Source code for artiq.coredevice.i2c

from artiq.language.core import syscall, kernel
from artiq.language.types import TBool, TInt32, TNone
from artiq.coredevice.exceptions import I2CError


@syscall(flags={"nowrite"})
def i2c_init(busno: TInt32) -> TNone:
    raise NotImplementedError("syscall not simulated")


@syscall(flags={"nounwind", "nowrite"})
def i2c_start(busno: TInt32) -> TNone:
    raise NotImplementedError("syscall not simulated")


@syscall(flags={"nounwind", "nowrite"})
def i2c_stop(busno: TInt32) -> TNone:
    raise NotImplementedError("syscall not simulated")


@syscall(flags={"nounwind", "nowrite"})
def i2c_write(busno: TInt32, b: TInt32) -> TBool:
    raise NotImplementedError("syscall not simulated")


@syscall(flags={"nounwind", "nowrite"})
def i2c_read(busno: TInt32, ack: TBool) -> TInt32:
    raise NotImplementedError("syscall not simulated")


[docs]class PCA9548: """Driver for the PCA9548 I2C bus switch. On the KC705, this chip is used for selecting the I2C buses on the two FMC connectors. HPC=1, LPC=2. """ def __init__(self, dmgr, busno=0, address=0xe8, core_device="core"): self.core = dmgr.get(core_device) self.busno = busno self.address = address @kernel
[docs] def set(self, channel): """Select one channel. Selecting multiple channels at the same time is not supported by this driver. :param channel: channel number (0-7) """ i2c_init(self.busno) i2c_start(self.busno) try: if not i2c_write(self.busno, self.address): raise I2CError("PCA9548 failed to ack address") if not i2c_write(self.busno, 1 << channel): raise I2CError("PCA9548 failed to ack control word") finally: i2c_stop(self.busno)
@kernel def readback(self): i2c_init(self.busno) i2c_start(self.busno) r = 0 try: if not i2c_write(self.busno, self.address | 1): raise I2CError("PCA9548 failed to ack address") r = i2c_read(self.busno, False) finally: i2c_stop(self.busno) return r
[docs]class TCA6424A: """Driver for the TCA6424A I2C I/O expander. On the NIST QC2 hardware, this chip is used for switching the directions of TTL buffers.""" def __init__(self, dmgr, busno=0, address=0x44, core_device="core"): self.core = dmgr.get(core_device) self.busno = busno self.address = address @kernel def _write24(self, command, value): i2c_init(self.busno) i2c_start(self.busno) try: if not i2c_write(self.busno, self.address): raise I2CError("TCA6424A failed to ack address") if not i2c_write(self.busno, command): raise I2CError("TCA6424A failed to ack command") for i in range(3): if not i2c_write(self.busno, value >> 16): raise I2CError("TCA6424A failed to ack data") value <<= 8 finally: i2c_stop(self.busno) @kernel
[docs] def set(self, outputs): """Drive all pins of the chip to the levels given by the specified 24-bit word. On the QC2 hardware, the LSB of the word determines the direction of TTL0 (on a given FMC card) and the MSB that of TTL23. A bit set to 1 means the TTL is an output. """ outputs_le = ( ((outputs & 0xff0000) >> 16) | (outputs & 0x00ff00) | (outputs & 0x0000ff) << 16) self._write24(0x8c, 0) # set all directions to output self._write24(0x84, outputs_le) # set levels