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litedram
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Enable auto-precharge

This commit is contained in:
2018-08-10 19:19:02 -04:00
parent 03a2ad6bdc
commit 74279ea26a
1 changed files with 21 additions and 5 deletions
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26
litedram/core/bankmachine.py
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@ -38,15 +38,18 @@ class BankMachine(Module):
self.cmd = cmd = stream.Endpoint(cmd_request_rw_layout(a, ba))
# # #
auto_precharge = Signal()
# Command buffer
cmd_buffer_layout = [("we", 1), ("adr", len(req.adr))]
cmd_buffer = stream.SyncFIFO(cmd_buffer_layout, settings.cmd_buffer_depth)
self.submodules += cmd_buffer
cmd_bufferPre = stream.SyncFIFO(cmd_buffer_layout, settings.cmd_buffer_depth)
cmd_buffer = stream.Buffer(cmd_buffer_layout) # 1 depth buffer to detect row change
self.submodules += cmd_buffer, cmd_bufferPre
self.comb += [
req.connect(cmd_buffer.sink, omit=["wdata_valid", "wdata_ready",
req.connect(cmd_bufferPre.sink, omit=["wdata_valid", "wdata_ready",
"rdata_valid", "rdata_ready",
"lock"]),
cmd_bufferPre.source.connect(cmd_buffer.sink),
cmd_buffer.source.ready.eq(req.wdata_ready | req.rdata_valid),
req.lock.eq(cmd_buffer.source.valid),
]
@ -75,7 +78,7 @@ class BankMachine(Module):
If(sel_row_adr,
cmd.a.eq(slicer.row(cmd_buffer.source.adr))
).Else(
cmd.a.eq(slicer.col(cmd_buffer.source.adr))
cmd.a.eq((auto_precharge << 10) | slicer.col(cmd_buffer.source.adr))
)
]
@ -86,6 +89,15 @@ class BankMachine(Module):
cmd.ready &
cmd.is_write))
# Auto Precharge
self.comb += [
If(cmd_bufferPre.source.valid & cmd_buffer.source.valid,
If(slicer.row(cmd_bufferPre.source.adr) != slicer.row(cmd_buffer.source.adr),
auto_precharge.eq(self.precharge_timer.done & (track_close == 0))
)
)
]
# Control and command generation FSM
self.submodules.fsm = fsm = FSM()
fsm.act("REGULAR",
@ -106,7 +118,10 @@ class BankMachine(Module):
req.rdata_valid.eq(cmd.ready),
cmd.is_read.eq(1)
),
cmd.cas.eq(1)
cmd.cas.eq(1),
If(cmd.ready & auto_precharge,
NextState("AUTOPRECHARGE")
)
)
).Else(
NextState("PRECHARGE")
@ -151,3 +166,4 @@ class BankMachine(Module):
)
fsm.delayed_enter("TRP", "ACTIVATE", settings.timing.tRP-1)
fsm.delayed_enter("TRCD", "REGULAR", settings.timing.tRCD-1)
fsm.delayed_enter("AUTOPRECHARGE", "TRP", precharge_time-1)