AD9553 no-OS Driver

See drivers/frequency/ad9553 (doxygen) for the Doxygen documentation.

Supported Devices

Overview

The AD9553 is a PLL-based clock translator designed for passive optical networks (PON) and base stations. It employs an integer-N PLL for specific frequency translation, allowing up to two single-ended or one differential input via the REFA and REFB inputs. The device supports holdover applications with a 25 MHz crystal attached to the XTAL input. It is pin programmable, offering frequency translations from 15 input frequencies to 52 output frequency pairs (OUT1 and OUT2). The AD9553 includes a 3-wire SPI for custom frequency translations and supports LVPECL, LVDS, or CMOS logic levels. It operates within an industrial temperature range of -40 degrees C to +85 degrees C.

Applications

  • Cost effective replacement of high frequency VCXO, OCXO, and SAW resonators

  • Flexible frequency translation for SONET/SDH, Ethernet, Fiber Channel, DRFI/DOCSIS, and PON/EPON/GPON

  • Wireless infrastructure

  • Test and measurement

AD9553 Device Configuration

Driver Initialization

In order to be able to use the device, you will have to provide the support for the communication protocol (SPI).

The first API to be called is ad9553_setup. Make sure that it returns 0, which means that the driver was initialized correctly. This function resets the device, configures the PLL charge pump control, activates the lock detector, and sets the division values for frequency translation through SPI transactions.

SPI Communication

ad9553_reg_read and ad9553_reg_write manage SPI protocol transactions for reading and writing to the AD9553 registers. ad9553_reg_read retrieves data from specific registers, while ad9553_reg_write configures registers by sending data. The SPI protocol uses a 3-byte transaction format where the MSB of byte 0 indicates a read/write operation.

Resource Management

ad9553_remove handles resource deallocation by removing SPI descriptors used by the AD9553 driver, ensuring efficient use of system resources and preventing memory leaks.

AD9553 Driver Initialization Example

struct ad9553_dev *ad9553_device;
struct no_os_spi_init_param ad9553_spi_ip = {
        .device_id = SPI_DEVICE_ID,
        .max_speed_hz = 2000000u,
        .chip_select = SPI_CS,
        .mode = NO_OS_SPI_MODE_0,
        .platform_ops = SPI_OPS,
        .extra = SPI_EXTRA,
};
struct ad9553_init_param ad9553_ip = {
        .spi_init = ad9553_spi_ip,
};

ret = ad9553_setup(&ad9553_device, &ad9553_ip);
if (ret)
        goto error;