30.9.1.3 Command Bytes
The MediaLB Command field is eight-bits wide and all odd values are reserved; therefore, the LSB of Command is always zero.
Transmitting MediaLB Devices (including the Controller) place Command on the MLBS line to indicate the type of data being transmitted on the MLBD line.
Two types of MediaLB commands are defined: Normal and System. Normal commands are those sent by the transmitting MediaLB Device (or Controller) in non-System Channels. System commands are those sent by the MediaLB Controller in the System Channel.
| Value (see Note) | Command | Description |
|---|---|---|
| Normal Commands (TX Device sends in non-system channels): | ||
| 00h | NoData | No data to send out in this physical channel. |
| 02h...0Eh | rsvd | Reserved |
| 10h | SyncData | Tx Device sends out SyncData command to indicate synchronous stream data. |
| 12h...1Eh | rsvd | Reserved |
| 20h | AsyncStart | Asynchronous logical channel. Start of a packet. |
| 22h | AsyncContinue | Asynchronous logical channel. Middle of a packet. |
| 24h | AsyncEnd | Asynchronous logical channel. End of a packet. |
| 26h | AsyncBreak | Asynchronous logical channel. Indicates a packet stop. No valid data present on the MLBD line. |
| 28h...2Eh | rsvd | Reserved |
| 30h | ControlStart | Control logical channel. Start of a message. |
| 32h | ControlContinue | Control logical channel. Middle of a message. |
| 34h | ControlEnd | Control logical channel. End of a message. |
| 36h | ControlBreak | Control logical channel. Indicates a message stop. No valid data present on the MLBD line. |
| 38h...3Eh | rsvd | Reserved |
| 40h | IsoNoData | Isochronous logical channel, no data valid. |
| 42h | Iso1Byte | Isochronous logical channel, one data byte valid. First byte (MSB) transmitted/received is valid. Last three bytes in physical channel are empty. |
| 44h | Iso2Bytes | Isochronous logical channel, first two data bytes valid. First byte transmitted/received is the MSB. Last two bytes in physical channel are empty. |
| 46h | Iso3Bytes | Isochronous logical channel, first three data bytes valid. First byte transmitted/received is the MSB. Last byte in physical channel is empty. |
| 48h | Iso4Bytes | Isochronous logical channel, all four data bytes valid. First byte transmitted/received is the MSB. |
| 4Ah...4Eh | rsvd | Reserved |
| 50h | IsoSync1Byte | Isochronous logical channel, one data byte valid and start of a block. First byte transmitted/received is valid. Last three bytes in physical channel are empty. |
| 52h | IsoSync2Bytes | Isochronous logical channel, two data bytes valid and start of a block. First byte transmitted/received is the MSB. Last two bytes in the physical channel are empty. |
| 54h | IsoSync3Bytes | Isochronous logical channel, three data bytes valid and start of a block. First byte transmitted/received is the MSB. Last byte in physical channel is empty. |
| 56h | IsoSync4Bytes | Isochronous logical channel, all four data bytes valid and start of a block. First byte transmitted/received is the MSB. |
| 58h...DEh | rsvd | Reserved |
| System Commands (Controller sends in System Channel): | ||
| 00h | NoData | The Controller has no System command to send out. |
| E0h | MOSTLock | The Controller issues a MOST Network lock command in the System Channel to notify Devices that the MOST Network is in lock. |
| E2h | MOSTUnlock | The Controller issues a MOST Network unlock command in the System Channel to notify Devices that the MOST Network is unlocked. |
| E4h | MLBScan | The Controller issues an MediaLB scan command in the System Channel and uses the MLBD line to indicate the DeviceAddress which is currently being scanned. All Devices supporting MLBScan must compare the received DeviceAddress against their internal DeviceAddress, and if a match occurs, a Device responds in the following System Channel with one of the System responses as specified in MediaLB RxStatus Responses. |
| E6h | MLBSubCmd | The Controller outputs a sub-command in the System Channel. The sub- command is part of the data on the MLBD line. |
| E8h...FCh | rsvd | Reserved |
| FEh | MLBReset | The Controller outputs a MediaLB reset on the System Channel MLBS line. If the first two-bytes are zero on the MLBD line, then the system reset is a broadcast system reset and every Device should reset its MediaLB interface. Otherwise, the MLBD line contains the DeviceAddress of the Device being asked to reset its own MediaLB interface. |
For synchronous logical channels, the NoData command indicates that the Tx Device assigned to that ChannelAddress has not setup the channel yet. For asynchronous and control logical channels, NoData is used during packet data transfer when there is no data available to transmit.