86FS27-21

2007-08-07

TMP86FS27

2.8

Error Code

When the device detects an error, the error codes are sent to the controller.

2.9

Checksum (SUM)

(1) Calculation method

SUM consists of byte

+ byte.... + byte, the checksum of which is returned in word as the

result.

Namely, data is read out in byte and checksum of which is calculated, with the result

returned in word.

Example:

The SUM returned when executing the flash memory write command, RAM

loader command, or flash memory SUM command is calculated in the manner

shown above.

(2) Calculation data

The data from which SUM is calculated are listed in Table 2.9.1 below.

Table 2.9.1 Checksum Calculation Data

Transmit Data

Meaning of Transmit Data

62H, 62H, 62H

Baud rate modification error occurred.

63H, 63H, 63H

Operating command error occurred.

A1H, A1H, A1H

Framing error in received data occurred.

A3H, A3H, A3H

Overrun error in received data occurred.

A1H

If the data to be calculated consists of the four bytes shown to the

left, SUM of the data is

B2H

A1H

+ B2H + C3H + D4H = 02EAH

SUM (HIGH)

= 02H

SUM (LOW)

= EAH

C3H

D4H

Operating Mode

Calculation Data

Remarks

Flash memory writing mode

Data in the entire area (60 Kbytes) of flash

memory

Even when written to part of the flash memory area,

data in the entire memory area (60 Kbytes) is

calculated.

The length of data, address, record type and

checksum in Intel Hex format are not included in SUM.

Flash memory Checksum output

mode

RAM loader mode

Data written to RAM

The length of data, address, record type and

checksum in Intel Hex format are not included in SUM.

Product discrimination code out-

put mode

Checksum of transferred data (from 9th to

18th byte)

For details, refer to “2.6.4 Product Discrimination

Code Output Mode”.