mirror of https://github.com/m-labs/artiq.git
126 lines
3.8 KiB
Python
126 lines
3.8 KiB
Python
"""
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Non-realtime drivers for I2C chips on the core device.
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"""
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from artiq.language.core import syscall, kernel
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from artiq.language.types import TBool, TInt32, TNone
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from artiq.coredevice.exceptions import I2CError
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@syscall(flags={"nounwind", "nowrite"})
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def i2c_start(busno: TInt32) -> TNone:
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raise NotImplementedError("syscall not simulated")
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@syscall(flags={"nounwind", "nowrite"})
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def i2c_restart(busno: TInt32) -> TNone:
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raise NotImplementedError("syscall not simulated")
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@syscall(flags={"nounwind", "nowrite"})
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def i2c_stop(busno: TInt32) -> TNone:
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raise NotImplementedError("syscall not simulated")
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@syscall(flags={"nounwind", "nowrite"})
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def i2c_write(busno: TInt32, b: TInt32) -> TBool:
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raise NotImplementedError("syscall not simulated")
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@syscall(flags={"nounwind", "nowrite"})
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def i2c_read(busno: TInt32, ack: TBool) -> TInt32:
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raise NotImplementedError("syscall not simulated")
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class PCA9548:
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"""Driver for the PCA9548 I2C bus switch.
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I2C transactions not real-time, and are performed by the CPU without
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involving RTIO.
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On the KC705, this chip is used for selecting the I2C buses on the two FMC
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connectors. HPC=1, LPC=2.
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"""
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def __init__(self, dmgr, busno=0, address=0xe8, core_device="core"):
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self.core = dmgr.get(core_device)
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self.busno = busno
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self.address = address
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@kernel
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def set(self, channel):
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"""Select one channel.
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Selecting multiple channels at the same time is not supported by this
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driver.
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:param channel: channel number (0-7)
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"""
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i2c_start(self.busno)
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try:
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if not i2c_write(self.busno, self.address):
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raise I2CError("PCA9548 failed to ack address")
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if not i2c_write(self.busno, 1 << channel):
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raise I2CError("PCA9548 failed to ack control word")
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finally:
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i2c_stop(self.busno)
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@kernel
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def readback(self):
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i2c_start(self.busno)
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r = 0
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try:
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if not i2c_write(self.busno, self.address | 1):
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raise I2CError("PCA9548 failed to ack address")
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r = i2c_read(self.busno, False)
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finally:
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i2c_stop(self.busno)
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return r
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class TCA6424A:
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"""Driver for the TCA6424A I2C I/O expander.
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I2C transactions not real-time, and are performed by the CPU without
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involving RTIO.
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On the NIST QC2 hardware, this chip is used for switching the directions
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of TTL buffers."""
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def __init__(self, dmgr, busno=0, address=0x44, core_device="core"):
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self.core = dmgr.get(core_device)
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self.busno = busno
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self.address = address
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@kernel
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def _write24(self, command, value):
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i2c_start(self.busno)
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try:
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if not i2c_write(self.busno, self.address):
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raise I2CError("TCA6424A failed to ack address")
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if not i2c_write(self.busno, command):
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raise I2CError("TCA6424A failed to ack command")
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for i in range(3):
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if not i2c_write(self.busno, value >> 16):
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raise I2CError("TCA6424A failed to ack data")
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value <<= 8
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finally:
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i2c_stop(self.busno)
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@kernel
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def set(self, outputs):
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"""Drive all pins of the chip to the levels given by the
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specified 24-bit word.
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On the QC2 hardware, the LSB of the word determines the direction of
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TTL0 (on a given FMC card) and the MSB that of TTL23.
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A bit set to 1 means the TTL is an output.
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"""
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outputs_le = (
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((outputs & 0xff0000) >> 16) |
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(outputs & 0x00ff00) |
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(outputs & 0x0000ff) << 16)
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self._write24(0x8c, 0) # set all directions to output
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self._write24(0x84, outputs_le) # set levels
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