SPRUHM8K December 2013 – May 2024 F28377D-SEP , TMS320F28374D , TMS320F28375D , TMS320F28376D , TMS320F28377D , TMS320F28377D-EP , TMS320F28377D-Q1 , TMS320F28378D , TMS320F28379D , TMS320F28379D-Q1
The operation of the EMIF SDRAM interface is controlled by programming the appropriate configuration registers. This section describes the purpose and function of each configuration register, but Section 25.4 can be referred to for a more detailed description of each register, including the default registers values and bit-field positions. The following tables list the four such configuration registers, along with a description of each of their programmable fields.
| Parameter | Description |
|---|---|
| SR | This bit controls entering and exiting of the self-refresh mode |
| PD | This bit controls entering and exiting of the power-down mode. If both SR and PD bits are set, the EMIF goes into self-refresh mode. |
| PDWR | Perform refreshes during power down. Writing a 1 to this bit causes the EMIF to exit the power-down state and issue an AUTO REFRESH command every time Refresh May level is set. This bit must be set along with PD when entering power-down mode. |
| NM | Narrow Mode. This bit defines the width of the data bus between the EMIF and the attached SDRAM device. When set to 1, the data bus is set to 16-bits. When set to 0, the data bus is set to 32-bits. |
| CL | CAS latency. This field defines the number of clock cycles between when an SDRAM issues a READ command and when the first piece of data appears on the bus. The value in this field is sent to the attached SDRAM device using the LOAD MODE REGISTER command during the SDRAM initialization procedure as described in Section 25.2.5.4. Only, values of 2h (CAS latency = 2) and 3h (CAS latency = 3) are supported and must be written to this field. While updating the CL field, BIT11_9LOCK bit field must be set to 1 simultaneously. |
| IBANK | Number of Internal SDRAM
Banks. This field defines the number of banks
inside the attached SDRAM devices in the following
way:
|
| PAGESIZE | Page Size. This field
defines the internal page size of the attached
SDRAM devices in the following way:
|
| Parameter | Description |
|---|---|
| RR | Refresh Rate. This
field controls the rate at which attached SDRAM devices are refreshed. The following
equation can be used to determine the required value of RR for an SDRAM device:
|
| Parameter | Description |
|---|---|
| T_RFC | SDRAM Timing Parameters. These fields configure the EMIF to comply with the AC timing requirements of the attached SDRAM devices. This allows the EMIF to avoid violating SDRAM timing constraints and to more efficiently schedule operations. More details about each of these parameters can be found in the SDRAM_TR register description. These parameters must be set to satisfy the corresponding timing requirements found in the SDRAM data sheet. |
| T_RP | |
| T_RCD | |
| T_WR | |
| T_RAS | |
| T_RC | |
| T_RRD |
| Parameter | Description |
|---|---|
| T_XS | Self Refresh Exit Parameter. The T_XS field of this register informs the EMIF about the minimum number of EM1CLK cycles required between exiting self-refresh and issuing any command. This parameter must be set to satisfy the tXSR value for the attached SDRAM device. |