Public Version
MMC/SD/SDIO Integration
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All these clocks are generated and controlled by the power, reset, and clock manager (PRCM) module
(see
, Power, Reset, and Clock Management for more information).
24.3.1.1.2 Power Management
The MMC/SD/SDIO host controller can enter into different modes and save power:
•
Normal mode
•
Idle mode
The two modes are mutually exclusive (the module can be in normal mode or in idle mode). The
MMC/SD/SDIO host controller is compliant with the PRCM module handshake protocol.
Normal Mode
The autogating of interface and functional clocks occurs when the following conditions are met:
•
The MMCi.
[0] AUTOIDLE bit is set to 1 (I = 1 for MMC/SD/SDIO1, 2 for
MMC/SD/SDIO2 and 3 for MMC/SD/SDIO3 instances).
•
There is no transaction on the MMC interface.
The autogating of interface and functional clocks stops when the following conditions are met:
•
A register access occurs through the L4 interconnect.
•
A wake-up event occurs (an interrupt from a SDIO card).
•
A transaction on the MMC/SD/SIO interface starts.
Then the MMC/SD/SDIO host controller enters in low-power state (MMCi_ICLK clock autogated) even if
MMCi.
[0] AUTOIDLE is set to 0.
The functional clock is internally switched off and only interconnect read and write accesses are allowed.
Idle Mode
The MMCi_ICLK and MMCi_FCLK clocks provided to MMC/SD/SDIO are switched off upon a PRCM
module request. They are switched back upon module request.
The MMC/SD/SDIO host controller complies with the PRCM module handshaking protocol:
•
Idle request from the system power manager
•
Idle acknowledgment from the MMC/SD/SDIO host controller
•
Wake-up request from the MMC/SD/SDIO host controller
The idle acknowledgment varies according to the MMCi.
[4:3] SIDLEMODE bit field:
•
0x0: Force-idle mode. The MMC/SD/SDIO host controller acknowledges the system power manager
request unconditionally.
•
0x1: No-idle mode. The MMC/SD/SDIO host controller ignores the system power manager request and
behaves normally as if the request was not asserted.
•
0x2: Smart-idle mode. The MMC/SD/SDIO host controller acknowledges the system power manager
request according to its internal state.
During the smart-idle mode period, the MMC/SD/SDIO host controller acknowledges that the MMCi_ICLK
and MMCi_FCLK clocks may be switched off whatever the value set in the
MMCi.
[9:8] CLOCKACTIVITY field.
Transition From Normal Mode to Smart-Idle Mode
Smart-idle mode is enabled when the MMCi.
[4:3] SIDLEMODE bit field is set to
0x2.
The MMC/SD/SDIOi host controller goes into idle mode when the PRCM issues an idle request, according
to its internal activity.
During normal to idle mode transition, any access to the registers of the MMC/SD/SDIOi host controller
generates an error as long as the MMCi_ICLK clock is alive. The PRCM.CM_IDLEST1_CORE[25]
ST_MMC2 and (respectively the PRCM.CM_IDLEST1_CORE[24] ST_MMC1 bit) is set to 0x0 when the
MMC/SD/SDIO2 module (respectively the MMC/SD/SDIO1 module) can be accessed.
3376
MMC/SD/SDIO Card Interface
SWPU177N – December 2009 – Revised November 2010
Copyright © 2009–2010, Texas Instruments Incorporated
Содержание OMAP36 Series
Страница 174: ...174 List of Tables SWPU177N December 2009 Revised November 2010 Copyright 2009 2010 Texas Instruments Incorporated ...
Страница 692: ...692 MPU Subsystem SWPU177N December 2009 Revised November 2010 Copyright 2009 2010 Texas Instruments Incorporated ...
Страница 1084: ...1084 IVA2 2 Subsystem SWPU177N December 2009 Revised November 2010 Copyright 2009 2010 Texas Instruments Incorporated ...
Страница 1990: ...1990 2D 3D Graphics Accelerator SWPU177N December 2009 Revised November 2010 Copyright 2009 2010 Texas Instruments Incorporated ...
Страница 2334: ...2334 Memory Subsystem SWPU177N December 2009 Revised November 2010 Copyright 2009 2010 Texas Instruments Incorporated ...
Страница 2700: ...2700 Memory Management Units SWPU177N December 2009 Revised November 2010 Copyright 2009 2010 Texas Instruments Incorporated ...
Страница 2868: ...2868 HDQ 1 Wire SWPU177N December 2009 Revised November 2010 Copyright 2009 2010 Texas Instruments Incorporated ...
Страница 2974: ...2974 UART IrDA CIR SWPU177N December 2009 Revised November 2010 Copyright 2009 2010 Texas Instruments Incorporated ...
Страница 3054: ...3054 Multichannel SPI SWPU177N December 2009 Revised November 2010 Copyright 2009 2010 Texas Instruments Incorporated ...
Страница 3462: ...3462 MMC SD SDIO Card Interface SWPU177N December 2009 Revised November 2010 Copyright 2009 2010 Texas Instruments Incorporated ...
Страница 3508: ...3508 General Purpose Interface SWPU177N December 2009 Revised November 2010 Copyright 2009 2010 Texas Instruments Incorporated ...
Страница 3584: ...3584 Initialization SWPU177N December 2009 Revised November 2010 Copyright 2009 2010 Texas Instruments Incorporated ...
Страница 3648: ...3648 Debug and Emulation SWPU177N December 2009 Revised November 2010 Copyright 2009 2010 Texas Instruments Incorporated ...