SPRUJ79 November 2024 F29H850TU
This section describes the function of each of the EMIF signals.
Pins | I/O | Description |
---|---|---|
EM1D[x:0] | I/O | EMIF data bus. |
EM1A[x:0] | O | EMIF address bus. When interfacing to an SDRAM device, these pins are primarily used to provide the row and column address to the SDRAM. The mapping from the internal program address to the external values placed on these pins is found in Table 14-14. EM1A[10] is also used during the PRE command to select which banks to deactivate. When interfacing to an asynchronous device, these pins are used in conjunction with the EM1BA pins to form the address that is sent to the device. The mapping from the internal program address to the external values placed on these pins is found in Section 14.2.6.1. |
EM1BA[1:0] | O | EMIF bank address. When interfacing to an SDRAM device, these pins are used to provide the bank address inputs to the SDRAM. The mapping from the internal program address to the external values placed on these pins is found in Table 14-14. When interfacing to an asynchronous device, these pins are used in conjunction with the EM1A pins to form the address that is sent to the device. The mapping from the internal program address to the external values placed on these pins is found in Section 14.2.6.1. |
EM1DQM[x:0] | O | Active-low byte
enables. When interfacing to SDRAM, these pins are connected to the DQM pins of the SDRAM to individually enable/disable each of the bytes in a data access. When interfacing to an asynchronous device, these pins are connected to byte enables. See Section 14.2.6 for details. |
EM1WE | O | Active-low write
enable. When interfacing to SDRAM, this pin is connected to the nWE pin of the SDRAM and is used to send commands to the device. When interfacing to an asynchronous device, this pin provides a signal which is active-low during the strobe period of an asynchronous write access cycle. |
Pins | I/O | Description |
---|---|---|
EM1CS0 | O | Active-low chip enable pin for SDRAM
devices. This pin is connected to the chip-select pin of the attached SDRAM device and is used for enabling/disabling commands. By default, EMIF keeps this SDRAM chip select active, even if EMIF is not interfaced with an SDRAM device. This pin is deactivated when accessing the asynchronous memory bank and is reactivated on completion of the asynchronous access. |
EM1RAS | O | Active-low row address
strobe pin. This pin is connected to the nRAS pin of the attached SDRAM device and is used for sending commands to the device. |
EM1CAS | O | Active-low column address
strobe pin. This pin is connected to the nCAS pin of the attached SDRAM device and is used for sending commands to the device. |
EM1SDCKE | O | Clock enable pin. This pin is connected to the CKE pin of the attached SDRAM device and is used for issuing the SELF REFRESH command which places the device in self-refresh mode. See Section 14.2.5.7 for details. |
EM1CLK | O | SDRAM clock pin. This pin is connected to the CLK pin of the attached SDRAM device. See Section 14.2.1 for details on the clock signal. |
Pins | I/O | Description |
---|---|---|
EM1CS[4:2] | O | Active-low chip enable pins for
asynchronous devices. These pins are meant to be connected to the chip-select pins of the attached asynchronous device. These pins are active only during accesses to the asynchronous memory. |
EM1WAIT | I | Wait input with programmable
polarity. A connected asynchronous device can extend the strobe period of an access cycle by asserting the EM1WAIT input to EMIF as described in Section 14.2.6.6. To enable this functionality, the EW bit in the asynchronous 1 configuration register (ASYNC_CS2_CFG) must be set to 1. In addition, the WP0 bit in ASYNC_CS2_CFG must be configured to define the polarity of the EM1WAIT pin. |
EM1OE | O | Active-low pin enable for asynchronous
devices. This pin provides a signal which is active-low during the strobe period of an asynchronous read access cycle. |
EM1RNW | O | EMIF asynchronous read/write
control. This pin stays high during reads and stays low during writes (same duration as CS). |