Tiny Addressable Serial Converter
ICP DAS CO., LTD.
User Manual, Ver. 1.3, Apr. 2018, Page: 55
5.1.13 $AAU
Description:
Most RS-232 devices are passive and obey the rules of the request-reply protocol. If they
do not receive any commands, they will not send any messages out. However, more and
more active devices are developed to send out message automatically. So, ICPDAS tM-
752N controllers are designed with a 1-KB queue buffer on each RS-232 port to store
these active messages until the Host PC has time to read it. The feature allows the Host
PC linking with hundreds of RS-232 devices without any loss of data in short period.
Buffer operation rules:
Rule 1:
The buffer is enabled after being powered-on.
Rule 2:
The (delimiter) AA command disables the buffer operation for that port.
Rule 3:
After disabling the buffer, the controller will wait for X seconds (=Response
timeout,) for a response from the RS-232 device. The response will then be transferred to
COM1. If no message is received, the buffer will be re-enabled.
Syntax:
$AAU
[chk](CrLf)
Reads data from the RS-232 COM port buffer
[Request]
Byte 1
Byte 2-3
Byte 4
Byte 5-6
Byte 7-8
Note
$
AA
U
[chk]
(CrLf)
Read
$
AA
[chk]
(CrLf)
Delimiter character
2-character port address in Hex format. The valid range is from 00~FF
2-character checksum. If the checksum is disabled
no [chk]
End Character
