ElmoMC CANopen DS 301 Implementation Guide - Manual (Page 22)

4.1 Initiate SDO Download Protocol
This protocol is used to implement the Initiate SDO Download service.
Client to server:
0
1 4 8
7…5 4 3…2 1 0
css = 1 x n e s m d (data)
Server to client:
0
1 4 8
7…5 4…0
scs = 3 x m reserved
where:
css
Client command specifier
1: Initiate download request
scs Server command specifier
3: Initiate download response
n Number of bytes in d that do not contain data. Only valid if
e = 1 and s = 1; otherwise it is 0. Bytes [8-n, 7] do not contain data.
e Transfer type
0: Normal transfer
1: Expedited transfer
s Size indicator
0: Data set size is not indicated
1: Data set size is indicated
m Multiplexor. Represents index/sub-index of data to be transferred by
SDO.
d Data
e = 0, s = 0: d is reserved for future use.
e = 0, s = 1: d contains number of bytes to be downloaded.
Byte 4 contains LSB and byte 7 contains MSB.
e = 1, s = 1: d contains data of length 4-n to be downloaded. The encoding
depends on the type of data referenced by index and sub-index.
e = 1, s = 0: d contains an unspecified number of bytes to be downloaded.
x Not used; always 0.
reserved Reserved for future use; always 0.
CANopen DS 301 Implementation Guide Service Data Objects (SDOs)
MAN-CAN301IG (Ver. 2.1)
4-2