Source code for pynq.lib.iic

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__author__ = "Peter Ogden"
__copyright__ = "Copyright 2018, Xilinx"
__email__ = "pynq_support@xilinx.com"

import cffi
import os
from pynq import DefaultIP

LIB_SEARCH_PATH = os.path.dirname(os.path.realpath(__file__))

_lib_header = R"""
unsigned XIic_Recv(unsigned long BaseAddress, unsigned char Address,
                   unsigned char *BufferPtr, unsigned ByteCount, unsigned char Option);

unsigned XIic_Send(unsigned long BaseAddress, unsigned char Address,
                   unsigned char *BufferPtr, unsigned ByteCount, unsigned char Option);

unsigned int XIic_CheckIsBusBusy(unsigned long BaseAddress);

unsigned int XIic_WaitBusFree(unsigned long BaseAddress);
"""

_lib_location = os.path.join(LIB_SEARCH_PATH, 'libiic.so')


[docs]class AxiIIC(DefaultIP): """Driver for the AXI IIC controller """ _lib = None _ffi = None REPEAT_START = 1 @staticmethod def _initialise_lib(): AxiIIC._ffi = cffi.FFI() AxiIIC._ffi.cdef(_lib_header) AxiIIC._lib = AxiIIC._ffi.dlopen(_lib_location) def __init__(self, description): """Create a new instance of the driver Parameters ---------- description : dict Entry in the ip_dict for the IP """ if AxiIIC._lib is None: AxiIIC._initialise_lib() super().__init__(description) self._virtaddr = self.mmio.array.ctypes.data
[docs] def send(self, address, data, length, option=0): """Send data to an attached IIC slave Parameters ---------- address : int Address of the slave device data : bytes-like Data to send length : int Length of data option : int Optionally `REPEAT_START` to keep hold of the bus between transactions """ sent = AxiIIC._lib.XIic_Send( self._virtaddr, address, data, length, option) if sent == 0: raise RuntimeError("Could not send I2C data") return sent
[docs] def receive(self, address, data, length, option=0): """Receive data from an attached IIC slave Parameters ---------- address : int Address of the slave device data : bytes-like Data to receive length : int Number of bytes to receive option : int Optionally `REPEAT_START` to keep hold of the bus between transactions """ received = AxiIIC._lib.XIic_Recv( self._virtaddr, address, data, length, option) if received == 0: raise RuntimeError("Could not receive I2C data") return received
[docs] def wait(self): """Wait for the transaction to complete """ timed_out = AxiIIC._lib.XIic_WaitBusFree(self._virtaddr) if timed_out: raise RuntimeError("Timed out waiting for free bus")
bindto = ['xilinx.com:ip:axi_iic:2.0']