CocoTB Framework · Verification Infrastructure for RTL Testing GitHub · Documentation Index · MIT License

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wb4_packet.py

WB4Packet(Packet): one Wishbone transfer, request and termination together.

Field	Bits	Driven by	Meaning
we	1	master	0 read, 1 write
adr	addr_width	master	byte address
dat_w	data_width	master	write data (DAT_O at the master)
sel	data_width/8	master	byte select; default all ones
cti	3	master	burst hint: 0 CLASSIC, 1 CONST, 2 INCR, 7 EOB
bte	2	master	burst type: 0 LINEAR, 1 WRAP4, 2 WRAP8, 3 WRAP16
dat_r	data_width	slave	read data (DAT_I at the master)
status	2	slave	0 ACK, 1 ERR, 2 RTY

cti and bte are the registered-feedback burst hints of B4 chapter 4. They are advisory: nothing in the framework acts on one, and no block in the RTL library does either -- what a burst means belongs to the peripheral. Both put the non-burst case at zero, so a packet built for a bus with no hint wires compares equal to one sampled off that bus, and every testbench written before the hints existed still pairs its packets the same way.

Metadata outside the fields: count (ordinal at the component that built it), start_time (request presented), end_time (terminated); all three are skipped by ==. Properties: direction ('READ'/'WRITE'), status_name, cti_name, bte_name, and in_burst (the hint is not CLASSIC). formatted(compact=True) gives one line, naming the hints only when a transfer actually carries one:

WB WRITE adr=0x00001234 sel=0b1111 dat_w=0xDEADBEEF ACK
WB READ  adr=0x00001238 sel=0b1111 dat_r=0x0000002A EOB/WRAP8 ACK

WB4Packet.create_wb4_field_config(addr_width, data_width, sel_width) is the FieldConfig the BFMs use; pass your own to the constructor to add fields.