diff options
Diffstat (limited to 'mpm/python/usrp_mpm/periph_manager/x4xx_clk_aux.py')
| -rw-r--r-- | mpm/python/usrp_mpm/periph_manager/x4xx_clk_aux.py | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/mpm/python/usrp_mpm/periph_manager/x4xx_clk_aux.py b/mpm/python/usrp_mpm/periph_manager/x4xx_clk_aux.py index fcd655d9d..f8dc83a06 100644 --- a/mpm/python/usrp_mpm/periph_manager/x4xx_clk_aux.py +++ b/mpm/python/usrp_mpm/periph_manager/x4xx_clk_aux.py @@ -17,7 +17,13 @@ from usrp_mpm.sys_utils.udev import get_eeprom_paths_by_symbol from usrp_mpm.sys_utils import i2c_dev from usrp_mpm.chips import LMK05318 -X400_CLKAUX_DEFAULT_TUNING_WORD = 0x200 # 1.65V which would be a DAC value of 512 +# DAC AD5338R provides V_out = V_ref * gain (tune_word / 2^N) +# We have gain pin enabled (2) and N = 10 for the AD5338 models +# to provide 1.65V to the OCXO we need: +# tune_word = 1.65V / (2.5V * 2) * 2^10 +# Note: V_vdd = 3.3V so V_out will saturate at 3.3V (it won't reach 5V) +# the tuning word is therefore limited to 0x2A4 +X400_CLKAUX_DEFAULT_TUNING_WORD = 0x152 X400_CLKAUX_DEFAULT_REVISION = 0x1 X400_CLKAUX_I2C_LABEL = 'clkaux_i2c' X400_CLKAUX_SPI_LABEL = 'clkaux_spi' |