Add PLL for ECP5 device

Means we can synthesize at 40Mhz (where we currently make timing) and
our UART still works at 115200 baud.

Tested working hello world unmodified with ECP5 eval board. Orange
Crab is updated but is untested.

Signed-off-by: Michael Neuling <mikey@neuling.org>
pull/223/head
Michael Neuling 4 years ago
parent 4e977bf8a9
commit 5aaa63ee3b

@ -149,10 +149,10 @@ FPGA_TARGET ?= ORANGE-CRAB
ifeq ($(FPGA_TARGET), ORANGE-CRAB)
RESET_LOW=true
CLK_INPUT=50000000
CLK_FREQUENCY=50000000
CLK_FREQUENCY=40000000
LPF=constraints/orange-crab.lpf
PACKAGE=CSFBGA285
NEXTPNR_FLAGS=--um5g-85k --freq 50
NEXTPNR_FLAGS=--um5g-85k --freq 40
OPENOCD_JTAG_CONFIG=openocd/olimex-arm-usb-tiny-h.cfg
OPENOCD_DEVICE_CONFIG=openocd/LFE5UM5G-85F.cfg
endif
@ -161,10 +161,10 @@ endif
ifeq ($(FPGA_TARGET), ECP5-EVN)
RESET_LOW=true
CLK_INPUT=12000000
CLK_FREQUENCY=12000000
CLK_FREQUENCY=40000000
LPF=constraints/ecp5-evn.lpf
PACKAGE=CABGA381
NEXTPNR_FLAGS=--um5g-85k --freq 12
NEXTPNR_FLAGS=--um5g-85k --freq 40
OPENOCD_JTAG_CONFIG=openocd/ecp5-evn.cfg
OPENOCD_DEVICE_CONFIG=openocd/LFE5UM5G-85F.cfg
endif
@ -172,7 +172,7 @@ endif
GHDL_IMAGE_GENERICS=-gMEMORY_SIZE=$(MEMORY_SIZE) -gRAM_INIT_FILE=$(RAM_INIT_FILE) \
-gRESET_LOW=$(RESET_LOW) -gCLK_INPUT=$(CLK_INPUT) -gCLK_FREQUENCY=$(CLK_FREQUENCY)

clkgen=fpga/clk_gen_bypass.vhd
clkgen=fpga/clk_gen_ecp5.vhd
toplevel=fpga/top-generic.vhdl
dmi_dtm=dmi_dtm_dummy.vhdl


@ -0,0 +1,127 @@
library ieee;
use ieee.std_logic_1164.all;

entity clock_generator is
generic (
CLK_INPUT_HZ : positive := 12000000;
CLK_OUTPUT_HZ : positive := 50000000
);

port (
ext_clk : in std_logic;
pll_rst_in : in std_logic;
pll_clk_out : out std_logic;
pll_locked_out : out std_logic
);

end entity clock_generator;

architecture bypass of clock_generator is

-- prototype of ECP5 PLL
component EHXPLLL is
generic (
CLKI_DIV : integer := 1;
CLKFB_DIV : integer := 1;
CLKOP_DIV : integer := 8;
CLKOS_DIV : integer := 8;
CLKOS2_DIV : integer := 8;
CLKOS3_DIV : integer := 8;
CLKOP_ENABLE : string := "ENABLED";
CLKOS_ENABLE : string := "DISABLED";
CLKOS2_ENABLE : string := "DISABLED";
CLKOS3_ENABLE : string := "DISABLED";
CLKOP_CPHASE : integer := 0;
CLKOS_CPHASE : integer := 0;
CLKOS2_CPHASE : integer := 0;
CLKOS3_CPHASE : integer := 0;
CLKOP_FPHASE : integer := 0;
CLKOS_FPHASE : integer := 0;
CLKOS2_FPHASE : integer := 0;
CLKOS3_FPHASE : integer := 0;
FEEDBK_PATH : string := "CLKOP";
CLKOP_TRIM_POL : string := "RISING";
CLKOP_TRIM_DELAY : integer := 0;
CLKOS_TRIM_POL : string := "RISING";
CLKOS_TRIM_DELAY : integer := 0;
OUTDIVIDER_MUXA : string := "DIVA";
OUTDIVIDER_MUXB : string := "DIVB";
OUTDIVIDER_MUXC : string := "DIVC";
OUTDIVIDER_MUXD : string := "DIVD";
PLL_LOCK_MODE : integer := 0;
PLL_LOCK_DELAY : integer := 200;
STDBY_ENABLE : string := "DISABLED";
REFIN_RESET : string := "DISABLED";
SYNC_ENABLE : string := "DISABLED";
INT_LOCK_STICKY : string := "ENABLED";
DPHASE_SOURCE : string := "DISABLED";
PLLRST_ENA : string := "DISABLED";
INTFB_WAKE : string := "DISABLED" );
port (
CLKI : in std_logic;
CLKFB : in std_logic;
PHASESEL1 : in std_logic;
PHASESEL0 : in std_logic;
PHASEDIR : in std_logic;
PHASESTEP : in std_logic;
PHASELOADREG : in std_logic;
STDBY : in std_logic;
PLLWAKESYNC : in std_logic;
RST : in std_logic;
ENCLKOP : in std_logic;
ENCLKOS : in std_logic;
ENCLKOS2 : in std_logic;
ENCLKOS3 : in std_logic;
CLKOP : out std_logic;
CLKOS : out std_logic;
CLKOS2 : out std_logic;
CLKOS3 : out std_logic;
LOCK : out std_logic;
INTLOCK : out std_logic;
REFCLK : out std_logic;
CLKINTFB : out std_logic );
end component;

signal clkop : std_logic;
signal lock : std_logic;

-- PLL constants based on prjtrellis example
constant PLL_IN : natural := 2000000;
constant PLL_OUT : natural := 600000000;

-- Configration for ECP5 PLL
constant PLL_CLKOP_DIV : natural := PLL_OUT/CLK_OUTPUT_HZ;
constant PLL_CLKFB_DIV : natural := CLK_OUTPUT_HZ/PLL_IN;
constant PLL_CLKI_DIV : natural := CLK_INPUT_HZ/PLL_IN;

begin
pll_clk_out <= clkop;
pll_locked_out <= not lock; -- FIXME: EHXPLLL lock signal active low?!?

clkgen: EHXPLLL
generic map(
CLKOP_CPHASE => 11, -- FIXME: Copied from prjtrells.
CLKOP_DIV => PLL_CLKOP_DIV,
CLKFB_DIV => PLL_CLKFB_DIV,
CLKI_DIV => PLL_CLKI_DIV
)
port map (
CLKI => ext_clk,
CLKOP => clkop,
CLKFB => clkop,
LOCK => lock,
RST => pll_rst_in,
PHASESEL1 => '0',
PHASESEL0 => '0',
PHASEDIR => '0',
PHASESTEP => '0',
PHASELOADREG => '0',
STDBY => '0',
PLLWAKESYNC => '0',
ENCLKOP => '0',
ENCLKOS => '0',
ENCLKOS2 => '0',
ENCLKOS3 => '0'
);

end architecture bypass;
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