PNI CommBoard - Manual (Page 12)

PNI Sensor Corporation DOC#1018122 r02
PNI CommBoard User Manual Page 10
Table 5-2 defines the characters used in the syntax description. Note that when {NIML} or
(NIML) is used to define the word length, only N, I, M, or L should be present, not all four.
If the word length is optional and no word length is defined in the sentence, then the prior
specified word length will be used. Similarly, if the delimiter is optional and no delimiter is
provided, then the prior specified delimiter will be used on return data. This holds when
switching from a Read to a Write command, and vice-versa.
Table 5-2: SPI Syntax Character Definitions
Character Definition
( ) Required parameter inside parentheses
{ }
Optional parameter inside brackets
#
Number (data). Can include minus (-).
S, s
Treat incoming word as a signed value
N, n
Int8 value follows or is requested
I, i
Int16 value follows or is requested
M, m
Int24 value follows or is requested
L, l
Int32 value follows or is requested
W or w
– SPI Write
This character indicates a Write command. The data word is sent once a delimiter or
another command character is received from the host. The syntax is:
W{NIML}#(delimiter){{NIML}#(delimiter)..}{}
The data is #, and the data‟s word length is defined by either N, I, M, or L, as set out
in Table 5-2. If the optional carriage return is sent, it first serves as a delimiter to
complete a write value and next it serves to terminate this command such that the
character „W‟ or „w‟ has to be reissued to send additional data. Note that is not
stored as the last used delimiter (see Delimiter section for details).
Multiple words of varying word lengths can be sent in one sentence. The operands
„N‟, „I‟, „M‟ or „L‟ define the word length of the subsequent data being sent. These
can be upper or lower case. This operand does not need to be repeated if the word
length does not change.
Example: dWN123,456,i789
“d” sets the CommBoard to decimal mode. “W” defines this action as a Write
command. “N” defines the word length as 8-bits. “123” is the first set of data, in
decimal format. The delimiter is “,”. The next set of data, “456”, gets reduced to
“200” because 456 overflows the 8-bit word (255 max) and “200” is what remains
in the LSB. “i” changes the word length to 16-bits. “789” gets converted into “3”