Cypress Semiconductor CY7C292A Manual de usuario descargar pdf (Pagina 31)

Start Address Record (MCS-86 hex format)

Byte Number

1 Colon (:)

2—3 Record length, “04"

4—7 “0000"

8—9 Record type, “03"

10—13 8086 CS value

14—17 8086 IP value

18—19 Check sum

20—21 CR, LF

The checksum is the two’s compliment of the 8-bit sum, without carry,

of all the data bytes, the two bytes in the load address, and the byte

count.

Example:

:03012300010203D3

In the above example add 3 + 1 + 23h + 0 + 1 + 2 + 3 = 2Dh. The

total of the above bytes is 2Dh. If you do a two’s compliment on the

number the result is D3h which, you will notice is the checksum. A

simple visual way of doing this is to write the number in binary, then

invert each bit. After you do that, add 1 to it and that is the checksum:

00101101 = 2D

11010010 = D2 (inversion or negation)

+1 = add 1 for 2’s compliment

11010011 = 2’s compliment checksum.

Chapter 7 Hex Formats Model 9000

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Cypress Semiconductor CY7C292A Manual de usuario Pagina 31