Protocol Micro-Reader To Pc - Texas Instruments 2000 Series Reference Manual

Protocol Micro-reader to PC

2.1.4 Data Field
The presence of the relevant data field depends on the setting of the bits in the Command Field.
If the relevant bit (for example: Command bit 3 "Power Burst I") is set to "1", then Data Field 1 is present
defining the Power Burst length. If the relevant bit in the Command Field is set to "0" the consequent Data
Field is omitted, this results in the following data field being moved forward (decremented) by one.
Data Field
1 Power Burst I
2 Power Pause Duration
3 Power Burst II
4/5 toffLow (LSByte/MSByte)
6/7 tonLow (LSByte/MSByte)
8/9 toffHigh (LSByte/MSByte)
10/11 tonHigh (LSByte/MSByte)
12 # of Data Fields that follow
13.. Data Fields
(1)
The number of Data Fields must not cause an infringement of the total number of bytes allowed within a protocol frame.
Transponder command protocols are described in detail in
2.1.5 BCC
The 'BCC' field is a one-byte value of the Longitudinal Redundancy Check calculation (Xor'ed bytes) for
the preceding message. The calculation is performed on the whole message excluding the Start-Mark.
2.2 Protocol Micro-reader to PC
See Section 5.2 for examples.
20 Communications Protocol
Use Range (dec)
1..255 ms
1..255 ms
1..255 ms
28..2044 ms
28..2044 ms
28..2044 ms
28..2044 ms
(1)
See
LSByte first
Example: 02 08 32
02
08
--------------------------------
XOR 0000 1010
32
--------------------------------
XOR 0011 1000 = 38 (hex)
Start Length Status
Byte Contents (hexadecimal value)
0 Start Mark (SOH, 01
1 Length
2 Status
3 Data Field (1) (LSByte)
.
.
.
N+2 Data Field (N) (MSByte)
N+3 BCC
If bit 3 of Command Field(1) is set
If bit 4 of Command Field(1) is set
If bit 5 of Command Field(1) is set
If bit 0 of Command Field(2) is set
If bit 0 of Command Field(2) is set
If bit 0 of Command Field(2) is set
If bit 0 of Command Field(2) is set
If bit 6 of Command Field(1) is set
Section 4.1.
0000 0010
0000 1000
0011 0010
Data BCC
)
hex
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SCBU027 – May 2000
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