AD9523 no-OS driver
Supported Devices
Overview
The AD9523 is a multi-output clock distribution device with a low jitter phase-locked loop (PLL) and a voltage-controlled oscillator (VCO) that operates between 3.6 GHz and 4.0 GHz. It is optimized for LTE and multicarrier GSM base stations, using an external voltage-controlled crystal oscillator (VCXO) to minimize reference jitter and enhance phase noise for superior data converter SNR. With 14 low noise outputs ranging from 1 MHz to 1 GHz and a dedicated output from the input PLL (PLL1), it supports diverse communication and instrumentation applications. The device features a programmable EEPROM for user-defined power-up and reset configurations.
Applications
LTE and multicarrier
GSM base stations
Wireless and broadband infrastructure
Medical instrumentation
Clocking high speed ADCs, DACs, DDSs, DDCs, DUCs, MxFEs
Low jitter, low phase noise clock distribution
Clock generation and translation for SONET, 10Ge, 10G FC, and other 10Gbps protocols
Forward error correction (G.710)
High performance wireless transceivers
ATE and high-performance instrumentation
Operation Modes
Mode Name |
Description |
Configuration Bits |
Typical Use Case |
TRISTATE |
Set the output driver to a high-impedance state. |
Set the
|
Disable the output or leave it in high impedance. |
LVPECL_8mA |
Set the output driver for LVPECL operation with an 8mA drive current. |
Set the
|
Use LVPECL signaling that needs higher drive strength. |
LVDS_4mA |
Set the output driver for LVDS operation with a 4mA drive current. |
Set the
|
Use low-current differential LVDS signaling. |
LVDS_7mA |
Set the output driver for LVDS operation with a 7mA drive current. |
Set the
|
Use LVDS signaling with a higher drive current. |
HSTL0_16mA |
Set the output driver for HSTL operation with a 16mA drive current. |
Set the
|
Use HSTL signaling that needs higher current. |
HSTL1_8mA |
Set the output driver for HSTL operation with an 8mA drive current. |
Set the
|
Use HSTL signaling with lower current requirements. |
CMOS_CONF1 |
Set the output driver for CMOS operation in configuration mode 1. |
Set the
|
Use CMOS signaling with configuration mode 1. |
CMOS_CONF2 |
Set the output driver for CMOS operation in configuration mode 2. |
Set the
|
Use CMOS signaling with configuration mode 2. |
CMOS_CONF3 |
Set the output driver for CMOS operation in configuration mode 3. |
Set the
|
Use CMOS applications with mode 3 settings. |
CMOS_CONF4 |
Set the output driver for CMOS operation in configuration mode 4. |
Set the
|
Use CMOS signaling with configuration mode 4. |
CMOS_CONF5 |
Set the output driver for CMOS operation in configuration mode 5. |
Set the
|
Use CMOS applications in configuration mode 5. |
CMOS_CONF6 |
Set the output driver for CMOS operation in configuration mode 6. |
Set the
|
Use CMOS signaling that requires mode 6. |
CMOS_CONF7 |
Set the output driver for CMOS operation in configuration mode 7. |
Set the
|
Use CMOS applications with mode 7 parameters. |
CMOS_CONF8 |
Set the output driver for CMOS operation in configuration mode 8. |
Set the
|
Use CMOS signaling with configuration mode 8. |
CMOS_CONF9 |
Set the output driver for CMOS operation in configuration mode 9. |
Set the
|
Use CMOS applications with mode 9 parameters. |
Device Configuration
Initialization
The initialization functions manage the basic setup and removal of the
device structure and communication settings. The function
ad9523_init() initializes the device data with default values. The
function ad9523_setup() allocates the device structure, configures
the SPI interface, resets the device, and applies the initial
configuration. The function ad9523_remove() cleans up resources by
removing the SPI descriptor and freeing the device structure.
SPI Communication
The SPI communication functions handle the low-level operations to
access the device registers. The function ad9523_spi_read() reads
registers from the device using SPI, and the function
ad9523_spi_write() writes values to the device registers via SPI.
I/O Update and Synchronization
The I/O update and synchronization functions apply configuration changes
and synchronize the device settings. The function ad9523_io_update()
writes to the I/O update register to make configuration changes
effective. The function ad9523_sync() toggles the manual control bit
in the status signals register and updates the configuration to
synchronize the device.
Output Mapping and Calibration
The output mapping and calibration functions adjust the clock output
mapping and perform calibration. The function ad9523_vco_out_map()
configures the clock provider for a selected output channel by writing
to the appropriate device registers. The function ad9523_calibrate()
performs calibration of the voltage-controlled oscillator and verifies
the operation by checking the status.
Device status
The device status function monitors the current state of the device. The
function ad9523_status() checks the lock status of the VCXO and the
PLLs, and returns an error code if the device status is not as expected.
Driver Initialization Example
#include <stdlib.h>
#include <stdio.h>
#include <stdint.h>
#include "ad9523.h"
#include "no_os_alloc.h"
#include "no_os_delay.h"
#include "no_os_spi.h"
struct ad9523_channel_spec ch0 = {
.channel_num = 0,
.divider_output_invert_en = 0,
.sync_ignore_en = 0,
.low_power_mode_en = 0,
.use_alt_clock_src = 0,
.output_dis = 0,
.driver_mode = LVDS_7mA,
.divider_phase = 0,
.channel_divider = 100,
.extended_name = "CH0"
};
struct ad9523_platform_data pdata = {
.vcxo_freq = 40000000,
.spi3wire = 0,
.refa_diff_rcv_en = 1,
.refb_diff_rcv_en = 1,
.zd_in_diff_en = 0,
.osc_in_diff_en = 0,
.refa_cmos_neg_inp_en = 0,
.refb_cmos_neg_inp_en = 0,
.zd_in_cmos_neg_inp_en = 0,
.osc_in_cmos_neg_inp_en = 0,
.refa_r_div = 10,
.refb_r_div = 10,
.pll1_feedback_div = 125,
.pll1_charge_pump_current_nA = 2000,
.zero_delay_mode_internal_en = 1,
.osc_in_feedback_en = 0,
.pll1_bypass_en = 0,
.pll1_loop_filter_rzero = RZERO_135_OHM,
.ref_mode = SELECT_REFA,
.pll2_charge_pump_current_nA = 1500,
.pll2_ndiv_a_cnt = 4,
.pll2_ndiv_b_cnt = 20,
.pll2_freq_doubler_en = 0,
.pll2_r2_div = 15,
.pll2_vco_diff_m1 = 4,
.pll2_vco_diff_m2 = 4,
.rpole2 = RPOLE2_300_OHM,
.rzero = RZERO_2250_OHM,
.cpole1 = CPOLE1_16_PF,
.rzero_bypass_en = 0,
.num_channels = 1,
.channels = &ch0,
.name = "AD9523Device"
};
struct ad9523_init_param init_param = {
.spi_init = {
.device_id = 0,
.max_speed_hz = 1000000,
.chip_select = 0,
.mode = NO_OS_SPI_MODE_0,
.platform_ops = &xil_spi_ops,
.extra = &xil_spi_param
},
.pdata = &pdata
};
struct ad9523_dev *dev;
int32_t ret;
ret = ad9523_setup(&dev, &init_param);
if (ret != 0)
goto error;
printf("AD9523 initialization success\n");
goto cleanup;
#error
printf("AD9523 initialization failed\n");
cleanup:
ret = ad9523_remove(dev);
if (ret != 0)
printf("AD9523 remove failed\n");