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tRRD is specified incorrectly.

This commit is contained in:
2018-10-11 16:57:24 -04:00
parent acef5f523b
commit 055cbdbc43
1 changed files with 4 additions and 18 deletions
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22
litedram/modules.py
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@ -41,7 +41,7 @@ class SDRAMModule:
tWTR=self.ck_ns_to_cycles(*self.get("tWTR")),
tFAW=None if self.get("tFAW") is None else self.ck_ns_to_cycles(*self.get("tFAW")),
tCCD=None if self.get("tCCD") is None else self.ck_ns_to_cycles(*self.get("tCCD")),
tRRD=None if self.get("tRRD") is None else self.ns_to_cycles_trrd(self.get("tRRD")),
tRRD=None if self.get("tRRD") is None else self.ck_ns_to_cycles(*self.get("tRRD")),
tRC=None if self.get("tRC") is None else self.ns_to_cycles(self.get("tRC")),
tRAS=None if self.get("tRAS") is None else self.ns_to_cycles(self.get("tRAS"))
)
@ -66,20 +66,6 @@ class SDRAMModule:
except:
return None
def ns_to_cycles_trrd(self, t):
lower_bound = {
"1:1" : 4,
"1:2" : 2,
"1:4" : 1
}
if (t is None):
if self.memtype == "DDR3":
return lower_bound[self.rate]
else:
return 0 #Review: Is this needed for DDR2 and below?
return max(lower_bound[self.rate], self.ns_to_cycles(t, margin=False))
def ns_to_cycles(self, t, margin=True):
clk_period_ns = 1e9/self.clk_freq
if margin:
@ -216,7 +202,7 @@ class MT41J128M16(SDRAMModule):
nrows = 16384
ncols = 1024
# timings
technology_timings = _TechnologyTimings(tREFI=64e6/8192, tWTR=(4, 7.5), tCCD=(4, None), tRRD=10)
technology_timings = _TechnologyTimings(tREFI=64e6/8192, tWTR=(4, 7.5), tCCD=(4, None), tRRD=(4, 10))
speedgrade_timings = {
"800": _SpeedgradeTimings(tRP=13.1, tRCD=13.1, tWR=13.1, tRFC=64, tFAW=(None, 50), tRC=50.625, tRAS=37.5),
"1066": _SpeedgradeTimings(tRP=13.1, tRCD=13.1, tWR=13.1, tRFC=86, tFAW=(None, 50), tRC=50.625, tRAS=37.5),
@ -237,7 +223,7 @@ class MT41J256M16(SDRAMModule):
nrows = 32768
ncols = 1024
# timings
technology_timings = _TechnologyTimings(tREFI=64e6/8192, tWTR=(4, 7.5), tCCD=(4, None), tRRD=10)
technology_timings = _TechnologyTimings(tREFI=64e6/8192, tWTR=(4, 7.5), tCCD=(4, None), tRRD=(4,10))
speedgrade_timings = {
"800": _SpeedgradeTimings(tRP=13.1, tRCD=13.1, tWR=13.1, tRFC=139, tFAW=(None, 50), tRC=50.625, tRAS=37.5),
"1066": _SpeedgradeTimings(tRP=13.1, tRCD=13.1, tWR=13.1, tRFC=138, tFAW=(None, 50), tRC=50.625, tRAS=37.5),
@ -262,7 +248,7 @@ class K4B2G1646FBCK0(SDRAMModule): ### TODO: optimize and revalidate all timing
tREFI = 7800 # 3900 refresh more often at 85C+
tWTR = (14, 35)
tCCD = (4, None)
tRRD = 10 # 4 * clk = 10ns
tRRD = (4, 10) # 4 * clk = 10ns
# speedgrade related timings
# DDR3-1600
tRP_1600 = 13.125