Microchip Technology SA5 Series, User Manual

Page: 32 / 63

MAC-SA5X User’s Guide
DS50002938A-page 32

2019 Microchip Technology Inc.
For example, the response to the invalid command
{type7}
would be:
[!1]<CR><LF>
4.2.2 Response Checksum
The checksum of a response is calculated as a running XOR of all the characters
between the opening ‘[‘ and the ‘|’ checksum delimiter. See the double underlined por-
tion of the response below:
[#XX=value|CC]<CR><LF>
For example, the checksum-response to the
{device?|27}
command would be:
[=sa5x|62]<CR><LF>
4.3 ANNOUNCEMENT STRUCTURE
The structure of a C3 announcement follows:
[>message|CC]<CR><LF>
Where:
TABLE 4-5: ANNOUNCEMENT STRUCTURE
Field Description Usage
[
Indicates the start of an announcement Always
>
Identifies this as an announcement, versus a response or
error.
Always
message
The announcement message. It may be alphanumeric or a
quoted string.
Always
|CC
The 8-bit checksum of the announcement message.
(CC = two hex digits) Currently unused
feature
]
Indicates the end of an announcement Always
<CR>
A carriage return character. Always
<LF>
A linefeed/newline character. Always
Currently, announcements only occur immediately after applying power to the unit (or
resetting the microprocessor):
[>Loading...]<CR><LF>
[>Microchip SA5X]<CR><LF>
4.4 PARAMETERS
The state of the device is exposed as a set of parameters: named values with semantic
attributes. Certain parameters are readable/writable to allow the device to be controlled
and configured, while other read-only parameters present useful status information.
Parameters are uniquely identified by either a numeric id (e.g.
769
) or a name (e.g.
PpsSource
). The device provides a set of commands to indicate which parameters
are available to the user and to describe each one, including name string, real world
units, whether it’s writable, etc.
320 Erase failed An error occurred while erasing flash memory.
321 Write failed An error occurred while writing to flash memory.
TABLE 4-4: ERROR RESPONSES
Error Number Error Message Cause(s)