This lets decode-dimms.pl decode almost all of the SPD data for DDR2 dimms.
Including all the detailed timing parameters with their standard tXXX
names, useful if one is trying to program a DDR memory controller for
example.
Index: decode-dimms.pl
===================================================================
--- i2c-tools/eeprom/decode-dimms.pl (revision 5132)
+++ i2c-tools/eeprom/decode-dimms.pl (working copy)
@@ -834,6 +834,20 @@
return $atime;
}
+sub ddrx_sdram_rtime($$$)
+{
+ my ($t, $b1, $b2) = @_;
+ my $rtime = $b1;
+ if($t == 2) {
+ $rtime += ($b2 & 1) * 256;
+ my @table = (0, .250, .330, .500, .660, .750);
+ $rtime += $table[($b2>>1)&7];
+ }
+ return $rtime;
+}
+
+sub tns($) { return sprintf("%3.2f ns", $_[0]); }
+
# Parameter: bytes 0-63
sub decode_ddr2_sdram($)
{
@@ -875,6 +889,40 @@
$bytes->[5] . "," . $bytes->[17];
}
+ printl "Banks x Rows x Columns x Bits",
+ join(' x ', $bytes->[17], $bytes->[3], $bytes->[4], $bytes->[6]);
+ printl "Ranks", ($bytes->[5]&7) + 1;
+
+ printl "SDRAM Device Width", $bytes->[13]." bits";
+
+ my @heights = ("< 25.4", "25.4", "25.4 - 30.0", "30.0", "30.5", ">
30.5");
+ printl "Module Height", $heights[$bytes->[5]>>5]." mm";
+ my @types = ("RDIMM", "UDIMM", "SO-DIMM", "Micro-DIMM",
+ "Mini-RDIMM", "Mini-UDIMM");
+ my @widths = (133.35, 133.25, 67.6, 45.5, 82.0, 82.0);
+ my @suptypes;
+ foreach $ii (0..5) {
+ push @suptypes, "$types[$ii] ($widths[$ii] mm)"
+ if($bytes->[20] & (1<<$ii));
+ }
+ printl "Module Type".(@suptypes>1?'s':''), join(', ', @suptypes);
+ printl "DRAM Package", $bytes->[5]&0x10 ? "Stack" : "Planar";
+
+ my @volts = ("TTL/5V Tolerant", "LVTTL", "HSTL 1.5V",
+ "SSTL 3.3V", "SSTL 2.5V", "SSTL 1.8V", "TBD");
+ printl "Voltage Interface Level", $volts[$bytes->[8]];
+
+ my @refresh = qw(Normal Reduced Reduced Extended Extended Extended);
+ my @refresht = (15.625,3.9,7.8,31.3,62.5,125);
+ printl "Refresh Rate",
+ "$refresh[$bytes->[12]&0x7f] ($refresht[$bytes->[12]&0x7f] us)".
+ ($bytes->[12]&0x80 ? " - Self Refresh" : "");
+
+ my @burst;
+ push @burst, 4 if ($bytes->[16] & 4);
+ push @burst, 8 if ($bytes->[16] & 8);
+ printl "Burst lengths supported", join(', ', @burst);
+
my $highestCAS = 0;
my %cas;
for ($ii = 2; $ii < 7; $ii++) {
@@ -899,31 +947,59 @@
ceil($tras/$ctime);
# latencies
- if (keys %cas) { $temp = join ', ', sort { $b <=> $a } keys %cas; }
+ if (keys %cas) { $temp = join ', ', map("${_}T",sort { $b <=> $a } keys
%cas); }
else { $temp = "None"; }
- printl "Supported CAS Latencies", $temp;
+ printl "Supported CAS Latencies (tCL)", $temp;
# timings
if (exists $cas{$highestCAS}) {
- printl "Minimum Cycle Time (CAS $highestCAS)",
- "$ctime ns";
- printl "Maximum Access Time (CAS $highestCAS)",
- ddr2_sdram_atime($bytes->[10]) . " ns";
+ printl "Minimum Cycle Time @ CAS $highestCAS (tCK min)",
+ tns($ctime);
+ printl "Maximum Access Time @ CAS $highestCAS (tAC)",
+ tns(ddr2_sdram_atime($bytes->[10]));
}
if (exists $cas{$highestCAS-1} && spd_written(@$bytes[23..24])) {
- printl "Minimum Cycle Time (CAS ".($highestCAS-1).")",
- ddr2_sdram_ctime($bytes->[23]) . " ns";
- printl "Maximum Access Time (CAS ".($highestCAS-1).")",
- ddr2_sdram_atime($bytes->[24]) . " ns";
+ printl "Minimum Cycle Time @ CAS ".($highestCAS-1),
+ tns(ddr2_sdram_ctime($bytes->[23]));
+ printl "Maximum Access Time @ CAS ".($highestCAS-1),
+ tns(ddr2_sdram_atime($bytes->[24]));
}
if (exists $cas{$highestCAS-2} && spd_written(@$bytes[25..26])) {
- printl "Minimum Cycle Time (CAS ".($highestCAS-2).")",
- ddr2_sdram_ctime($bytes->[25]) . " ns";
- printl "Maximum Access Time (CAS ".($highestCAS-2).")",
- ddr2_sdram_atime($bytes->[26]) . " ns";
+ printl "Minimum Cycle Time @ CAS ".($highestCAS-2),
+ tns(ddr2_sdram_ctime($bytes->[25]));
+ printl "Maximum Access Time @ CAS ".($highestCAS-2),
+ tns(ddr2_sdram_atime($bytes->[26]));
}
+ printl "Maximim Device Cycle Time (tCK max)",
+ tns(ddr2_sdram_ctime($bytes->[43]));
+
+ # Some timing information
+ prints("Timing Parameters");
+ printl "Address/Command Setup Time Before Clock (tIS)",
+ tns(ddr2_sdram_atime($bytes->[32]));
+ printl "Address/Command Hold Time After Clock (tIH)",
+ tns(ddr2_sdram_atime($bytes->[33]));
+ printl "Data Input Setup Time Before Strobe (tDS)",
+ tns(ddr2_sdram_atime($bytes->[34]));
+ printl "Data Input Hold Time After Strobe (tDH)",
+ tns(ddr2_sdram_atime($bytes->[35]));
+ printl "Minimum Row Precharge Delay (tRP)", tns($trp);
+ printl "Minimum Row Active to Row Active Delay (tRRD)",
+ tns($bytes->[28]/4);
+ printl "Minimum RAS# to CAS# Delay (tRCD)", tns($trcd);
+ printl "Minimum RAS# Pulse Width (tRAS)", tns($tras);
+ printl "Write Recovery Time (tWR)", tns($bytes->[36]/4);
+ printl "Minimum Write to Read CMD Delay (tWTR)", tns($bytes->[37]/4);
+ printl "Minimum Read to Pre-charge CMD Delay (tRTP)",
tns($bytes->[38]/4);
+ printl "Minimum Active to Auto-refresh Delay (tRC)",
+ tns(ddrx_sdram_rtime(2, $bytes->[41], ($bytes->[40]>>3)&0xe));
+ printl "Minimum Recovery Delay (tRFC)",
+ tns(ddrx_sdram_rtime(2, $bytes->[42], $bytes->[40]));
+ printl "Maximum DQS to DQ Skew (tDQSQ)", tns($bytes->[44]/100);
+ printl "Maximum Read Data Hold Skew (tQHS)", tns($bytes->[45]/100);
+ printl "PLL Relock Time", $bytes->[46] . " us" if ($bytes->[46]);
}
# Parameter: bytes 0-63
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