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A.3 VLYNQ 2.0 Packet Format
bytecnt
10bits
cmd2
10bits
cmd1
10bits
address
<4*10bits
data
N*10bits
eop
10bits
pkttype adrmask
VLYNQ 2.0 Packet Format
The VLYNQ 2.0 packet format is shown in Figure A-1 and described in Table A-3 , where 0<N<65.
Multi-byte fields are transferred least-significant byte first.
Figure A-1. Packet Format (10-bit Symbol Representation)
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
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/.
SPRUF89 – October 2007 VLYNQ Protocol Specifications 47
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