litex/targets/de0nano.py

from migen.fhdl.std import *
from migen.bus import wishbone

from misoclib.cpu.peripherals import gpio
from misoclib.mem import sdram
from misoclib.mem.sdram.module import IS42S16160
from misoclib.mem.sdram.phy import gensdrphy
from misoclib.mem.sdram.core.lasmicon import LASMIconSettings
from misoclib.com import uart
from misoclib.soc.sdram import SDRAMSoC

class _PLL(Module):
	def __init__(self, period_in, name, phase_shift, operation_mode):
		self.clk_in = Signal()
		self.clk_out = Signal()

		self.specials += Instance("ALTPLL",
			p_bandwidth_type = "AUTO",
			p_clk0_divide_by = 1,
			p_clk0_duty_cycle = 50,
			p_clk0_multiply_by = 2,
			p_clk0_phase_shift = "{}".format(str(phase_shift)),
			p_compensate_clock = "CLK0",
			p_inclk0_input_frequency = int(period_in*1000),
			p_intended_device_family = "Cyclone IV E",
			p_lpm_hint = "CBX_MODULE_PREFIX={}_pll".format(name),
			p_lpm_type = "altpll",
			p_operation_mode = operation_mode,
			i_inclk=self.clk_in,
			o_clk=self.clk_out,
			i_areset=0,
			i_clkena=0x3f,
			i_clkswitch=0,
			i_configupdate=0,
			i_extclkena=0xf,
			i_fbin=1,
			i_pfdena=1,
			i_phasecounterselect=0xf,
			i_phasestep=1,
			i_phaseupdown=1,
			i_pllena=1,
			i_scanaclr=0,
			i_scanclk=0,
			i_scanclkena=1,
			i_scandata=0,
			i_scanread=0,
			i_scanwrite=0
		)

class _CRG(Module):
	def __init__(self, platform):
		self.clock_domains.cd_sys = ClockDomain()
		self.clock_domains.cd_sys_ps = ClockDomain()
		self.clock_domains.cd_por = ClockDomain(reset_less=True)

		clk50 = platform.request("clk50")

		sys_pll = _PLL(20, "sys", 0, "NORMAL")
		self.submodules += sys_pll
		self.comb += [
			sys_pll.clk_in.eq(clk50),
			self.cd_sys.clk.eq(sys_pll.clk_out)
		]

		sdram_pll = _PLL(20, "sdram", -3000, "ZERO_DELAY_BUFFER")
		self.submodules += sdram_pll
		self.comb += [
			sdram_pll.clk_in.eq(clk50),
			self.cd_sys_ps.clk.eq(sdram_pll.clk_out)
		]

		# Power on Reset (vendor agnostic)
		rst_n = Signal()
		self.sync.por += rst_n.eq(1)
		self.comb += [
			self.cd_por.clk.eq(self.cd_sys.clk),
			self.cd_sys.rst.eq(~rst_n),
			self.cd_sys_ps.rst.eq(~rst_n)
		]

		self.comb += platform.request("sdram_clock").eq(self.cd_sys_ps.clk)

class BaseSoC(SDRAMSoC):
	default_platform = "de0nano"

	def __init__(self, platform, sdram_controller_settings=LASMIconSettings(), **kwargs):
		SDRAMSoC.__init__(self, platform,
			clk_freq=100*1000000,
			with_integrated_rom=True,
			sdram_controller_settings=sdram_controller_settings,
			**kwargs)

		self.submodules.crg = _CRG(platform)

		if not self.with_integrated_main_ram:
			sdram_module = IS42S16160(self.clk_freq)
			self.submodules.sdrphy = gensdrphy.GENSDRPHY(platform.request("sdram"))
			self.register_sdram_phy(self.sdrphy, sdram_module.geom_settings, sdram_module.timing_settings)

default_subtarget = BaseSoC