SLIMbus Introduction AP Tech

Introduction to SLIMbus?
Presenter: Xavier Lambrecht (LnK) Revision: 1.0 Date: 03rd January 2012
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What is SLIMbus? ? Inter IC bus
? Developed by the MIPI? Alliance (LML WG) ? Target = REPLACE I2S, I2C, SPI, UART
– Bit rate up to 28 Mbps – Audio (video) streaming, Device control, Data transport
? No backward pin compatibility with I2S, I2C, SPI, UART ? Low pin count (2 = Clock & Data) ? Multi-drop topology: All the components share the clock and the data lines Manli88@https://www.wendangku.net/doc/a37276840.html,

SLIMbus High Level Features
? Transport of (L-PCM) audio streams
– Support various sampling rates concurrently (8, 11.025, 16, 22.05, 32, 44.1, 48, 88.2, 96, 192… KHz) – Support Sample on Demand (SoD) mechanisms (cf. AC’97)
? Transport of asynchronous data (UART like
emulation)
? Possible use of the SLIMbus clock for audio applications
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SLIMbus High Level Features
? Establish peer-2-peer links or multicast data links (no concentrator involved in data streaming) ? Time Division Multiplex Access (TDMA) ? Clock synchronous transmission ? Bandwidth partitioning between Control and Data ? Message based control (CRC protected)
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SLIMbus Benefits
? ? ? ? ? ? ? Standardize more ISO layers than legacy interfaces Reduce the pin count Decouple analogue and digital functions in a system Foundation for distributed architecture Make platform design more future proof Dynamically reconfigurable (power and bandwidth) Standardized Message set for improved software reuse and increased interoperability ? Allow for unforeseen use cases
? Reduce time to market ? Reduce integral cost
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Platform Expandability
SLIMbus electrical backbone
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Powerful Data Connectivity
Stereo streams (L+R) ? 48 kHz / 16 bits = 728 kbps ? 48 kHz / 16 bits = 728 kbps Message Channel
SLIMbus electrical backbone
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Resource Sharing
SLIMbus electrical backbone
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Component changes
Legacy I/F digital speaker
MCLK BCLK LRCLK DATA I2S I/F EQUALIZATION FILTERS CLASS D AMPLIFIER
SDA SCL
I2C I/F
SLIMbus digital speaker
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The nightmare of the wires…
#1
Application Engine
#2
#3
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… and the dream of the layouters
#1
Application Engine
#2
#3
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SLIMbus Building Blocks
Generic Device Class Manager Device Class Framer Device Class Interface Device Class
S b C pe L u o on I s mn t M
Optional Optional Optional Mandatory
S b Di e L u e I s v M c S b Di e L u ec I M s v S b Di e L u ec I s v M D At A o DTpt A pr To DA o AA t TP r r
S b L u I s M Ma r ag ne
S b L u I s M Fm r e a r
S b L u I s M I tr c nf e ea
DA A T CC L K O Fm C n l G e h n r i g h n, u C n l an a e i d ae S rd e a C n l heM g h n a s e ae s D Ah n A Cn l T ae
Transport Protocols
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Framing Hierarchical View
Framing Channel Frame Superframe Frame Frame Frame Frame Frame Frame Frame
Frame
Subframe
Subframe
...
Subframe
Subframe
...
Subframe
Control
Data
Slots
0b1011
0b0010
0b1110
0b0100
Cells
C3 1
C2 0
C1 1
C0 1
C3 0
C2 0
C1 1
C0 0
C3 1
C2 1
C1 1
C0 0
C3 0
C2 1
C1 0
C0 0
CLK
Framing Channel Frame Sync Symbol Framing Information
Guide Channel Message Channel
Data Channels
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SLIMbus Framing Units
? ? ? ? 1 Slot = 4 bits (C3, C2, C1, C0) 1 Subframe = 6, 8, 24 or 32 Slots 1 Frame = 192 slots (768 bits) 1 Superframe = 8 Frames
– 1536 Slots – 6144 bits
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Typical Superframe Drawing
96 Slots = ? Frame S0 F
0
1 Subframe Time S96
S95
F
1
F
2
F
3
Time
F
4
F
5
F
6
F
7
Sx=[C3, C2, C1, C0], S0 transmitted first, S1535 transmitted last first, F7 transmitted Fx=[S0, S1,…, S191], F0 transmitted Manli88@https://www.wendangku.net/doc/a37276840.html,last
S1535
SLIMbus Framing Entities
DATA CHANNELS CONTROL SPACE (Message Channel) GUIDE CHANNEL
FRAMING CHANNEL
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DATA SPACE

SLIMbus Message Flow
? Some messages are unicast (to 1 device)
? REQUEST_VALUE ? REPLY_VALUE ? CHANGE_VALUE
Register access messages
? Some messages are Broadcast (to all devices)
? REQUEST_SELF_ANNOUNCEMENT
? Reconfiguration Sequences (to all devices)
? ? ? ? BEGIN_RECONFIGURATION NEXT_CLOCK_GEAR NEXT_xxx … RECONFIGURE_NOW
Bus Management Messages
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SLIMbus Message Flow
Device #2
LA=0x04 EA=0x025*********
Device #3
LA=0x05 EA=0x025*********
Device #1
LA=0x02 EA=01C100010200
Device #4
LA=0x0A EA=0x025*********
LA = Logical Address (8 bits) - Dynamically assigned by Manager - Used for most transactions
Manager
LA=0xFF EA=01C100010300
EA = Enumeration Address (48 bits) - Assigned at Silicon design time - Used at boot time to enumerate Manli88@https://www.wendangku.net/doc/a37276840.html,
LA and EA are unique device identifiers

SLIMbus Message Protocol
Message header: -Message Type -Remaining Length -Message Code -Destination Type -Primary Integrity (CRC) -Destination Address Message Parameters -Arguments of the message code Message Integrity -4 bits CRC
CRC ARBITRATION HEADER PAYLOAD CRC RESPONSE
To gain access to the Message Channel -Arbitration Type -Arbitration Priority -Source Address
Response from destination device -No Response -Negative Acknowledgment (NACK) -Positive Acknowledgment (PACK)
2 CRC fields of 4 bits to protect the message against errors
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