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lpGBT readout with Adafruit FT323H and blinka

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    Authored by Branislav Ristic

    Start with a new environment and install packages

    python -m venv --system-site-packages lpgbt_env
source lpgbt_env/bin/activate
pip install -U pip
pip install Adafruit-Blinka git+https://gitlab.cern.ch/lpgbt/lpgbt_control_lib.git@v4.0.0

    You need to set the BLINKA_FT232H environmental variable for the USB-I2C adapter to be detected. I'd suggest to place it in the activate script of the environment so it gets set automatically (you have to reactivate the environment after the next step).

    cat >> lpgbt_env/bin/activate <<EOF
echo "Using FT232 for blinka"
export BLINKA_FT232H=1
EOF

    You can then access registers via

    import lpgbt
chip1 = lpgbt.get_lpgbt(0x70)

chip1.read_reg(chip1.CHIPID0)
# or
chip1.read_regs(chip1.CHIPID0, 4) # returns CHIPID0 and the following 3 registers as a list

chip1.pusm_get_state()
chip1.wait_pusm_state(chip1.pusm_state.READY, timeout=1) #timeout in seconds, throws exception if state not reached within timeout

    Interesting states

    chip1.PusmState.PAUSE_FOR_DLL_CONFIG_DONE
chip1.PusmState.READY
    Edited
    lpgbt.py 1.58 KiB
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    from functools import partial
import board
import logging

from lpgbt_control_lib import LpgbtV0, LpgbtV1

i2c = board.I2C()


def encodeReg(reg_addr):

    regl = (reg_addr & 0xFF) >> 0
    regh = (reg_addr) >> 8

    return bytes([regl, regh])


# low level access to I2C interface
def write_lpgbt_regs_i2c(chip_addr, reg_addr, reg_vals):

    outbuf = encodeReg(reg_addr) + bytes(reg_vals)
    i2c.writeto(chip_addr,  outbuf)


def read_lpgbt_regs_i2c(chip_addr, reg_addr, read_len):

    outbuf = encodeReg(reg_addr)
    inbuf = bytearray(read_len)

    i2c.writeto_then_readfrom(
            chip_addr,
            outbuf,
            inbuf )

    return list(inbuf)


def get_lpgbt(chip_addr, version=1):

    # get a logger for lpGBT library logging
    lpgbt_logger = logging.getLogger(f"lpgbt_{hex(chip_addr)}")

    # instantiate lpGBT class
    chip = [LpgbtV0,LpgbtV1][version](logger=lpgbt_logger)

    # register communications interface(s)
    chip.register_comm_intf(
        name="I2C",
        write_regs = partial(write_lpgbt_regs_i2c, chip_addr=chip_addr),
        read_regs = partial(read_lpgbt_regs_i2c, chip_addr=chip_addr),
        default=True )

    return chip


def main():
    
    chip1 = get_lpgbt(0x70)
    pusm = chip1.pusm_get_state()
    print("state", chip1)

    if (pusm == chip1.pusm_state.PAUSE_FOR_DLL_CONFIG_DONE):
        print("fake configuring DLL")
        chip1.config_done()

    while True:
        try:
            pusm=chip1.wait_pusm_state(chip1.pusm_state.READY, 1)
        except:
            pass
        print("READY")

if __name__ == "__main__":
    main()
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