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F_Star
Address
0x68
0x99
0x99
0x99
0x99
0x99
F_Star
0x68
C_cod
0x23
Length
len
0
1
2
3
4
5
7
8
9
0x99
6
Header
Data
CS
0x16
0..9
10..len+9
len+10 len+11
RSPH
RSPL
10
11
Respond Data
12..len+9
Respond is fitted into Data field as shown above
RSPH = CMDH, RSPL = CMDL | 0x80
F_Start
Address
0x68
0x99
0x99
0x99
0x99
0x99
F_Start
0x68
C_cod
e
0x23
Length
len
0
1
2
3
4
5
7
8
9
0x99
6
Header
Data
CS
0x16
0..9
10..len+9
len+10
len+11
CMDH
CMDL
10
11
Parameter
12..len+9
Communication Protocol
4.2.1.1
Command and Respond Frame
and
show the structure of the command and respond frame in polling mode. The
command and respond frame has the same structure in the header and the frame end, the difference is in
the data field. The first 2 bytes in the data field of a command is CMDH and CMDL which defines the
command and the parameters that follows. After receiving a valid command frame from the host, the EVM
responds to the host with a respond frame with the RSPH = CMDH and RSPL = CMDL | 0x80 (CMDL
cannot use value larger than 0x7F). The respond data is defined by the command received.
See
for the definition of commands and the corresponding responses.
Figure 4-2. Polling Mode Command Frame Format
Figure 4-3. Polling Mode Respond Frame Format
NOTE:
If writing a custom protocol, make sure that the data buffer is sufficient to hold the data from
the host.
24
Serial Communication Commands
SLAU587 – August 2014
Copyright © 2014, Texas Instruments Incorporated