--- /dev/null
+This file specifies the format of USB packets used for in-band data
+transmission and signaling on the USRP. All packets are 512-byte long,
+and are transfered using USB "bulk" transfers.
+
+IN packets are sent towards the host.
+OUT packets are sent away from the host.
+
+The layout is 32-bits wide. All data is transmitted in little-endian
+format across the USB.
+
+
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ |O|U|D|S|E| RSSI | Chan | mbz | Tag | Payload Len |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ | Timestamp |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ | |
+ + +
+ | Payload |
+ . .
+ . .
+ . .
+ | |
+ + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ | ... | .
+ +-+-+-+-+-+-+-+ .
+ . .
+ . Padding .
+ . .
+ | |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+
+ mbz Must be Zero: these bits must be zero in both IN and OUT packets.
+
+ O Overrun Flag: set in an IN packet if an overrun condition was
+ detected. Must be zero in OUT packets. Overrun occurs when
+ the FPGA has data to transmit to the host and there is no
+ buffer space available. This generally indicates a problem on
+ the host. Either it is not keeping up, or it has configured
+ the FPGA to transmit data at a higher rate than the transport
+ (USB) can support.
+
+ U Underrun Flag: set in an IN packet if an underrun condition
+ was detected. Must be zero in OUT packets. Underrun occurs
+ when the FPGA runs out of samples, and it's not between
+ bursts. See the "End of Burst flag" below.
+
+ D Dropped Packet Flag: Set in an IN packet if the FPGA
+ discarded an OUT packet because its timestamp had already
+ passed.
+
+ S Start of Burst Flag: Set in an OUT packet if the data is the
+ first segment of what is logically a continuous burst of data.
+ Must be zero in IN packets.
+
+ E End of Burst Flag: Set in an OUT packet if the data is the
+ last segment of what is logically a continuous burst of data.
+ Must be zero in IN packets. Underruns are not reported
+ when the FPGA runs out of samples between bursts.
+
+
+ RSSI 6-bit Received Strength Signal Indicator: Must be zero in OUT
+ packets. In IN packets, indicates RSSI as reported by front end.
+ FIXME The format and interpretation are to be determined.
+
+ Chan 5-bit logical channel number. Channel number 0x1f is reserved
+ for control information. See "Control Channel" below. Other
+ channels are "data channels." Each data channel is logically
+ independent of the others. A data channel payload field
+ contains a sequence of homogeneous samples. The format of the
+ samples is determined by the configuration associated with the
+ given channel. It is often the case that the payload field
+ contains 32-bit complex samples, each containing 16-bit real
+ and imaginary components.
+
+ Tag 4-bit tag for matching IN packets with OUT packets.
+ [FIXME, write more...]
+
+ Payload Len: 9-bit field that specifies the length of the payload
+ field in bytes. Must be in the range 0 to 504 inclusive.
+
+ Timestamp: 32-bit timestamp.
+ On IN packets, the timestamp indicates the time at which the
+ first sample of the packet was produced by the A/D converter(s)
+ for that channel. On OUT packets, the timestamp specifies the
+ time at which the first sample in the packet should go out the
+ D/A converter(s) for that channel. If a packet reaches the
+ head of the transmit queue, and the current time is later than
+ the timestamp, an error is assumed to have occurred and the
+ packet is discarded. As a special case, the timestamp
+ 0xffffffff is interpreted as "Now".
+
+ The time base is a free running 32-bit counter that is
+ incremented by the A/D sample-clock.
+
+ Payload: Variable length field. Length is specified by the
+ Payload Len field.
+
+ Padding: This field is 504 - Payload Len bytes long, and its content
+ is unspecified. This field pads the packet out to a constant
+ 512 bytes.
+
+
+
+"Data Channel" payload format:
+-------------------------------
+
+If Chan != 0x1f, the packet is a "data packet" and the payload is a
+sequence of homogeneous samples. The format of the samples is
+determined by the configuration associated with the given channel.
+It is often the case that the payload field contains 32-bit complex
+samples, each containing 16-bit real and imaginary components.
+
+
+"Control Channel" payload format:
+---------------------------------
+
+If Chan == 0x1f, the packet is a "control packet". The control channel
+payload consists of a sequence of 0 or more sub-packets.
+
+Each sub-packet starts on a 32-bit boundary, and consists of an 8-bit
+Opcode field, an 8-bit Length field, Length bytes of arguments, and 0,
+1, 2 or 3 bytes of padding to align the tail of the sub-packet to
+a 32-bit boundary.
+
+Control channel packets shall be processed at the head of the queue,
+and shall observe the timestamp semantics described above.
+
+
+General sub-packet format:
+--------------------------
+
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-//-+-+-+-+-+-+-+-+
+ | Opcode | Length | <length bytes> ... |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-//-+-+-+-+-+-+-+-+
+
+
+Specific sub-packet formats:
+----------------------------
+
+ RID: 6-bit Request-ID. Copied from request sub-packet into corresponding
+ reply sub-packet. RID allows the host to match requests and replies.
+
+ Reg Number: 10-bit Register Number.
+
+
+
+Ping Fixed Length:
+
+ Opcode: OP_PING_FIXED
+
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ | Opcode | 2 | RID | Ping Value |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+
+Ping Fixed Length Reply:
+
+ Opcode: OP_PING_FIXED_REPLY
+
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ | Opcode | 2 | RID | Ping Value |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+
+Write Register:
+
+ Opcode: OP_WRITE_REG
+
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ | Opcode | 6 | mbz | Reg Number |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ | Register Value |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+
+Write Register Masked:
+
+ Opcode: OP_WRITE_REG_MASKED
+
+ REG[Num] = (REG[Num] & ~Mask) | (Value & Mask)
+
+ That is, only the register bits that correspond to 1's in the
+ mask are written with the new value.
+
+
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ | Opcode | 10 | mbz | Reg Number |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ | Register Value |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ | Mask Value |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+
+Read Register:
+
+ Opcode: OP_READ_REG
+
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ | Opcode | 2 | RID | Reg Number |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+
+Read Register Reply:
+
+ Opcode: OP_READ_REG_REPLY
+
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ | Opcode | 6 | RID | Reg Number |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ | Register Value |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+
+I2C Write:
+
+ Opcode: OP_I2C_WRITE
+ I2C Addr: 7-bit I2C address
+ Data: The bytes to write to the I2C bus
+ Length: Length of Data + 2
+
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ | Opcode | Length | mbz | I2C Addr |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ | Data ... .
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+
+I2C Read:
+
+ Opcode: OP_I2C_READ
+ I2C Addr: 7-bit I2C address
+ Nbytes: Number of bytes to read from I2C bus
+
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ | Opcode | 3 | RID | mbz | I2C Addr |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ | Nbytes | unspecified padding |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+
+I2C Read Reply:
+
+ Opcode: OP_I2C_READ_REPLY
+ I2C Addr: 7-bit I2C address
+ Data: Length - 2 bytes of data read from I2C bus.
+
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ | Opcode | Length | RID | mbz | I2C Addr |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ | Data ... .
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+
+SPI Write:
+
+ Opcode: OP_SPI_WRITE
+ Enables: Which SPI enables to assert (mask)
+ Format: Specifies format of SPI data and Opt Header Bytes
+ Opt Header Bytes: 2-byte field containing optional Tx bytes; see Format
+ Data: The bytes to write to the SPI bus
+ Length: Length of Data + 6
+
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ | Opcode | Length | mbz |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ | Enables | Format | Opt Header Bytes |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ | Data ... .
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+
+SPI Read:
+
+ Opcode: OP_SPI_READ
+ Enables: Which SPI enables to assert (mask)
+ Format: Specifies format of SPI data and Opt Header Bytes
+ Opt Header Bytes: 2-byte field containing optional Tx bytes; see Format
+ Nbytes: Number of bytes to read from SPI bus.
+
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ | Opcode | 7 | RID | mbz |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ | Enables | Format | Opt Header Bytes |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ | Nbytes | unspecified padding |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+
+SPI Read Reply:
+
+ Opcode: OP_SPI_READ_REPLY
+ Data: Length - 2 bytes of data read from SPI bus.
+
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ | Opcode | Length | RID | mbz |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ | Data ... .
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+
+Delay:
+
+ Opcode: OP_DELAY
+ Ticks: 16-bit unsigned delay count
+
+ Delay Ticks clock ticks before executing next operation.
+
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ | Opcode | 2 | Ticks |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
projects / debian / gnuradio / blobdiff