

WRERR: EEPROM Error Flag bit

1 = A write operation is prematurely terminated

(any MCLR reset or any WDT reset during normal operation)

0 = The write operation completed

bit 2:

WREN: EEPROM Write Enable bit

1 = Allows write cycles

0 = Inhibits write to the EEPROM

bit 1:

WR: Write Control bit

1 = initiates a write cycle.

The bit is cleared by hardware once write is complete.

The WR bit can only be set (not cleared) in software.

0 = Write cycle to the EEPROM is complete

bit 0:

RD: Read Control bit

1 = Initiates an EEPROM read (read takes one cycle)

RD is cleared in hardware. The RD bit can only be set (not cleared) in software.

0 = Does not initiate an EEPROM read