WM5102 datasheet(141/334 Pages) WOLFSON

141 / 334 page

Production Data

WM5102

PD, June 2014, Rev 4.2

141

In some applications, the allocated SLIMbus bandwidth must be greater than the data rate, to ensure

that samples are not dropped as a result of clock drift etc. The SLIMbus bandwidth should only be set

equal to the data rate if the data source is frequency-locked to the SLIMbus CLK (ie. the data source

is synchronised to the SLIMbus Framer device).

SLIMBUS CONTROL SEQUENCES

This section describes the messages and general protocol associated with most aspects of the

SLIMbus system.

Note that the SLIMbus specification permits some flexibility in Core Message support for different

components. See “SLIMbus Interface Control” for details of which message(s) are supported on each

of the SLIMbus devices that are present on the WM5102.

DEVICE MANAGEMENT & CONFIGURATION

This section describes the SLIMbus messages associated with configuring all devices on the SLIMbus

interface.

When the SLIMbus interface starts up, it is required that one (and only one) of the components

provides the Manager and Framer Device functions. Other devices can request connection to the bus

after they have gained synchronisation.

The REPORT_PRESENT (DC, DCV) message may be issued by devices attempting to connect to the

bus. The payload of this message contains the Device Class (DC) and Device Class Version (DCV)

parameters, describing the type of device that is attempting to connect. This message may be issued

autonomously

the

connecting

device,

else

response

REQUEST_SELF_ANNOUNCEMENT message from the Manager Device.

After positively acknowledging the REPORT_PRESENT message, the Manager Device will then issue

the ASSIGN_LOGICAL_ADDRESS (LA) message to allow the other device to connect to the bus.

The payload of this message contains the Logical Address (LA) parameter only; this is the unique

address by which the connected device will send and receive SLIMbus messages. The device is then

said to be ‘enumerated’.

Once a device has been successfully connected to the bus, the Logical Address (LA) parameter can

be changed at any time using the CHANGE_LOGICAL_ADDRESS (LA) message.

The RESET_DEVICE message commands an individual SLIMbus device to perform its reset

procedure. As part of the reset, all associated ports will be reset, and any associated Data Channels

will be cancelled. Note that, if the RESET_DEVICE command is issued to an Interface Device, it will

cause a Component Reset (ie. all Devices within the associated component are reset). Under a

Component Reset, every associated Device will release its Logical Address, and the Component will

become disconnected from the bus.

INFORMATION MANAGEMENT

A memory map of Information Elements is defined for each Device. This is arranged in 3 x 1kByte

blocks, comprising Core Information elements, Device Class-specific Information elements, and User

Information elements respectively, as described in the MIPI specification. Note that the contents of the

User Information portion for each WM5102 SLIMbus Device are reserved.

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

Information 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_INFORMATION (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 REQUEST_CLEAR_INFORMATION (TID, EC, CM) message is used to instruct a device to

respond with the indicated information, and also to clear all, or parts, of the same information slice.

The payload of this message contains the Transaction ID (TID), Element Code (EC), and Clear Mask

(CM)

. The Clear Mask field is used to select which element(s) are to be cleared as part of the

instruction.

WM5102 Datasheet(PDF) 141 Page - Wolfson Microelectronics plc

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