| Distributed RAMs (DRAM / SLICEM) | |
| ================================ | |
| The SLICEM site can turn the 4 LUT6s into distributed RAMs. There are a number of modes, each element is either a 64x1 or a 32x2 distributed RAM (DRAM). The individual elements can be combined into either a 128x1 or 256x1 DRAM. | |
| Functions | |
| --------- | |
| Modes | |
| ~~~~~ | |
| Some modes can be enabled at the single LUT level. The following modes are: | |
| - 32x2 Single port (32x2S) | |
| - 32x2 Dual port (32x2D) | |
| - 64x1 Single port (64x1S) | |
| - 64x1 Dual port (64x1D) | |
| Some modes are SLICEM wide: | |
| - 128x1 Single port (128x1S) | |
| - 128x1 Dual port (128x1D) | |
| - 256x1 | |
| Ports | |
| ~~~~~ | |
| Each LUT element when operating in RAM mode is a DPRAM64. | |
| +------------+------------+-----------+--------------+ | |
| | Port name | Direction | Width | Description | | |
| +============+============+===========+==============+ | |
| | WA | IN | 8 | Write address| | |
| +------------+------------+-----------+--------------+ | |
| | A | IN | 6 | Read address | | |
| +------------+------------+-----------+--------------+ | |
| | DI | IN | 2 | Data input | | |
| +------------+------------+-----------+--------------+ | |
| | WE | IN | 1 | Write enable | | |
| +------------+------------+-----------+--------------+ | |
| | CLK | IN | 1 | Clock | | |
| +------------+------------+-----------+--------------+ | |
| | O6 | OUT | 1 | Data output 1| | |
| +------------+------------+-----------+--------------+ | |
| | O5 | OUT | 1 | Data output 2| | |
| +------------+------------+-----------+--------------+ | |
| Configuration | |
| ------------- | |
| The configuration for the DRAM is found in the following segbits: | |
| - ALUT.RAM | |
| - ALUT.SMALL | |
| - ADI1MUX.AI | |
| - BLUT.RAM | |
| - BLUT.SMALL | |
| - BDI1MUX.BI | |
| - CLUT.RAM | |
| - CLUT.SMALL | |
| - CDI1MUX.CI | |
| - DLUT.RAM | |
| - DLUT.SMALL | |
| - WA7USED | |
| - WA8USED | |
| In order to use DRAM in a SLICEM, the DLUT in the SLICEM must be a RAM (e.g. DLUT.RAM). | |
| In addition the DLUT can never be a dual port RAM because the write address lines for the DLUT are also the read address lines. | |
| Segbits for modes | |
| ~~~~~~~~~~~~~~~~~ | |
| The following table shows the features required for each mode type for each LUT. | |
| +------+------------+------------+------------+----------+ | |
| | LUTs | 32x2S | 32x2D | 64x1S | 64x1D | | |
| +------+------------+------------+------------+----------+ | |
| | D | DLUT.RAM | N/A | DLUT.RAM | N/A | | |
| | | | | | | | |
| | | DLUT.SMALL | | | | | |
| +------+------------+------------+------------+----------+ | |
| | C | CLUT.RAM | CLUT.RAM | CLUT.RAM | CLUT.RAM | | |
| | | | | | | | |
| | | CLUT.SMALL | CLUT.SMALL | CDI1MUX.CI | | | |
| | | | | | | | |
| | | CDI1MUX.CI | | | | | |
| +------+------------+------------+------------+----------+ | |
| | B | BLUT.RAM | BLUT.RAM | BLUT.RAM | BLUT.RAM | | |
| | | | | | | | |
| | | BLUT.SMALL | BLUT.SMALL | BDI1MUX.CI | | | |
| | | | | | | | |
| | | BDI1MUX.CI | | | | | |
| +------+------------+------------+------------+----------+ | |
| | A | ALUT.RAM | ALUT.RAM | ALUT.RAM | ALUT.RAM | | |
| | | | | | | | |
| | | ALUT.SMALL | ALUT.SMALL | ADI1MUX.CI | | | |
| | | | | | | | |
| | | ADI1MUX.CI | | | | | |
| +------+------------+------------+------------+----------+ | |
| Ports for modes | |
| ~~~~~~~~~~~~~~~ | |
| In each mode, how the ports are used vary. The following table show the relationship between the LUT mode and ports. | |
| +------+-------------------------------------+----------------------------+----------------------------------------+-------------------------------+ | |
| | LUTs | 32x2S | 32x2D | 64x1S | 64x1D | | |
| +------+-------------------------------------+----------------------------+----------------------------------------+-------------------------------+ | |
| | D | WA[4:0] = A[4:0] = {D5,D4,D3,D2,D1} | N/A | WA[5:0] = A[5:0] = {D6,D5,D4,D3,D2,D1} | N/A | | |
| | | | | | | | |
| | | DI[1:0] = {DX, DI} | | DI[0] = DI | | | |
| +------+-------------------------------------+----------------------------+----------------------------------------+-------------------------------+ | |
| | C | WA[4:0] = A[4:0] = {C5,C4,C3,C2,C1} | WA[4:0] = {D5,D4,D3,D2,D1} | WA[5:0] = A[5:0] = {C6,C5,C4,C3,C2,C1} | WA[5:0] = {D6,D5,D4,D3,D2,D1} | | |
| | | | | | | | |
| | | DI[1:0] = {CX, CI} | A[4:0] = {C5,C4,C3,C2,C1} | | A[5:0] = {C6,C5,C4,C3,C2,C1} | | |
| | | | | | | | |
| | | | DI[1:0] = {CX,DI} | DI[0] = CI | DI[0] = DI | | |
| +------+-------------------------------------+----------------------------+----------------------------------------+-------------------------------+ | |
| | B | WA[4:0] = A[4:0] = {B5,B4,B3,B2,B1} | WA[4:0] = {D5,D4,D3,D2,D1} | WA[5:0] = A[5:0] = {B6,B5,B4,B3,B2,B1} | WA[5:0] = {D6,D5,D4,D3,D2,D1} | | |
| | | | | | | | |
| | | | A[4:0] = {B5,B4,B3,B2,B1} | | A[5:0] = {B6,B5,B4,B3,B2,B1} | | |
| | | DI[1:0] = {BX, BI} | | DI[0] = BI | | | |
| | | | DI[1:0] = {BX,DI} | | DI[0] = DI | | |
| +------+-------------------------------------+----------------------------+----------------------------------------+-------------------------------+ | |
| | A | WA[4:0] = A[4:0] = {A5,A4,A3,A2,A1} | WA[4:0] = {D5,D4,D3,D2,D1} | WA[5:0] = A[5:0] = {A6,A5,A4,A3,A2,A1} | WA[5:0] = {D6,D5,D4,D3,D2,D1} | | |
| | | | | | | | |
| | | DI[1:0] = {AX, AI} | A[4:0] = {A5,A4,A3,A2,A1} | DI[0] = AI | A[5:0] = {A6,A5,A4,A3,A2,A1} | | |
| | | | | | | | |
| | | | DI[1:0] = {AX,BLUT.DI[0]} | | DI[0] = BLUT.DI[0] | | |
| +------+-------------------------------------+----------------------------+----------------------------------------+-------------------------------+ | |
| Techlib macros | |
| ~~~~~~~~~~~~~~ | |
| The tech library exposes the following aggregate modes, which are accomplished with the following combinations. | |
| +----------+--------------+--------------+--------------+--------------+ | |
| | Macro | Option 1 | Option 2 | Option 3 | Option 4 | | |
| +----------+--------------+--------------+--------------+--------------+ | |
| | RAM32M | DLUT = 32x2S | | | | | |
| | | | | | | | |
| | | CLUT = 32x2D | | | | | |
| | | | | | | | |
| | | BLUT = 32x2D | | | | | |
| | | | | | | | |
| | | ALUT = 32x2D | | | | | |
| +----------+--------------+--------------+--------------+--------------+ | |
| | RAM32X1D | DLUT = 32x2S | BLUT = 32x2S | | | | |
| | | | | | | | |
| | | CLUT = 32x2D | ALUT = 32x2D | | | | |
| +----------+--------------+--------------+--------------+--------------+ | |
| | RAM32X1S | DLUT = 32x1S | CLUT = 32x1S | BLUT = 32x1S | ALUT = 32x1S | | |
| +----------+--------------+--------------+--------------+--------------+ | |
| | RAM32X2S | DLUT = 32x2S | BLUT = 32x2S | | | | |
| | | | | | | | |
| | | CLUT = 32x2D | ALUT = 32x2D | | | | |
| +----------+--------------+--------------+--------------+--------------+ | |
| | RAM64M | DLUT = 64x1S | | | | | |
| | | | | | | | |
| | | CLUT = 64x1D | | | | | |
| | | | | | | | |
| | | BLUT = 64x1D | | | | | |
| | | | | | | | |
| | | ALUT = 64x1D | | | | | |
| +----------+--------------+--------------+--------------+--------------+ | |
| | RAM64X1D | DLUT = 64x1S | BLUT = 64x1S | | | | |
| | | | | | | | |
| | | CLUT = 64x1D | ALUT = 64x1D | | | | |
| +----------+--------------+--------------+--------------+--------------+ | |
| | RAM64X1S | DLUT = 64x1S | CLUT = 64x1S | BLUT = 64x1S | ALUT = 64x1S | | |
| +----------+--------------+--------------+--------------+--------------+ | |