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HFOSC trimming info

This commit is contained in:
David Shah 2017-12-06 17:48:15 +00:00
parent 9e81ac7786
commit 77eafa89b4
2 changed files with 20 additions and 1 deletions
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8
docs/ultraplus.html
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@ -205,6 +205,14 @@ The <span style="font-family:monospace">CLKHF</span> output of SB_HFOSC is conne
<p>Configuration bit <span style="font-family:monospace">CLKHF_DIV[1]</span> maps to DSP1 tile (0, 16) config bit <span style="font-family:monospace">CBIT_4</span>, and
<span style="font-family:monospace">CLKHF_DIV[0]</span> maps to DSP1 tile (0, 16) config bit <span style="font-family:monospace">CBIT_3</span>.</p>
<p>There is also an undocumented trimming function of the HFOSC, using the ports <span style="font-family:monospace">TRIM0</span> through <span style="font-family:monospace">TRIM9</span>. This can only be accessed directly in iCECUBE if you modify the standard cell library. However
if you set the attribute <span style="font-family:monospace">VPP_2V5_TO_1P8V</span> (which itself is not that well documented either) to 1 on the top level module, then the configuration bit
<span style="font-family:monospace">CBIT_5</span> of (0, 16) is set; and <span style="font-family:monospace">TRIM8</span> and <span style="font-family:monospace">TRIM4</span> are connected to
the same net as <span style="font-family:monospace">CLKHFPU</span>.</p>
<p><span style="font-family:monospace">TRIM[3:0]</span> connect to <span style="font-family:monospace">(25, 28, lutff_[7:4]/in_0)</span> and <span style="font-family:monospace">TRIM[9:4]</span>
connect to <span style="font-family:monospace">(25, 29, lutff_[5:0]/in_3)</span>. <span style="font-family:monospace">CBIT_5</span> of (0, 16) must be set to enable trimming. The trim range
on the device used for testing was from 30.1 to 75.9 MHz. TRIM9 seemed to have no effect, the other inputs could broadly be considered to form a binary word, however it appeared neither linear
nor even monotonic.</p>
<h3>SB_LFOSC</h3>
<p>The <span style="font-family:monospace">CLKLFPU</span> input connects through IPConnect tile (25, 29) input <span style="font-family:monospace">lutff_0/in_1</span>;
and the <span style="font-family:monospace">CLKLFEN</span> input connects through input <span style="font-family:monospace">lutff_7/in_3</span> of the same tile.<br/>

13
icebox/icebox.py
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@ -4695,8 +4695,19 @@ extra_cells_db = {
"CLKHFEN": (0, 29, "lutff_7/in_3"),
"CLKHF": (0, 29, "glb_netwk_4"),
"CLKHF_FABRIC": (0, 28, "slf_op_7"),
"TRIM0": (25, 28, "lutff_4/in_0"),
"TRIM1": (25, 28, "lutff_5/in_0"),
"TRIM2": (25, 28, "lutff_6/in_0"),
"TRIM3": (25, 28, "lutff_7/in_0"),
"TRIM4": (25, 29, "lutff_0/in_3"),
"TRIM5": (25, 29, "lutff_1/in_3"),
"TRIM6": (25, 29, "lutff_2/in_3"),
"TRIM7": (25, 29, "lutff_3/in_3"),
"TRIM8": (25, 29, "lutff_4/in_3"),
"TRIM9": (25, 29, "lutff_5/in_3"),
"CLKHF_DIV_1": (0, 16, "CBIT_4"),
"CLKHF_DIV_0": (0, 16, "CBIT_3")
"CLKHF_DIV_0": (0, 16, "CBIT_3"),
"TRIM_EN": (0, 16, "CBIT_5")
},
("LFOSC", (25, 31, 1)) : {
"CLKLFPU": (25, 29, "lutff_0/in_1"),