Source code for pynq.lib.pmod.pmod_dpot

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from . import Pmod


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


PMOD_DPOT_PROGRAM = "pmod_dpot.bin"
CANCEL = 0x1
SET_POT_SIMPLE = 0x3
SET_POT_RAMP = 0x5


[docs]class Pmod_DPOT(object): """This class controls a digital potentiometer Pmod. The Pmod DPOT (PB 200-239) is a digital potentiometer powered by the AD5160. Users may set a desired resistance between 60 ~ 10k ohms. Attributes ---------- microblaze : Pmod Microblaze processor instance used by this module. """ def __init__(self, mb_info): """Return a new instance of a DPOT object. Parameters ---------- mb_info : dict A dictionary storing Microblaze information, such as the IP name and the reset name. """ self.microblaze = Pmod(mb_info, PMOD_DPOT_PROGRAM)
[docs] def write(self, val, step=0, log_ms=0): """Write the value into the DPOT. This method will write the parameters "value", "step", and "log_ms" all together into the DPOT Pmod. The parameter "log_ms" is only used for debug; users can ignore this parameter. Parameters ---------- val : int The initial value to start, in [0, 255]. step : int The number of steps when ramping up to the final value. log_ms : int The length of the log in milliseconds, for debug only. Returns ------- None """ if not 0 <= val <= 255: raise ValueError("Initial value should be in range [0, 255].") if not 0 <= step <= (255-val): raise ValueError("Ramp steps should be in range [0, {}]." .format(255-val)) if log_ms < 0: raise ValueError("Requested log_ms value cannot be less than 0.") self.microblaze.write_non_blocking_command(CANCEL) self.microblaze.write_mailbox(0, [val, step, log_ms]) if step == 0: self.microblaze.write_non_blocking_command(SET_POT_SIMPLE) else: self.microblaze.write_non_blocking_command(SET_POT_RAMP)