Epson V7 User Manual

Ser

Data is added up (SUM), and the lower one byte (8 bits) of the sum is converted into the 
2-digit ASCII code (hexadecimal).  A sum check code is shown below.

Example: Transmission mode: without CR/LF, with sum check

Command: 20 

(data 

read)

Address:

10 words from $u1000 (03E8H)

When reading, a sum check will be performed as shown below.

[ACK]

This code is received at normal termination.
00H

(3030:  ASCII)

[NAK]

This code is received at abnormal termination.  (ASCII)  Refer to the next page for more 
information.

02H:

Overrun/Framing error
An overrun or framing error is detected in the received data.  Send the command 
again.

03H:

Parity error
A parity error is detected in the received data.  Send the command again.

04H:

Sum check error
A sum error occurs with the received data.

06H:

Count error
The memory read/write count is “0.”

0FH:

ETX error
No ETX code is found.

11H:

Character error
A character not used in the received data is found.  (other than 0 to F)  Check the 
character and send the command again.

12H:

Command error
An invalid command is given.

13H:

Memory setting error
The address or device number is invalid.

STX

V7 Port 

number

Command

Read

Words

Memory

Model

Memory

Type

Address

System reserved

ETX

SUM

01H

20H

0AH

00H

00H

03E8H

0 0 0 0 0 0 0 0 0 0H

B9H

02H

30H31H

32H30H

30H41H

30H30H

30H30H

30H 33H 45H 38H

30H 30H 30H 30H 30H 30H 30H 30H 30H 30H

03H

42H39H

02H + 30H + 31H + 32H + 30H + 30H + 41H + 30H + 30H + 30H + 30H + 30H + 33H + 45H + 38H

+ 30H + 30H + 30H + 30H + 30H + 30H + 30H + 30H + 30H + 30H + 03H = 

4

B9

H