Anyone have code for Si570 Synth chip

I recently purchased a few Silicon Labs Si570 Programmable Oscillators / Frequency Synthesizer ICs. There are a few old posts on this Forum for this chip, but was wondering if anyone had done any recent code snippets / apps, that they are willing to share, for using this IC. If there are none out there I will work thru the math and post the results. Thanks ahead of time.

Comments

  • Ozprop made a si5351 driver for the prop, perhaps that can help?
  • jmgjmg Posts: 13,463
    I did notice this post on SiLabs forums.. which may help too.
    https://www.silabs.com/community/timing/forum.topic.html/si570_does_not_compl-wBcL

    Apparently, the Si570 registers move about, depending on the ppm of the part. Most would not expect that :)

    A : 50 ppm temperature stability, 61.5 ppm total stability => Configuration Registers 7-12
    B : 20 ppm temperature stability, 31.5 ppm total stability => Configuration Registers 7-12
    C : 7 ppm temperature stability, 20 ppm total stability => Configuration Registers 13-18"
  • jmg wrote: »
    I did notice this post on SiLabs forums.. which may help too.
    https://www.silabs.com/community/timing/forum.topic.html/si570_does_not_compl-wBcL

    Apparently, the Si570 registers move about, depending on the ppm of the part. Most would not expect that :)

    A : 50 ppm temperature stability, 61.5 ppm total stability => Configuration Registers 7-12
    B : 20 ppm temperature stability, 31.5 ppm total stability => Configuration Registers 7-12
    C : 7 ppm temperature stability, 20 ppm total stability => Configuration Registers 13-18"
    Urgh! What a trap.
    My Prop boards: P8XBlade2, RamBlade, CpuBlade, TriBlade
    Prop OS (also see Sphinx, PropDos, PropCmd, Spinix)
    Website: www.clusos.com
    Prop Tools (Index) , Emulators (Index) , ZiCog (Z80)
  • jmgjmg Posts: 13,463
    Tubular wrote: »
    Ozprop made a si5351 driver for the prop, perhaps that can help?

    That code is here I think
    https://forums.parallax.com/discussion/163409/silabs-si5351-clock-generator-spin-driver

    They are broadly similar, just different register sizes/location, but they all have Xtal Divider / VCO divider etc and so
    Si5351 code should be better than starting from scratch.

  • PropGuy2PropGuy2 Posts: 201
    edited 2019-05-08 - 15:10:08
    Thanks for the reference - The main problem is that there is so much misinformation, and bad code stuff written out there and published on the different forums (not Parallax, of course) by people who have not even read the Datasheets. They just copy & past the same bad code over and over, without checking their logic and math. On the other side, part of my problem has been that the Prop chip does not have signed and unsigned LONGS, as it does for Bytes and Words. I need 64 bit math to do the calculations correctly.
  • @PropGuy2

    Do you mind sharing your solution for 64-bit math? It could prove valuable to others.

    Cheers,
    Jesse
    --
    WIP Spin drivers for various devices: LSM9DS1 IMU (SPI) | Newhaven 4x20 OLED (I2C) | MLX90621 (I2C) | SHT3x (I2C) | SSD1306 OLED (I2C; P1-SPIN, P2-SPIN2) | TCS3x7x (I2C) | MAX31856 (SPI) | BMP280 (I2C) | TMC2130 (SPI) | nRF24L01+ (SPI) | MLX90614 (I2C) | MAX9744 (I2C) | DS28CM00 (I2C) | TSL2591 (I2C) | CC1101 (SPI) | SX1231 (SPI)
Sign In or Register to comment.