CS47L85 datasheet(194/370 Pages) CIRRUS

194 / 370 page

CS47L85

194

Rev 4.3

VALUE MANAGEMENT (INCLUDING REGISTER ACCESS)

A memory map of Value Elements is defined for each Device. This is arranged in 3 x 1kByte blocks, comprising Core Value

elements, Device Class-specific Value elements, and User Value elements respectively, as described in the MIPI

specification. These elements are typically parameters used to configure Device behaviour.

The User Value elements of the Interface Device are used on CS47L85 to support Read/Write access to the Register Map.

Details

of how to access specific registers are described in the “SLIMbus Interface Control” section.

Note that, with the exception of the User Value elements of the Interface Device, the contents of the User Value portion for

each CS47L85 SLIMbus Device are reserved.

Read/Write access is implemented using the messages described below. Specific elements within the Value Map are

identified using the Element Code (EC) parameter. In the case of Read access, a unique Transaction ID (TID) is assigned

to each message relating to a particular read/write request.

The REQUEST_VALUE (TID, EC) message is used to instruct a device to respond with the indicated information. The

payload of this message contains the Transaction ID (TID) and the Element Code (EC).

The REPLY_VALUE (TID, VS) message is used to provide readback of a requested parameter. The payload of this message

contains the Transaction ID (TID) and the Value Slice (VS). The Value Slice byte(s) contain the value of the requested

parameter.

The CHANGE_VALUE (EC, VU) message is used to write data to a specified element in the Value Map. The payload of

this message contains the Element Code (EC) and the Value Update (VU). The Value Update byte(s) contain the new value

of the applicable parameter.

FRAME & CLOCKING MANAGEMENT

This section describes the SLIMbus messages associated with changing the Frame or Clocking configuration. One or more

configuration messages may be issued as part of a Reconfiguration Sequence; all of the updated parameters become active

at once, when the Reconfiguration boundary is reached.

The BEGIN_RECONFIGURATION message is issued to define a Reconfiguration Boundary point: subsequent NEXT_*

messages will become active at the first valid Superframe boundary following receipt of the RECONFIGURE_NOW message.

(A valid boundary must be at least two Slots after the end of the RECONFIGURE_NOW message.) Both of these messages

have no payload content.

The NEXT_ACTIVE_FRAMER (LAIF, NCo, NCi) message is used to select a new device as the active Framer. The payload

of this message includes the Logical Address, Incoming Framer (LAIF). Two other fields (NCo, NCi) define the number of

clock cycles for which the CLK line shall be inactive during the handover.

The NEXT_SUBFRAME_MODE (SM) and NEXT_CLOCK_GEAR (CG) messages are used to re-configure the SLIMbus

clocking or framing definition. The payload of each is the respective Subframe Mode (SM) or Clock Gear (CG) respectively.

The NEXT_PAUSE_CLOCK (RT) message instructs the active Framer to pause the bus. The payload of the message

contains the Restart Time (RT), which indicates whether the interruption is to be of a specified time and/or phase duration.

The NEXT_RESET_BUS message instructs all components on the bus to be reset. In this case, all Devices on the bus are

reset and are disconnected from the bus. Subsequent re-connection to the bus follows the same process as when the bus

is first initialised.

The NEXT_SHUTDOWN_BUS message instructs all devices that the bus is to be shut down.

DATA CHANNEL CONFIGURATION

This section describes the procedure for configuring a SLIMbus Data Channel. Note that the Manager Device is responsible

for allocating the available bandwidth as required for each Data Channel.

The CONNECT_SOURCE (PN, CN) and CONNECT_SINK (PN, CN) messages are issued to the respective devices,

defining the Port(s) between which a Data Channel is to be established. Note that multiple destinations (sinks) can be

configured for a channel, if required. The payload of each message contains the Port Number (PN) and the Channel Number

(CN) parameters.

The BEGIN_RECONFIGURATION message is issued to define a Reconfiguration Boundary point: subsequent NEXT_*

messages will become active at the first valid Superframe boundary following receipt of the RECONFIGURE_NOW message.

(A valid boundary must be at least two Slots after the end of the RECONFIGURE_NOW message.)

The NEXT_DEFINE_CHANNEL (CN, TP, SD, SL) message informs the associated devices of the structure of the Data

Channel. The payload of this message contains the Channel Number (CN), Transport Protocol (TP), Segment Distribution

(SD), and the Segment Length (SL) parameters for the Data Channel.

The NEXT_DEFINE_CONTENT (CN, FL, PR, AF, DT, CL, DL), or CHANGE_CONTENT (CN, FL, PR, AF, DT, CL, DL)

CS47L85 Datasheet(PDF) 194 Page - Cirrus Logic

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