Source code for pynq.lib.arduino.arduino_grove_adc

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import struct
from math import ceil
from . import Arduino
from . import ARDUINO_GROVE_I2C
from . import MAILBOX_OFFSET


__author__ = "Cathal McCabe"
__copyright__ = "Copyright 2016, Xilinx"
__email__ = "pynq_support@xilinx.com"


ARDUINO_GROVE_ADC_PROGRAM = "arduino_grove_adc.bin"
GROVE_ADC_LOG_START = MAILBOX_OFFSET+16
GROVE_ADC_LOG_END = GROVE_ADC_LOG_START+(1000*4)
CONFIG_IOP_SWITCH = 0x1
READ_RAW_DATA = 0x2
READ_VOLTAGE = 0x3
READ_AND_LOG_RAW_DATA = 0x4
READ_AND_LOG_VOLTAGE = 0x5
SET_LOW_LEVEL = 0x6
SET_HIGH_LEVEL = 0x7
SET_HYSTERESIS_LEVEL = 0x8
READ_LOWEST_LEVEL = 0x9
READ_HIGHEST_LEVEL = 0xA
READ_STATUS = 0xB
RESET_ADC = 0xC


def _reg2float(reg):
    """Converts 32-bit register value to floats in Python.

    Parameters
    ----------
    reg: int
        A 32-bit register value read from the mailbox.

    Returns
    -------
    float
        A float number translated from the register value.

    """
    s = struct.pack('>l', reg)
    return struct.unpack('>f', s)[0]


[docs]class Grove_ADC(object): """This class controls the Grove IIC ADC. Grove ADC is a 12-bit precision ADC module based on ADC121C021. Hardware version: v1.2. Attributes ---------- microblaze : Arduino Microblaze processor instance used by this module. log_running : int The state of the log (0: stopped, 1: started). log_interval_ms : int Time in milliseconds between sampled reads. """ def __init__(self, mb_info, gr_pin): """Return a new instance of an Grove_ADC object. Note ---- The parameter `gr_pin` is a list organized as [scl_pin, sda_pin]. Parameters ---------- mb_info : dict A dictionary storing Microblaze information, such as the IP name and the reset name. gr_pin: list A group of pins on arduino-grove shield. """ if gr_pin not in [ARDUINO_GROVE_I2C]: raise ValueError("Group number can only be I2C.") self.microblaze = Arduino(mb_info, ARDUINO_GROVE_ADC_PROGRAM) self.log_interval_ms = 1000 self.log_running = 0 self.microblaze.write_blocking_command(CONFIG_IOP_SWITCH)
[docs] def read_raw(self): """Read the ADC raw value from the Grove ADC peripheral. Returns ------- int The raw value from the sensor. """ self.microblaze.write_blocking_command(READ_RAW_DATA) value = self.microblaze.read_mailbox(0) return value
[docs] def read(self): """Read the ADC voltage from the Grove ADC peripheral. Returns ------- float The float value after translation. """ self.microblaze.write_blocking_command(READ_VOLTAGE) value = self.microblaze.read_mailbox(0) return _reg2float(value)
[docs] def set_log_interval_ms(self, log_interval_ms): """Set the length of the log for the Grove ADC peripheral. This method can set the time interval between two samples, so that users can read out multiple values in a single log. Parameters ---------- log_interval_ms : int The time between two samples in milliseconds, for logging only. Returns ------- None """ if log_interval_ms < 0: raise ValueError("Time between samples should be no less than 0.") self.log_interval_ms = log_interval_ms self.microblaze.write_mailbox(4, log_interval_ms)
[docs] def start_log_raw(self): """Start recording raw data in a log. This method will first call set_log_interval_ms() before sending the command. Returns ------- None """ self.log_running = 1 self.set_log_interval_ms(self.log_interval_ms) self.microblaze.write_non_blocking_command(READ_AND_LOG_RAW_DATA)
[docs] def start_log(self): """Start recording multiple voltage values (float) in a log. This method will first call set_log_interval_ms() before sending the command. Returns ------- None """ self.log_running = 1 self.set_log_interval_ms(self.log_interval_ms) self.microblaze.write_non_blocking_command(READ_AND_LOG_VOLTAGE)
[docs] def stop_log_raw(self): """Stop recording the raw values in the log. Simply send the command 0xC to stop the log. Returns ------- None """ if self.log_running == 1: self.microblaze.write_non_blocking_command(RESET_ADC) self.log_running = 0 else: raise RuntimeError("No grove ADC log running.")
[docs] def stop_log(self): """Stop recording the voltage values in the log. Simply send the command 0xC to stop the log. Returns ------- None """ if self.log_running == 1: self.microblaze.write_non_blocking_command(RESET_ADC) self.log_running = 0 else: raise RuntimeError("No grove ADC log running.")
[docs] def get_log_raw(self): """Return list of logged raw samples. Returns ------- list List of valid raw samples from the ADC sensor. """ # Stop logging self.stop_log() # Prep iterators and results list [head_ptr, tail_ptr] = self.microblaze.read_mailbox(0x8, 2) readings = list() # Sweep circular buffer for samples if head_ptr == tail_ptr: return None elif head_ptr < tail_ptr: num_words = int(ceil((tail_ptr - head_ptr) / 4)) data = self.microblaze.read(head_ptr, num_words) readings += data else: num_words = int(ceil((PMOD_ALS_LOG_END - head_ptr) / 4)) data = self.microblaze.read(head_ptr, num_words) readings += data num_words = int(ceil((tail_ptr - PMOD_ALS_LOG_START) / 4)) data = self.microblaze.read(PMOD_ALS_LOG_START, num_words) readings += data return readings
[docs] def get_log(self): """Return list of logged samples. Returns ------- list List of valid voltage samples (floats) from the ADC sensor. """ # Stop logging self.stop_log() # Prep iterators and results list [head_ptr, tail_ptr] = self.microblaze.read_mailbox(0x8, 2) readings = list() # Sweep circular buffer for samples if head_ptr == tail_ptr: return None elif head_ptr < tail_ptr: num_words = int(ceil((tail_ptr - head_ptr) / 4)) data = self.microblaze.read(head_ptr, num_words) readings += [float("{0:.4f}".format(_reg2float(i))) for i in data] else: num_words = int(ceil((GROVE_ADC_LOG_END - head_ptr) / 4)) data = self.microblaze.read(head_ptr, num_words) readings += [float("{0:.4f}".format(_reg2float(i))) for i in data] num_words = int(ceil((tail_ptr - GROVE_ADC_LOG_START) / 4)) data = self.microblaze.read(GROVE_ADC_LOG_START, num_words) readings += [float("{0:.4f}".format(_reg2float(i))) for i in data] return readings
[docs] def reset(self): """Resets/initializes the ADC. Returns ------- None """ self.microblaze.write_blocking_command(RESET_ADC)