Description – Texas Instruments VLYNQ Port User Manual
Page 42
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VLYNQ 2.0 Packet Format
Table A-3. Packet Format (10-bit Symbol Representation) Description
Field
Value Description
PKTTYPE[3:0]
This field indicates the packet type.
0000
Reserved
0001
Write with address increment.
0010
Reserved
0011
Write 32-bit word with address increment.
0100
Reserved
0101
Configuration write with address increment.
0110
Reserved for extended command indicator (cmd2).
0111
Interrupt
1000
Reserved
1001
Read with address increment.
1010
Reserved
1011
Read 32-bit word with address increment.
1100
Reserved
1101
Configuration read with address increment.
1110
Reserved for VLYNQ version 2.0 and later.
1111
Read response for all VLYNQ versions.
ADRMASK[3:0]
Indicates which byte of the address is included in the packet. Only address bytes that have changed
since the previous address will be included. Each bit corresponds to one byte of address.
BYTECNT[7:0]
Byte count. This field indicates the total number of bytes in the packet. This field is only included for
write, read, and configuration packet types. All other packet types have fixed lengths and do not
require this field.
ADDRESS[7:0]
Address byte 0. This byte is included only if ADRMASK[0] is set to 1. If ADRMASK[0] is cleared to 0,
assume this byte is equal to bits 7:0 of the previous address. Read response packets do not include
this field.
ADDRESS[15:8]
Address byte 1. This byte is included only if ADRMASK[1] is set to 1. If ADRMASK[1] is cleared to 0,
assume this byte is equal to bits 15:8 of the previous address. Read response packets do not include
this field.
ADDRESS[23:16]
Address byte 2. This byte is only included if ADRMASK[2] is set to 1. If ADRMASK[2] is cleared to 0,
this assume this byte is equal to bits 23:16 of the previous address. Read response packets do not
include this field.
ADDRESS[31:24]
Address byte 3. This byte is only included if ADRMASK[3] is set to 1. If ADRMASK[3] is cleared to 0,
assume this byte is equal to bits 31:24 of the previous address. Read response packets do not
include this field.
DATA
Data payload. The maximum data payload size is limited to sixteen 32-bit words to allow it to fit in the
RX FIFO.
EOP
End of packet indicator, /T/.
The CMD2 bit is only included in the packet, if the packet type indicates extended command
(PKTTYPE = 0110).
Use configuration packet types to remotely access VLYNQ module registers. The configuration packet
types do not depend on control register bit settings.
VLYNQ Protocol Specifications
42
SPRUE36A – September 2007