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diff --git a/docs/ram_tile.html b/docs/ram_tile.html deleted file mode 100644 index 2264966..0000000 --- a/docs/ram_tile.html +++ /dev/null @@ -1,104 +0,0 @@ -<!DOCTYPE html> -<html><head><meta charset="UTF-8"> -<style> -.ctab { - margin-left: auto; - margin-right: auto; - border: 1px solid gray; -} -.ctab td, .ctab th { - padding: 3px; - border: 1px solid gray; -} -</style> -<title>Project IceStorm – RAM Tile Documentation</title> -</head><body> -<h1>Project IceStorm – RAM Tile Documentation</h1> - -<p> -<i><a href=".">Project IceStorm</a> aims at documenting the bitstream format of Lattice iCE40 -FPGAs and providing simple tools for analyzing and creating bitstream files. -This is work in progress.</i> -</p> - -<h2>Span-4 and Span-12 Wires</h2> - -<p> -Regarding the Span-4 and Span-12 Wires a RAM tile behaves exactly like a LOGIC tile. So for simple -applications that do not need the block ram resources, the RAM tiles can be handled like a LOGIC -tiles without logic cells in them. -</p> - -<h2>Block RAM Resources</h2> - -<p> -A pair or RAM tiles (odd and even y-coordinates) provides an interface to a block ram cell. Like with -LOGIC tiles, signals entering the RAM tile have to be routed over local tracks to the block ram -inputs. Tiles with odd y-coordinates are "bottom" RAM Tiles (RAMB Tiles), and tiles with even y-coordinates -are "top" RAM Tiles (RAMT Tiles). Each pair of RAMB/RAMT tiles implements a <span style="font-family:monospace">SB_RAM40_4K</span> cell. The -cell ports are spread out over the two tiles as follows: -</p> - -<table class="ctab"> -<tr><th>SB_RAM40_4K</th><th>RAMB Tile</th><th>RAMT Tile</th></tr> -<tr><td><span style="font-family:monospace">RDATA[15:0]</span></td><td><span style="font-family:monospace">RDATA[7:0]</span></td><td><span style="font-family:monospace">RDATA[15:8]</span></td></tr> -<tr><td><span style="font-family:monospace">RADDR[10:0]</span></td><td><span style="font-family:monospace">-</span></td><td><span style="font-family:monospace">RADDR[10:0]</span></td></tr> -<tr><td><span style="font-family:monospace">WADDR[10:0]</span></td><td><span style="font-family:monospace">WADDR[10:0]</span></td><td><span style="font-family:monospace">-</span></td></tr> -<tr><td><span style="font-family:monospace">MASK[15:0]</span></td><td><span style="font-family:monospace">MASK[7:0]</span></td><td><span style="font-family:monospace">MASK[15:8]</span></td></tr> -<tr><td><span style="font-family:monospace">WDATA[15:0]</span></td><td><span style="font-family:monospace">WDATA[7:0]</span></td><td><span style="font-family:monospace">WDATA[15:8]</span></td></tr> -<tr><td><span style="font-family:monospace">RCLKE</span></td><td><span style="font-family:monospace">-</span></td><td><span style="font-family:monospace">RCLKE</span></td></tr> -<tr><td><span style="font-family:monospace">RCLK</span></td><td><span style="font-family:monospace">-</span></td><td><span style="font-family:monospace">RCLK</span></td></tr> -<tr><td><span style="font-family:monospace">RE</span></td><td><span style="font-family:monospace">-</span></td><td><span style="font-family:monospace">RE</span></td></tr> -<tr><td><span style="font-family:monospace">WCLKE</span></td><td><span style="font-family:monospace">WCLKE</span></td><td><span style="font-family:monospace">-</span></td></tr> -<tr><td><span style="font-family:monospace">WCLK</span></td><td><span style="font-family:monospace">WCLK</span></td><td><span style="font-family:monospace">-</span></td></tr> -<tr><td><span style="font-family:monospace">WE</span></td><td><span style="font-family:monospace">WE</span></td><td><span style="font-family:monospace">-</span></td></tr> -</table> - -<p> -The configuration bit <span style="font-family:monospace">RamConfig PowerUp</span> in the RAMB tile enables the memory. This bit -is active-low in 1k chips, i.e. an unused RAM block has only this bit set. Note that <span style="font-family:monospace">icebox_explain.py</span> -will ignore all RAMB tiles that only have the <span style="font-family:monospace">RamConfig PowerUp</span> bit set. -</p> - -<p> -In 8k chips the <span style="font-family:monospace">RamConfig PowerUp</span> bit is active-high. So an unused RAM block has all bits cleared -in the 8k config bitstream. -</p> - -<p> -The <span style="font-family:monospace">RamConfig CBIT_*</span> bits in the RAMT tile configure the read/write width of the -memory. Those bits map to the <span style="font-family:monospace">SB_RAM40_4K</span> cell parameters as follows: -</p> - -<table class="ctab"> -<tr><th>SB_RAM40_4K</th><th>RAMT Config Bit</th></tr> -<tr><td><span style="font-family:monospace">WRITE_MODE[0]</span></td><td><span style="font-family:monospace">RamConfig CBIT_0</span></td></tr> -<tr><td><span style="font-family:monospace">WRITE_MODE[1]</span></td><td><span style="font-family:monospace">RamConfig CBIT_1</span></td></tr> -<tr><td><span style="font-family:monospace">READ_MODE[0]</span></td><td><span style="font-family:monospace">RamConfig CBIT_2</span></td></tr> -<tr><td><span style="font-family:monospace">READ_MODE[1]</span></td><td><span style="font-family:monospace">RamConfig CBIT_3</span></td></tr> -</table> - -<p> -The read/write mode selects the width of the read/write port: -</p> - -<table class="ctab"> -<tr><th>MODE</th><th>DATA Width</th><th>Used WDATA/RDATA Bits</th></tr> -<tr><td>0</td><td>16</td><td>15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0</td></tr> -<tr><td>1</td><td>8</td><td>14, 12, 10, 8, 6, 4, 2, 0</td></tr> -<tr><td>2</td><td>4</td><td>13, 9, 5, 1</td></tr> -<tr><td>3</td><td>2</td><td>11, 3</td></tr> -</table> - -<p> -The <span style="font-family:monospace">NegClk</span> bit in the RAMB tile (1k die) or RAMT tile (other devices) negates the polarity of the <span style="font-family:monospace">WCLK</span> port, -and the <span style="font-family:monospace">NegClk</span> bit in the RAMT (1k die) or RAMB tile (other devices) tile negates the polarity of the <span style="font-family:monospace">RCLK</span> port. -</p> - -<p> -A logic tile sends the output of its eight logic cells to its neighbour tiles. A RAM tile does the same thing -with the <span style="font-family:monospace">RDATA</span> outputs. Each RAMB tile exports its <span style="font-family:monospace">RDATA[7:0]</span> outputs and each RAMT tile -exports its <span style="font-family:monospace">RDATA[15:8]</span> outputs via this mechanism. -</p> - -</body></html> |
