# Copyright (c) 2018, Xilinx, Inc.
# SPDX-License-Identifier: BSD-3-Clause
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:2.1']