nix-servo/fast-servo/pyfastservo/adc.py

224 lines
7.6 KiB
Python

# This file is part of Fast Servo Software Package.
#
# Copyright (C) 2023 Jakub Matyas
# Warsaw University of Technology <jakubk.m@gmail.com>
# SPDX-License-Identifier: GPL-3.0-or-later
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <https://www.gnu.org/licenses/>.
import time
import spidev
from pyfastservo.common import (
ADC_AFE_CTRL_ADDR,
ADC_BITSLIP_ADDR,
ADC_CH0_HIGH_ADDR,
ADC_CH0_LOW_ADDR,
ADC_CH1_HIGH_ADDR,
ADC_CH1_LOW_ADDR,
ADC_DELAY_ADDR,
ADC_FRAME_ADDR,
AUX_ADC_ADDR,
MAP_MASK,
PAGESIZE,
write_to_memory,
read_from_memory
)
# /dev/spidev1.0 <=> spidev<BUS>.<DEVICE>
MAIN_ADC_BUS = 1
MAIN_ADC_DEVICE = 1
AUX_ADC_BUS = 1
AUX_ADC_PORT_A = 2
AUX_ADC_PORT_B = 3
def spi_write(spi, address, value):
spi.xfer2([address, value])
def spi_read(spi, address):
rx_buffer = spi.xfer2([0x80 | address, 0x00])
return rx_buffer[1]
def main_adc_config(spi, test_pattern):
high_word = (test_pattern & 0xFF00) >> 8
low_word = test_pattern & 0xFF
spi_write(spi, 0x00, 0x80) # reset
spi_write(spi, 0x01, 0x20) # REGISTER A1: set to Two's complement Data Format
spi_write(spi, 0x02, 0x15) # REGISTER A2: set to LVDS output, set 4 data lanes and turn on test mode
spi_write(spi, 0x03, high_word) # REGISTER A3: test pattern high word
spi_write(spi, 0x04, low_word) # REGISTER A4: test pattern low word
def main_adc_test_mode(spi, enable):
reg_contents = 0x15 if enable else 0x11 # set to LVDS output, set 4 data lanes and turn on or off test mode
spi_write(spi, 0x02, reg_contents)
def verify_adc_registers(spi, reg_to_check):
for register, expected_value in reg_to_check.items():
value = spi_read(spi, register)
print(f"Spi readback register 0x{register:02x}: 0x{value:02x}")
if value != expected_value:
print(f"Different value read than sent in reg 0x{register:02x}")
def read_frame():
return read_from_memory(ADC_FRAME_ADDR, 1)[0]
def perform_bitslip():
for i in range(4):
current_frame = read_frame()
if current_frame & 0x0F != 0x0C:
print(f"Performing bitslip (iteration: {i}). Current frame: 0x{current_frame:02x}")
write_to_memory(ADC_BITSLIP_ADDR, 1)
else:
print(f"No bitslip required; Current frame: 0x{current_frame:02x}")
return
def mmcm_rst():
curr_cfg = read_from_memory(ADC_AFE_CTRL_ADDR, 1)[0] & 0x0F
write_to_memory(ADC_AFE_CTRL_ADDR, 0x10 | curr_cfg) # Reset MMCM
write_to_memory(ADC_AFE_CTRL_ADDR, 0x00 | curr_cfg) # Release MMCM Reset
while not(read_frame() & 0x10):
print(f"Waiting for MMCM to lock")
time.sleep(0.001)
def inc_ddr_clk_phase():
curr_cfg = read_from_memory(ADC_AFE_CTRL_ADDR, 1)[0] & 0x1F
write_to_memory(ADC_AFE_CTRL_ADDR, 0x40 | curr_cfg) # Set MMCM Phase Shift to be INC
write_to_memory(ADC_AFE_CTRL_ADDR, 0x60 | curr_cfg) # Assert MMCM Phase Shift EN High
write_to_memory(ADC_AFE_CTRL_ADDR, curr_cfg) # Deassert MMCM Phase Shift EN High
def dec_ddr_clk_phase():
curr_cfg = read_from_memory(ADC_AFE_CTRL_ADDR, 1)[0] & 0x1F
write_to_memory(ADC_AFE_CTRL_ADDR, 0x00 | curr_cfg) # Set MMCM Phase Shift to be DEC
write_to_memory(ADC_AFE_CTRL_ADDR, 0x20 | curr_cfg) # Assert MMCM Phase Shift EN High
write_to_memory(ADC_AFE_CTRL_ADDR, curr_cfg) # Deassert MMCM Phase Shift EN High
def find_edge():
prev_frame = read_frame()
for tap_delay in range(32):
write_to_memory(ADC_DELAY_ADDR, tap_delay)
current_frame = read_frame()
print(f"Tap delay: {tap_delay}, Current frame: 0x{current_frame:02x}")
print(f"prev_frame: 0x{prev_frame:02x}")
if current_frame != prev_frame:
final_delay = ((tap_delay+1) // 2) + 2
print(f"Edge detected; setting iDelay to: {final_delay}")
write_to_memory(ADC_DELAY_ADDR, final_delay)
return
prev_frame = current_frame
# If no edge detected
final_delay = 11
print(f"No edge detected; setting iDelay to: {final_delay}")
write_to_memory(ADC_DELAY_ADDR, final_delay)
def read_adc_channel(high_addr, low_addr):
return (read_from_memory(high_addr, 1)[0] << 8) | read_from_memory(low_addr, 1)[0]
def print_adc_channels():
adc_ch0 = read_adc_channel(ADC_CH0_HIGH_ADDR, ADC_CH0_LOW_ADDR)
adc_ch1 = read_adc_channel(ADC_CH1_HIGH_ADDR, ADC_CH1_LOW_ADDR)
print(f"Final ADC_CH0: 0x{adc_ch0:04x}")
print(f"Final ADC_CH1: 0x{adc_ch1:04x}")
def enable_adc_afe(ch1_x10=False, ch2_x10=False):
ctrl_value = (ch2_x10 << 1) | ch1_x10
write_to_memory(ADC_AFE_CTRL_ADDR, ctrl_value)
afe_ctrl = read_from_memory(ADC_AFE_CTRL_ADDR, 1)[0]
print(f"ADC_AFE_CTRL: 0x{afe_ctrl:02X}")
return afe_ctrl
def search_edge():
for tap_delay in range(32):
print(f"iDelay to: {tap_delay}")
write_to_memory(ADC_DELAY_ADDR, tap_delay)
time.sleep(1)
current_frame = read_frame()
print(f"Tap delay: {tap_delay}, Current frame: 0x{current_frame:02x}")
print_adc_channels()
def print_adc_channel(ch):
if ch == 0:
adc_ch0 = read_adc_channel(ADC_CH0_HIGH_ADDR, ADC_CH0_LOW_ADDR)
print(f"Final ADC_CH0: 0x{adc_ch0:04x}")
if ch == 1:
adc_ch1 = read_adc_channel(ADC_CH1_HIGH_ADDR, ADC_CH1_LOW_ADDR)
print(f"Final ADC_CH1: 0x{adc_ch1:04x}")
def find_min_max_ch(ch):
test = []
for i in range(100):
if ch == 0:
test.append(read_adc_channel(ADC_CH0_HIGH_ADDR, ADC_CH0_LOW_ADDR))
else:
test.append(read_adc_channel(ADC_CH1_HIGH_ADDR, ADC_CH1_LOW_ADDR))
print("ch", ch, hex(test[-1]))
print("Min:", hex(min(test)))
print("Max:", hex(max(test)))
print("Diff:", hex(max(test)-min(test)))
def configure_ltc2195():
spi = spidev.SpiDev()
try:
spi.open(MAIN_ADC_BUS, MAIN_ADC_DEVICE)
spi.max_speed_hz = 50000
spi.mode = 0b00 # CPOL = 0 CPHA = 0
spi.cshigh = False
test_pattern = 0x811F
main_adc_config(spi, test_pattern)
verify_adc_registers(spi, {
0x01: 0x20,
0x02: 0x15,
0x03: (test_pattern & 0xFF00) >> 8,
0x04: test_pattern & 0xFF
})
# ADC software reset put its PLL to sleep momentarily. Thus, MMCM needs to be reset as well.
mmcm_rst()
# Performing Word Align
perform_bitslip()
find_edge()
# Printing it once is not enough to check whether the alignment is correct.
for i in range(100):
print_adc_channels()
main_adc_test_mode(spi, False)
verify_adc_registers(spi, {0x02: 0x11}) # Verify test mode is off
# FIXME: AFE Gain 1x is not functional on that batch of fast servo under development
enable_adc_afe(ch1_x10=1, ch2_x10=1)
#find_min_max_ch(0)
#find_min_max_ch(1)
#for i in range(10):
# print_adc_channel(0)
#for i in range(10):
# print_adc_channel(1)
finally:
spi.close()
if __name__ == "__main__":
configure_ltc2195()