minitests/litex/uart_ddr/arty/scripts/sdram_init.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
#
# Copyright (C) 2017-2020  The Project X-Ray Authors.
#
# Use of this source code is governed by a ISC-style
# license that can be found in the LICENSE file or at
# https://opensource.org/licenses/ISC
#
# SPDX-License-Identifier: ISC
dfii_control_sel = 0x01
dfii_control_cke = 0x02
dfii_control_odt = 0x04
dfii_control_reset_n = 0x08

dfii_command_cs = 0x01
dfii_command_we = 0x02
dfii_command_cas = 0x04
dfii_command_ras = 0x08
dfii_command_wrdata = 0x10
dfii_command_rddata = 0x20

ddrx_mr1 = 0x6

init_sequence = [
    ("Release reset", 0, 0, dfii_control_odt | dfii_control_reset_n, 50000),
    (
        "Bring CKE high", 0, 0,
        dfii_control_cke | dfii_control_odt | dfii_control_reset_n, 10000),
    (
        "Load Mode Register 2, CWL=5", 512, 2, dfii_command_ras
        | dfii_command_cas | dfii_command_we | dfii_command_cs, 0),
    (
        "Load Mode Register 3", 0, 3, dfii_command_ras | dfii_command_cas
        | dfii_command_we | dfii_command_cs, 0),
    (
        "Load Mode Register 1", 6, 1, dfii_command_ras | dfii_command_cas
        | dfii_command_we | dfii_command_cs, 0),
    (
        "Load Mode Register 0, CL=6, BL=8", 2336, 0, dfii_command_ras
        | dfii_command_cas | dfii_command_we | dfii_command_cs, 200),
    ("ZQ Calibration", 1024, 0, dfii_command_we | dfii_command_cs, 200),
]