SPRUHZ7K August 2015 – April 2024 AM5706 , AM5708 , AM5716 , AM5718 , AM5718-HIREL
For EMIF_SDRAM_CONFIG[28:27] IBANK_POS = 0 and EMIF_SDRAM_CONFIG_2[27] EBANK_POS = 0, Table 15-78 lists which source address bits (MAddr) are mapped to the SDRAM row, column, bank and chip select bits for all combinations of IBANK, EBANK and PAGESIZE.
| MAddr[31:N] N = 1 if 16-bit data bus width; N = 2 if 32-bit data bus width | |||||||
|---|---|---|---|---|---|---|---|
| row address | chip select | bank address | column address | ||||
| ROWSIZE value | row width (bits) | EBANK value | chip select width (bits) | IBANK value | bank[2:0] width (bits) | PAGESIZE value | col width (bits) |
| In this case the ROWSIZE bit field is not used | 16 | 0 | 0 | 0 | 0 | 0 | 8 |
| 1 | 1 | 1 | 1 | 1 | 9 | ||
| 2 | 2 | 2 | 10 | ||||
| 3 | 3 | 3 | 11 | ||||
The ROWSIZE bit field is unused in case of IBANK_POS = 0 and EBANK_POS = 0.
For EMIF_SDRAM_CONFIG[28:27] IBANK_POS = 0, the effect of the address-mapping scheme is that as the source address increments across the SDRAM pages, EMIF moves to page with the same number as in the previous bank within the current device (CSN0). This movement across the banks continues until the same page is accessed in all banks and then EMIF moves to the next page in the first bank if the EMIF_SDRAM_CONFIG[3] EBANK bit is set to 0x0. If EBANK is set to 0x1 the EMIF proceeds to the same page in the next device (CSN1) and then continues until the same page is accessed in all banks before modifying the next page of the first device (CSN0).The EMIF uses this movement across chip selects and internal banks while remaining on the same page to maximize the number of the open SDRAM banks within the overall SDRAM space.
Thus, the EMIF can keep a maximum of 16 banks (8 internal banks across two chip selects) open at a time, and can interleave among all of them.