# 1:2 frequency-ratio DDR / LPDDR / DDR2 PHY for Spartan-6 # # Assert dfi_wrdata_en and present the data # on dfi_wrdata_mask/dfi_wrdata in the same # cycle as the write command. # # Assert dfi_rddata_en in the same cycle as the read # command. The data will come back on dfi_rddata # 5 cycles later, along with the assertion # of dfi_rddata_valid. # # This PHY only supports CAS latency 3 for DDR, LPDDR, DDR2 # and CAS latency 5/CAS write latency 6 for DDR3. # # Read commands must be sent on phase 0. # Write commands must be sent on phase 1. # from migen.fhdl.std import * from migen.genlib.record import * from misoclib.mem.sdram.phy.dfi import * from misoclib.mem import sdram class S6HalfRateDDRPHY(Module): def __init__(self, pads, module, rd_bitslip, wr_bitslip, dqs_ddr_alignment): if module.memtype not in ["DDR", "LPDDR", "DDR2", "DDR3"]: raise NotImplementedError("S6HalfRateDDRPHY only supports DDR, LPDDR, DDR2 and DDR3") addressbits = flen(pads.a) bankbits = flen(pads.ba) databits = flen(pads.dq) nphases = 2 if module.memtype == "DDR3": self.settings = sdram.PhySettings( memtype="DDR3", dfi_databits=2*databits, nphases=nphases, rdphase=0, wrphase=1, rdcmdphase=1, wrcmdphase=0, cl=5, cwl=6, read_latency=6, write_latency=2 ) else: self.settings = sdram.PhySettings( memtype=module.memtype, dfi_databits=2*databits, nphases=nphases, rdphase=0, wrphase=1, rdcmdphase=1, wrcmdphase=0, cl=3, read_latency=5, write_latency=0 ) self.module = module self.dfi = Interface(addressbits, bankbits, 2*databits, nphases) self.clk4x_wr_strb = Signal() self.clk4x_rd_strb = Signal() ### # sys_clk : system clk, used for dfi interface # sdram_half_clk : half rate sdram clk # sdram_full_wr_clk : full rate sdram write clk # sdram_full_rd_clk : full rate sdram read clk sd_sys = getattr(self.sync, "sys") sd_sdram_half = getattr(self.sync, "sdram_half") sys_clk = ClockSignal("sys") sdram_half_clk = ClockSignal("sdram_half") sdram_full_wr_clk = ClockSignal("sdram_full_wr") sdram_full_rd_clk = ClockSignal("sdram_full_rd") # # Command/address # # select active phase # sys_clk ----____----____ # phase_sel(nphases=2) 0 1 0 1 Half Rate phase_sel = Signal(log2_int(nphases)) phase_half = Signal.like(phase_sel) phase_sys = Signal.like(phase_half) sd_sys += phase_sys.eq(phase_half) sd_sdram_half += [ If(phase_half == phase_sys, phase_sel.eq(0), ).Else( phase_sel.eq(phase_sel+1) ), phase_half.eq(phase_half+1), ] # register dfi cmds on half_rate clk r_dfi = Array(Record(phase_cmd_description(addressbits, bankbits)) for i in range(nphases)) for n, phase in enumerate(self.dfi.phases): sd_sdram_half += [ r_dfi[n].reset_n.eq(phase.reset_n), r_dfi[n].odt.eq(phase.odt), r_dfi[n].address.eq(phase.address), r_dfi[n].bank.eq(phase.bank), r_dfi[n].cs_n.eq(phase.cs_n), r_dfi[n].cke.eq(phase.cke), r_dfi[n].cas_n.eq(phase.cas_n), r_dfi[n].ras_n.eq(phase.ras_n), r_dfi[n].we_n.eq(phase.we_n) ] # output cmds sd_sdram_half += [ pads.a.eq(r_dfi[phase_sel].address), pads.ba.eq(r_dfi[phase_sel].bank), pads.cke.eq(r_dfi[phase_sel].cke), pads.ras_n.eq(r_dfi[phase_sel].ras_n), pads.cas_n.eq(r_dfi[phase_sel].cas_n), pads.we_n.eq(r_dfi[phase_sel].we_n) ] # optional pads for name in "reset_n", "cs_n", "odt": if hasattr(pads, name): sd_sdram_half += getattr(pads, name).eq(getattr(r_dfi[phase_sel], name)) # # Bitslip # bitslip_cnt = Signal(4) bitslip_inc = Signal() sd_sys += [ If(bitslip_cnt == rd_bitslip, bitslip_inc.eq(0) ).Else( bitslip_cnt.eq(bitslip_cnt+1), bitslip_inc.eq(1) ) ] # # DQ/DQS/DM data # sdram_half_clk_n = Signal() self.comb += sdram_half_clk_n.eq(~sdram_half_clk) postamble = Signal() drive_dqs = Signal() dqs_t_d0 = Signal() dqs_t_d1 = Signal() dqs_o = Signal(databits//8) dqs_t = Signal(databits//8) self.comb += [ dqs_t_d0.eq(~(drive_dqs | postamble)), dqs_t_d1.eq(~drive_dqs), ] for i in range(databits//8): # DQS output self.specials += Instance("ODDR2", p_DDR_ALIGNMENT=dqs_ddr_alignment, p_INIT=0, p_SRTYPE="ASYNC", i_C0=sdram_half_clk, i_C1=sdram_half_clk_n, i_CE=1, i_D0=0, i_D1=1, i_R=0, i_S=0, o_Q=dqs_o[i] ) # DQS tristate cmd self.specials += Instance("ODDR2", p_DDR_ALIGNMENT=dqs_ddr_alignment, p_INIT=0, p_SRTYPE="ASYNC", i_C0=sdram_half_clk, i_C1=sdram_half_clk_n, i_CE=1, i_D0=dqs_t_d0, i_D1=dqs_t_d1, i_R=0, i_S=0, o_Q=dqs_t[i] ) # DQS tristate buffer if hasattr(pads, "dqs_n"): self.specials += Instance("OBUFTDS", i_I=dqs_o[i], i_T=dqs_t[i], o_O=pads.dqs[i], o_OB=pads.dqs_n[i], ) else: self.specials += Instance("OBUFT", i_I=dqs_o[i], i_T=dqs_t[i], o_O=pads.dqs[i] ) sd_sdram_half += postamble.eq(drive_dqs) d_dfi = [Record(phase_wrdata_description(nphases*databits)+phase_rddata_description(nphases*databits)) for i in range(2*nphases)] for n, phase in enumerate(self.dfi.phases): self.comb += [ d_dfi[n].wrdata.eq(phase.wrdata), d_dfi[n].wrdata_mask.eq(phase.wrdata_mask), d_dfi[n].wrdata_en.eq(phase.wrdata_en), d_dfi[n].rddata_en.eq(phase.rddata_en), ] sd_sys += [ d_dfi[nphases+n].wrdata.eq(phase.wrdata), d_dfi[nphases+n].wrdata_mask.eq(phase.wrdata_mask) ] drive_dq = Signal() drive_dq_n = [Signal() for i in range(2)] self.comb += drive_dq_n[0].eq(~drive_dq) sd_sys += drive_dq_n[1].eq(drive_dq_n[0]) dq_t = Signal(databits) dq_o = Signal(databits) dq_i = Signal(databits) dq_wrdata = [] for i in range(2): for j in reversed(range(nphases)): dq_wrdata.append(d_dfi[i*nphases+j].wrdata[:databits]) dq_wrdata.append(d_dfi[i*nphases+j].wrdata[databits:]) for i in range(databits): # Data serializer self.specials += Instance("OSERDES2", p_DATA_WIDTH=4, p_DATA_RATE_OQ="SDR", p_DATA_RATE_OT="SDR", p_SERDES_MODE="NONE", p_OUTPUT_MODE="SINGLE_ENDED", o_OQ=dq_o[i], i_OCE=1, i_CLK0=sdram_full_wr_clk, i_CLK1=0, i_IOCE=self.clk4x_wr_strb, i_RST=0, i_CLKDIV=sys_clk, i_D1=dq_wrdata[wr_bitslip+3][i], i_D2=dq_wrdata[wr_bitslip+2][i], i_D3=dq_wrdata[wr_bitslip+1][i], i_D4=dq_wrdata[wr_bitslip+0][i], o_TQ=dq_t[i], i_T1=drive_dq_n[(wr_bitslip+3)//4], i_T2=drive_dq_n[(wr_bitslip+2)//4], i_T3=drive_dq_n[(wr_bitslip+1)//4], i_T4=drive_dq_n[(wr_bitslip+0)//4], i_TRAIN=0, i_TCE=1, i_SHIFTIN1=0, i_SHIFTIN2=0, i_SHIFTIN3=0, i_SHIFTIN4=0, ) # Data deserializer self.specials += Instance("ISERDES2", p_DATA_WIDTH=4, p_DATA_RATE="SDR", p_BITSLIP_ENABLE="TRUE", p_SERDES_MODE="NONE", p_INTERFACE_TYPE="RETIMED", i_D=dq_i[i], i_CE0=1, i_CLK0=sdram_full_rd_clk, i_CLK1=0, i_IOCE=self.clk4x_rd_strb, i_RST=ResetSignal(), i_CLKDIV=sys_clk, i_BITSLIP=bitslip_inc, o_Q1=d_dfi[0*nphases+0].rddata[i+databits], o_Q2=d_dfi[0*nphases+0].rddata[i], o_Q3=d_dfi[0*nphases+1].rddata[i+databits], o_Q4=d_dfi[0*nphases+1].rddata[i], ) # Data buffer self.specials += Instance("IOBUF", i_I=dq_o[i], o_O=dq_i[i], i_T=dq_t[i], io_IO=pads.dq[i] ) dq_wrdata_mask = [] for i in range(2): for j in reversed(range(nphases)): dq_wrdata_mask.append(d_dfi[i*nphases+j].wrdata_mask[:databits//8]) dq_wrdata_mask.append(d_dfi[i*nphases+j].wrdata_mask[databits//8:]) for i in range(databits//8): # Mask serializer self.specials += Instance("OSERDES2", p_DATA_WIDTH=4, p_DATA_RATE_OQ="SDR", p_DATA_RATE_OT="SDR", p_SERDES_MODE="NONE", p_OUTPUT_MODE="SINGLE_ENDED", o_OQ=pads.dm[i], i_OCE=1, i_CLK0=sdram_full_wr_clk, i_CLK1=0, i_IOCE=self.clk4x_wr_strb, i_RST=0, i_CLKDIV=sys_clk, i_D1=dq_wrdata_mask[wr_bitslip+3][i], i_D2=dq_wrdata_mask[wr_bitslip+2][i], i_D3=dq_wrdata_mask[wr_bitslip+1][i], i_D4=dq_wrdata_mask[wr_bitslip+0][i], i_TRAIN=0, i_TCE=0, i_SHIFTIN1=0, i_SHIFTIN2=0, i_SHIFTIN3=0, i_SHIFTIN4=0, ) # # DQ/DQS/DM control # # write wrdata_en = Signal() self.comb += wrdata_en.eq(optree("|", [d_dfi[p].wrdata_en for p in range(nphases)])) if module.memtype == "DDR3": r_drive_dq = Signal(self.settings.cwl-1) sd_sdram_half += r_drive_dq.eq(Cat(wrdata_en, r_drive_dq)) self.comb += drive_dq.eq(r_drive_dq[self.settings.cwl-2]) else: self.comb += drive_dq.eq(wrdata_en) wrdata_en_d = Signal() sd_sys += wrdata_en_d.eq(wrdata_en) r_dfi_wrdata_en = Signal(max(self.settings.cwl, self.settings.cl)) sd_sdram_half += r_dfi_wrdata_en.eq(Cat(wrdata_en_d, r_dfi_wrdata_en)) if module.memtype == "DDR3": self.comb += drive_dqs.eq(r_dfi_wrdata_en[self.settings.cwl-1]) else: self.comb += drive_dqs.eq(r_dfi_wrdata_en[1]) # read rddata_en = Signal() self.comb += rddata_en.eq(optree("|", [d_dfi[p].rddata_en for p in range(nphases)])) rddata_sr = Signal(self.settings.read_latency) sd_sys += rddata_sr.eq(Cat(rddata_sr[1:self.settings.read_latency], rddata_en)) for n, phase in enumerate(self.dfi.phases): self.comb += [ phase.rddata.eq(d_dfi[n].rddata), phase.rddata_valid.eq(rddata_sr[0]), ]