# EMIF Module

The external memory interface (EMIF) API provides a set of functions to configure device’s EMIF module. The driver provides functions to initialize the module, configure external memory parameters, obtain status information and to manage interrupts. APIs for both asynchronous and synchronous modes are supported.

group `emif_api`

  Defines

  `EMIF_ACCPROT0_FETCHPROT` MEMCFG_EMIF1ACCPROT0_FETCHPROT_EMIF1

    This flag is used to specify whether CPU fetches are allowed/blocked for EMIF.

  `EMIF_ACCPROT0_CPUWRPROT` MEMCFG_EMIF1ACCPROT0_CPUWRPROT_EMIF1

    This flag is used to specify whether CPU writes are allowed/blocked for EMIF.

  `EMIF_ACCPROT0_DMAWRPROT` MEMCFG_EMIF1ACCPROT0_DMAWRPROT_EMIF1

    This flag is used to specify whether DMA writes are allowed/blocked for EMIF. It is valid only for EMIF1 instance.

  `EMIF_ACCPROT0_MASK_EMIF1` ((uint16_t)MEMCFG_EMIF1ACCPROT0_FETCHPROT_EMIF1

  |\

  (uint16_t)

  MEMCFG_EMIF1ACCPROT0_CPUWRPROT_EMIF1

  |\

  (uint16_t)

  MEMCFG_EMIF1ACCPROT0_DMAWRPROT_EMIF1)
  `EMIF_ACCPROT0_MASK_EMIF2` ((uint16_t)MEMCFG_EMIF2ACCPROT0_FETCHPROT_EMIF2

  |\

  (uint16_t)

  MEMCFG_EMIF2ACCPROT0_CPUWRPROT_EMIF2)
  `EMIF_ASYNC_CS_CR_MASK` ((uint32_t)EMIF_ASYNC_CS2_CR_R_HOLD_M

  | \

  (uint32_t)

  EMIF_ASYNC_CS2_CR_R_STROBE_M

  | \

  (uint32_t)

  EMIF_ASYNC_CS2_CR_R_SETUP_M

  | \

  (uint32_t)

  EMIF_ASYNC_CS2_CR_W_HOLD_M

  | \

  (uint32_t)

  EMIF_ASYNC_CS2_CR_W_STROBE_M

  | \

  (uint32_t)

  EMIF_ASYNC_CS2_CR_W_SETUP_M

  | \

  (uint32_t)

  EMIF_ASYNC_CS2_CR_TA_M)
  `EMIF_ASYNC_INT_MASK` ((uint16_t)EMIF_INT_MSK_SET_AT_MASK_SET

  | \

  (uint16_t)

  EMIF_INT_MSK_SET_LT_MASK_SET

  | \

  (uint16_t)

  EMIF_INT_MSK_SET_WR_MASK_SET_M)
  `EMIF_ASYNC_INT_AT` EMIF_INT_MSK_SET_AT_MASK_SET

    This flag is used to allow/block EMIF to generate Masked Asynchronous Timeout interrupt.

  `EMIF_ASYNC_INT_LT` EMIF_INT_MSK_SET_LT_MASK_SET

    This flag is used to allow/block EMIF to generate Masked Line Trap interrupt.

  `EMIF_ASYNC_INT_WR` EMIF_INT_MSK_SET_WR_MASK_SET_M

    This flag is used to allow/block EMIF to generate Masked Wait Rise interrupt.

  `EMIF_MSEL_KEY` 0x93A5CE70U
  `EMIF_SYNC_SDRAM_CR_MASK` ((uint32_t)EMIF_SDRAM_CR_PAGESIGE_M

  | \

  (uint32_t)

  EMIF_SDRAM_CR_IBANK_M

  | \

  (uint32_t)

  EMIF_SDRAM_CR_BIT_11_9_LOCK

  | \

  (uint32_t)

  EMIF_SDRAM_CR_CL_M

  | \

  (uint32_t)

  EMIF_SDRAM_CR_NM

  | \

  (uint32_t)

  EMIF_SDRAM_CR_SR)
  `EMIF_SYNC_SDRAM_TR_MASK` ((uint32_t)EMIF_SDRAM_TR_T_RRD_M

  | \

  (uint32_t)

  EMIF_SDRAM_TR_T_RC_M

  | \

  (uint32_t)

  EMIF_SDRAM_TR_T_RAS_M

  | \

  (uint32_t)

  EMIF_SDRAM_TR_T_WR_M

  | \

  (uint32_t)

  EMIF_SDRAM_TR_T_RCD_M

  | \

  (uint32_t)

  EMIF_SDRAM_TR_T_RP_M

  | \

  (uint32_t)

  EMIF_SDRAM_TR_T_RFC_M)

  Enums

  enum `EMIF_AsyncCSOffset`

    Values that can be passed to EMIF_setAsyncMode(), EMIF_setAsyncTimingParams(), EMIF_setAsyncDataBusWidth(), EMIF_enableAsyncExtendedWait() and EMIF_disableAsyncExtendedWait() as the offset parameter. Three chip selects are available in asynchronous memory interface so there are three configuration registers available for each EMIF instance. All the three chip select offsets are valid for EMIF1 while only EMIF_ASYNC_CS2_OFFSET is valid for EMIF2.

    Values:

    enumerator `EMIF_ASYNC_CS2_OFFSET` = 0x8U

      Async chip select 2 offset.

    enumerator `EMIF_ASYNC_CS3_OFFSET` = 0xAU

      Async chip select 3 offset.

    enumerator `EMIF_ASYNC_CS4_OFFSET` = 0xCU

      Async chip select 4 offset.

  enum `EMIF_AsyncDataWidth`

    Values that can be passed to EMIF_setAsyncDataBusWidth() as the width parameter.

    Values:

    enumerator `EMIF_ASYNC_DATA_WIDTH_8` = 0x0000U

      ASRAM/FLASH with 8 bit data bus.

    enumerator `EMIF_ASYNC_DATA_WIDTH_16` = 0x0001U

      ASRAM/FLASH with 16 bit data bus.

    enumerator `EMIF_ASYNC_DATA_WIDTH_32` = 0x0002U

      ASRAM/FLASH with 32 bit data bus.

  enum `EMIF_AsyncMode`

    Values that can be passed to EMIF_setAsyncMode() as the mode parameter.

    Values:

    enumerator `EMIF_ASYNC_STROBE_MODE` = 0x80000000U

      Enables ASRAM/FLASH strobe mode.

    enumerator `EMIF_ASYNC_NORMAL_MODE` = 0x00000000U

      Disables ASRAM/FLASH strobe mode.

  enum `EMIF_AsyncWaitPolarity`

    Values that can be passed to EMIF_setAsyncWaitPolarity() as the polarity parameter.

    Values:

    enumerator `EMIF_ASYNC_WAIT_POLARITY_LOW` = 0x00000000U

      EMxWAIT pin polarity is low.

    enumerator `EMIF_ASYNC_WAIT_POLARITY_HIGH` = 0x10000000U

      EMxWAIT pin polarity is high.

  enum `EMIF_SyncNarrowMode`

    Values that can be passed to EMIF_setSyncMemoryConfig() as the config parameter member.

    Values:

    enumerator `EMIF_SYNC_NARROW_MODE_TRUE` = 0x00004000U

      MemBusWidth=SystemBusWidth/2.

    enumerator `EMIF_SYNC_NARROW_MODE_FALSE` = 0x00000000U

      MemBusWidth=SystemBusWidth.

  enum `EMIF_SyncBank`

    Values that can be passed to EMIF_setSyncMemoryConfig() as the config parameter member.

    Values:

    enumerator `EMIF_SYNC_BANK_1` = 0x00000000U

      1 Bank SDRAM device

    enumerator `EMIF_SYNC_BANK_2` = 0x00000010U

      2 Bank SDRAM device

    enumerator `EMIF_SYNC_BANK_4` = 0x00000020U

      4 Bank SDRAM device

  enum `EMIF_SyncCASLatency`

    Values that can be passed to EMIF_setSyncMemoryConfig() as the config parameter member.

    Values:

    enumerator `EMIF_SYNC_CAS_LAT_2` = 0x00000500U

      SDRAM with CAS Latency 2.

    enumerator `EMIF_SYNC_CAS_LAT_3` = 0x00000700U

      SDRAM with CAS Latency 3.

  enum `EMIF_SyncPageSize`

    Values that can be passed to EMIF_setSyncMemoryConfig() as the config parameter member.

    Values:

    enumerator `EMIF_SYNC_COLUMN_WIDTH_8` = 0x00000000U

      256-word pages in SDRAM

    enumerator `EMIF_SYNC_COLUMN_WIDTH_9` = 0x00000001U

      512-word pages in SDRAM

    enumerator `EMIF_SYNC_COLUMN_WIDTH_10` = 0x00000002U

      1024-word pages in SDRAM

    enumerator `EMIF_SYNC_COLUMN_WIDTH_11` = 0x00000003U

      2048-word pages in SDRAM

  Functions

  void `EMIF_setAccessProtection`(uint32_t configBase, uint16_t access)

    Sets the access protection.

    This function sets the access protection for an EMIF instance from CPU and DMA. The

    access parameter can be any of EMIF_ACCPROT0_FETCHPROT, EMIF_ACCPROT0_CPUWRPROT EMIF_ACCPROT0_DMAWRPROT values or their combination. EMIF_ACCPROT0_DMAWRPROT value is valid as access parameter for EMIF1 instance only .
    Parameters

      - `configBase`: is the configuration address of the EMIF instance used.

      - `access`: is the required access protection configuration.

    Return

      None.

  void `EMIF_commitAccessConfig`(uint32_t configBase)

    Commits the lock configuration.

    This function commits the access protection for an EMIF instance from CPU & DMA.

    Parameters

      - `configBase`: is the configuration address of the EMIF instance used.

    Return

      None.

  void `EMIF_lockAccessConfig`(uint32_t configBase)

    Locks the write to access configuration fields.

    This function locks the write to access configuration fields i.e ACCPROT0 & Mselect fields, for an EMIF instance.

    Parameters

      - `configBase`: is the configuration address of the EMIF instance used.

    Return

      None.

  void `EMIF_unlockAccessConfig`(uint32_t configBase)

    Unlocks the write to access configuration fields.

    This function unlocks the write to access configuration fields such as ACCPROT0 & Mselect fields, for an EMIF instance.

    Parameters

      - `configBase`: is the configuration address of the EMIF instance used.

    Return

      None.

  void `EMIF_setAsyncMode`(uint32_t base, EMIF_AsyncCSOffset offset, EMIF_AsyncMode mode)

    Selects the asynchronous mode of operation.

    This function sets the mode of operation for asynchronous memory between Normal or Strobe mode. Valid values for param

    offset can be EMIF_ASYNC_CS2_OFFSET, EMIF_ASYNC_CS3_OFFSET & EMIF_ASYNC_C43_OFFSET for EMIF1 and EMIF_ASYNC_CS2_OFFSET for EMIF2. Valid values for param mode can be EMIF_ASYNC_STROBE_MODE or EMIF_ASYNC_NORMAL_MODE.
    Parameters

      - `base`: is the base address of the EMIF instance used.

      - `offset`: is the offset of asynchronous chip select of EMIF instance.

      - `mode`: is the desired mode of operation for external memory.

    Return

      None.

  void `EMIF_enableAsyncExtendedWait`(uint32_t base, EMIF_AsyncCSOffset offset)

    Enables the Extended Wait Mode.

    This function enables the extended wait mode for an asynchronous external memory.Valid values for param

    offset can be EMIF_ASYNC_CS2_OFFSET, EMIF_ASYNC_CS3_OFFSET & EMIF_ASYNC_C43_OFFSET for EMIF1 and EMIF_ASYNC_CS2_OFFSET for EMIF2.
    Parameters

      - `base`: is the base address of the EMIF instance used.

      - `offset`: is the offset of asynchronous chip select of the EMIF instance

    Return

      None.

  void `EMIF_disableAsyncExtendedWait`(uint32_t base, EMIF_AsyncCSOffset offset)

    Disables the Extended Wait Mode.

    This function disables the extended wait mode for an asynchronous external memory.Valid values for param

    offset can be EMIF_ASYNC_CS2_OFFSET, EMIF_ASYNC_CS3_OFFSET & EMIF_ASYNC_C43_OFFSET for EMIF1 and EMIF_ASYNC_CS2_OFFSET for EMIF2.
    Parameters

      - `base`: is the base address of the EMIF instance used.

      - `offset`: is the offset of asynchronous chip select of EMIF instance.

    Return

      None.

  void `EMIF_setAsyncWaitPolarity`(uint32_t base, EMIF_AsyncWaitPolarity polarity)

    Sets the wait polarity.

    This function sets the wait polarity for an asynchronous external memory. Valid values for param

    polarity can be EMIF_ASYNC_WAIT_POLARITY_LOW or EMIF_ASYNC_WAIT_POLARITY_HIGH.
    Parameters

      - `base`: is the base address of the EMIF instance used.

      - `polarity`: is desired wait polarity.

    Return

      None.

  void `EMIF_setAsyncMaximumWaitCycles`(uint32_t base, uint16_t value)

    Sets the Maximum Wait Cycles.

    This function sets the maximum wait cycles for extended asynchronous cycle. Valid values for parameter

    value lies b/w 0x0U-0xFFU or 0-255.
    Parameters

      - `base`: is the base address of the EMIF instance used.

      - `value`: is the desired maximum wait cycles.

    Return

      None.

  void `EMIF_setAsyncTimingParams`(uint32_t base, EMIF_AsyncCSOffset offset, const EMIF_AsyncTimingParams *tParam)

    Sets the Asynchronous Memory Timing Characteristics.

    This function sets timing characteristics for an external asynchronous memory to be interfaced. Valid values for param

    offset can be EMIF_ASYNC_CS2_OFFSET, EMIF_ASYNC_CS3_OFFSET and EMIF_ASYNC_C43_OFFSET for EMIF1 & EMIF_ASYNC_CS2_OFFSET for EMIF2.
    Parameters

      - `base`: is the base address of the EMIF instance used.

      - `offset`: is the offset of asynchronous chip select of EMIF instance.

      - `tParam`: is the desired timing parameters.

    Return

      None.

  void `EMIF_setAsyncDataBusWidth`(uint32_t base, EMIF_AsyncCSOffset offset, EMIF_AsyncDataWidth width)

    Sets the Asynchronous Data Bus Width.

    This function sets the data bus size for an external asynchronous memory to be interfaced. Valid values for param

    offset can be EMIF_ASYNC_CS2_OFFSET, EMIF_ASYNC_CS3_OFFSET & EMIF_ASYNC_C43_OFFSET for EMIF1 and EMIF_ASYNC_CS2_OFFSET for EMIF2. Valid values of param width can be EMIF_ASYNC_DATA_WIDTH_8, EMIF_ASYNC_DATA_WIDTH_16 or EMIF_ASYNC_DATA_WIDTH_32.
    Parameters

      - `base`: is the base address of the EMIF instance used.

      - `offset`: is the offset of asynchronous chip select of EMIF instance.

      - `width`: is the data bus width of the memory.

    Return

      None.

  void `EMIF_enableAsyncInterrupt`(uint32_t base, uint16_t intFlags)

    Enables the Asynchronous Memory Interrupts.

    This function enables the desired interrupts for an external asynchronous memory interface. Valid values for param

    intFlags can be EMIF_ASYNC_INT_AT, EMIF_ASYNC_INT_LT, EMIF_ASYNC_INT_WR or their combination.
    Parameters

      - `base`: is the base address of the EMIF instance used.

      - `intFlags`: is the mask for desired interrupts.

    Return

      None.

  void `EMIF_disableAsyncInterrupt`(uint32_t base, uint16_t intFlags)

    Disables the Asynchronous Memory Interrupts.

    This function disables the desired interrupts for an external asynchronous memory interface. Valid values for param

    intFlags can be EMIF_ASYNC_INT_AT, EMIF_ASYNC_INT_LT, EMIF_ASYNC_INT_WR or their combination.
    Parameters

      - `base`: is the base address of the EMIF instance used.

      - `intFlags`: is the mask for interrupts to be disabled.

    Return

      None.

  uint16_t `EMIF_getAsyncInterruptStatus`(uint32_t base)

    Gets the interrupt status.

    This function gets the interrupt status for an EMIF instance.

    Parameters

      - `base`: is the base address of the EMIF instance used.

    Return

      Returns the current interrupt status.

  void `EMIF_clearAsyncInterruptStatus`(uint32_t base, uint16_t intFlags)

    Clears the interrupt status for an EMIF instance.

    This function clears the interrupt status for an EMIF instance. The

    intFlags parameter can be any of EMIF_INT_MSK_SET_AT_MASK_SET, EMIF_INT_MSK_SET_LT_MASK_SET, or EMIF_INT_MSK_SET_WR_MASK_SET_M values or their combination.
    Parameters

      - `base`: is the base address of the EMIF instance used.

      - `intFlags`: is the mask for the interrupt status to be cleared.

    Return

      None.

  void `EMIF_setSyncTimingParams`(uint32_t base, const EMIF_SyncTimingParams *tParam)

    Sets the Synchronous Memory Timing Parameters.

    This function sets the timing characteristics for an external synchronous memory to be interfaced.

    Parameters

      - `base`: is the base address of an EMIF instance.

      - `tParam`: is parameters from memory datasheet in ns.

    Return

      None.

  void `EMIF_setSyncSelfRefreshExitTmng`(uint32_t base, uint16_t tXs)

    Sets the SDRAM Self Refresh Exit Timing.

    This function sets the self refresh exit timing for an external synchronous memory to be interfaced. tXs values must lie between 0x0U-0x1FU or 0-31.

    Parameters

      - `base`: is the base address of an EMIF instance.

      - `tXs`: is the desired timing value.

    Return

      None.

  void `EMIF_setSyncRefreshRate`(uint32_t base, uint16_t refRate)

    Sets the SDR Refresh Rate.

    This function sets the refresh rate for an external synchronous memory to be interfaced. Valid values for refRate lies b/w 0x0U-0x1FFFU or 0-8191.

    Parameters

      - `base`: is the base address of an EMIF instance.

      - `refRate`: is the refresh rate.

    Return

      None.

  void `EMIF_setSyncMemoryConfig`(uint32_t base, const EMIF_SyncConfig *config)

    Sets the Synchronous Memory configuration parameters.

    This function sets configuration parameters like CL, NM, IBANK and PAGESIZE for an external synchronous memory to be interfaced.

    Parameters

      - `base`: is the base address of the EMIF instance used.

      - `config`: is the desired configuration parameters.

    Return

      None.

  void `EMIF_enableSyncSelfRefresh`(uint32_t base)

    Enables Self Refresh.

    This function enables Self Refresh Mode for EMIF.

    Parameters

      - `base`: is the base address of the EMIF instance used.

    Return

      None.

  void `EMIF_disableSyncSelfRefresh`(uint32_t base)

    Disables Self Refresh.

    This function disables Self Refresh Mode for EMIF.

    Parameters

      - `base`: is the base address of the EMIF instance used.

    Return

      None.

  void `EMIF_enableSyncPowerDown`(uint32_t base)

    Enables Power Down.

    This function Enables Power Down Mode for synchronous memory to be interfaced.

    Parameters

      - `base`: is the base address of the EMIF instance used.

    Return

      None.

  void `EMIF_disableSyncPowerDown`(uint32_t base)

    Disables Power Down.

    This function disables Power Down Mode for synchronous memory to be interfaced.

    Parameters

      - `base`: is the base address of the EMIF instance used.

    Return

      None.

  void `EMIF_enableSyncRefreshInPowerDown`(uint32_t base)

    Enables Refresh in Power Down.

    This function enables Refresh in Power Down Mode for synchronous memory to be interfaced.

    Parameters

      - `base`: is the base address of the EMIF instance used.

    Return

      None.

  void `EMIF_disableSyncRefreshInPowerDown`(uint32_t base)

    Disables Refresh in Power Down.

    This function disables Refresh in Power Down Mode for synchronous memory to be interfaced.

    Parameters

      - `base`: is the base address of the EMIF instance used.

    Return

      None.

  uint32_t `EMIF_getSyncTotalAccesses`(uint32_t base)

    Gets total number of SDRAM accesses.

    This function returns total number of SDRAM accesses from a master(CPUx/CPUx.DMA).

    Parameters

      - `base`: is the base address of the EMIF instance used.

    Return

      Returns total number of accesses to SDRAM.

  uint32_t `EMIF_getSyncTotalActivateAccesses`(uint32_t base)

    Gets total number of SDRAM accesses which require activate command.

    This function returns total number of accesses to SDRAM which require activate command.

    Parameters

      - `base`: is the base address of the EMIF instance used.

    Return

      Returns total number of accesses to SDRAM which require activate.

  struct `EMIF_AsyncTimingParams`
    #include <emif.h>

    Values that can be passed to EMIF_setAsyncTimingParams() as the tParam parameter.

  struct `EMIF_SyncConfig`
    #include <emif.h>

    Values that can be passed to EMIF_setSyncMemoryConfig() as the config parameter.

  struct `EMIF_SyncTimingParams`
    #include <emif.h>

    Values that can be passed to EMIF_setSyncTimingParameters() as the tParam parameter.

The EMIF API include functions to set, lock/unlock, commit access configuration, set external asynchronous and synchronous memory configuration parameters and to manage asynchronous interrupts.

For interfacing asynchronous memories, functions are provided to configure EMIF registers to set mode of operation to strobe or normal mode, set enable/disable extended wait mode, set wait polarity, set maximum wait cycles, set async memory timing parameters, set memory data bus width as per the external memory to be interfaced and enable/disable, clear and get status for interrupts.

For interfacing synchronous memories, functions are provided to configure EMIF registers to set timing parameters, set self refresh exit timing, set refresh rate, set other memory specific parameters based on the external memory to be interfaced, enable/disable self refresh mode, enable/disable power down mode, enable/disable refresh in power down mode and to get total number of SDRAM accesses.

The code for this module is contained in driverlib/emif.c, with driverlib/emif.h containing the API declarations for use by applications.