PLL click
PID: MIKROE-2993
Weight: 27 g
PLL click is a frequency multiplier which uses the Phase-Locked Loop (PLL) techniques to
provide a high-frequency clock output from a cheap, standard fundamental mode crystal
oscillator. In addition to this, PLL click also offers a choice between nine different
multiplication factors, programmed via states of the two input pins. The output range of the
PLL click goes up to 160MHz.
Besides the fixed 12MHz crystal oscillator, PLL click can also use a PWM signal source
brought from the PWM pin of the mikroBUS™, offering a possibility to continuously adjust
the output frequency. Featuring a very precise PLL multiplication, very low output jitter of
25ps, tri-state output for board level testing, both onboard and external clock inputs, ability
to change clock “on the fly”, compatibility with all the 3.3V and 5V MCUs, and selectable
multiplication factor, this Click board™ can be used for development and prototyping of
various applications which can benefit from having an adjustable system clock generator,
or for any general purpose application that demands cheap solution for the high-speed
system clock.
How does it work?
PLL click is equipped with the ICS501, a LOCO™ PLL clock multiplier, from Integrated
Device Technology. This IC uses the Phase-Locked Loop to provide a high-frequency clock
output, deriving input from a much cheaper, standard fundamental frequency crystal
oscillator. Besides the onboard crystal oscillator fixed at 12MHz, it is possible to select the
signal from the mikroBUS™ PWM pin as the clock input source.
To select the desired multiplication factor, the states of the two input pins S0 and S1,
routed to the mikroBUS™ pins RST and AN, respectively. These pins can be set to a HIGH
logic state, LOW logic state, or can be disconnected (by tri-stating the MCU pins). The
combination of these pins states will set the PLL click to a specific multiplier. To set the
multiplication factor of the PLL click, please consult the multiplication selection table,
below.
The Output Enable (OE) pin of the ICS501, is used to disable the output clock, by setting it
to a LOW logic level. It will additionally set the clock output pin in high impedance (Hi-Z)
mode, allowing complete disconnection and no influence on the rest of the circuit, which is
useful for experimenting and prototyping purposes. This pin is internally pulled to a HIGH
logic level. The OE pin is routed to the CS pin of the mikroBUS™.
PLL click is equipped with two onboard SMD jumpers. The SMD jumper labeled as the VCC
SEL is used to select the operating voltage level, consequently limiting the amplitude of the
clock output signal, in respect to the selected voltage. The other SMD jumper labeled as the
OSC SEL is used to choose the clock input source between the onboard 12MHz crystal
oscillator or the external clock signal. The output signal is routed through the onboard SMA
connector, which provides a secure connection and good signal shielding.
PLL click comes with the library that contains functions for all the MikroElektronika
compilers (mikroBASIC, mikroPASCAL, and mikroC). Although relatively easy to control it,
the library offers comprehensive functions that make the code more readable and are easy
to use. The included example application demonstrates the use of these functions and it can
be used as a reference for custom projects.
Specifications
Type
PWM
Applications
PLL click can be used for development and prototyping of
various applications which can benefit from having an
adjustable system clock generator, or for any general
purpose application that demands cheap solution for the
high-speed system clock.
On-board
modules
ICS501, a LOCO™ PLL clock multiplier, from Integrated
Device Technology
Key Features
Precise PLL multiplication, very low output jitter of 25ps,
the tri-state output for board level testing, both onboard
and external clock inputs, etc.
Interface
GPIO
Input
Voltage
3.3V,5V
Click board
size
M (42.9 x 25.4 mm)
Pinout diagram
This table shows how the pinout on PLL click corresponds to the pinout on the mikroBUS™
socket (the latter shown in the two middle columns).
Notes
Pin
Pin
Notes
Multiplier
adjustment pin 1
S1
1
AN
PWM
16
ICK
Multiplier
adjustment pin 0
S0
2
RST
INT
15
NC
Output enable
OE
3
CS
RX
14
NC
NC
4
SCK
TX
13
NC
NC
5
MISO
SCL
12
NC
NC
6
MOSI
SDA
11
NC
+3.3V
7
3.3V
5V
10
+5V
Power supply
GND
8
GND
GND
9
GND
Ground
Power supply
Ground
External clock
source
PLL click specifications
Description
Min
Typ
Max
Unit
Input frequency - crystal input
-
12
-
MHz
Input frequency - clock input
2
-
50
MHz
-75
-
75
ps
Absolute clock period jitter
Onboard settings and indicators
Label
Name
Default
Description
LD1
PWR
-
Power LED indicator
JP1
VCC SEL
Left
Power supply voltage selection: left position 3V3,
right position 5V
JP2
OSC SEL
Left
Input clock signal source selection: left position
onboard 12MHz crystal oscillator, right position
external clock from PWM pin
Software support
We provide a library for PLL click on our Libstock page, as well as a demo application
(example), developed using MikroElektronika compilers and mikroSDK. The provided click
library is mikroSDK standard compliant. The demo application can run on all the main
MikroElektronika development boards.
Library Description
Initializes and defines I2C driver and driver functions which offer a choice of writing in
registers and reading from the registers. The library also has the ability for light
measurements. The library can measure Small, Medium, and Large IR light, White and
Large White light and UV and Deep UV light, whose values can be 16-bit or 24-bit. The
library also offers a choice between channels that the user wants to measure desired light.
For more details check the documentation.
Key functions:
void pll_setClockOutput(uint8_t mode); - Function for enabling and disabling of the
clock output.
void
void
void
void
void
pll_setPLL_3x(); - Function for multiplying of the clock 3 times.
pll_setPLL_4x(); - Function for multiplying of the clock 4 times.
pll_setPLL_5x(); - Function for multiplying of the clock 5 times.
pll_setPLL_6x(); - Function for multiplying of the clock 6 times.
pll_setPLL_8x(); - Function for multiplying of the clock 8 times.
Examples Description
•
System Initialization - Initializes CS pin, RST pin and AN pin as an output.
•
Application Initialization - Initializes driver init and set mode chip as ACTIVE.
•
Application Task - (code snippet):
•
Every 2 seconds, the PLL increases the input clock in the order of x4, x5, x6, and x8.
•
If you use PLL x4, x5, x6 or x8, set S0 (RST pin) and S1 (AN pin) as OUTPUT.
•
If you use PLL x3.125 or x6.25, set S1 ( AN pin ) as INPUT and S0( RST pin ) as OUTPUT.
•
If you use PLL x3 or x5.3125, set S0 ( RST pin ) as INPUT and S1 ( AN pin ) as OUTPUT.
For the test, the onboard crystal oscillator is used where the frequency of the input clock is fixed. Using
ICK (PWM pin) as input, it allows continuous output frequency setting to be in a wide range.
void applicationTask()
{
pll_setPLL_4x();
Delay_ms( 2000 );
pll_setPLL_5x();
Delay_ms( 2000 );
pll_setPLL_6x();
Delay_ms( 2000 );
pll_setPLL_8x();
Delay_ms( 2000 );
}
The full application code, and ready to use projects can be found on our Libstock page.
Other mikroE Libraries used in the example:
•
Conversions
•
I2C
•
UART
Additional notes and information
Depending on the development board you are using, you may need USB UART click, USB
UART 2 click or RS232 click to connect to your PC, for development systems with no UART
to USB interface available on the board. The terminal available in all
MikroElektronika compilers, or any other terminal application of your choice, can be used
to read the message.
mikroSDK
This click board is supported with mikroSDK - MikroElektronika Software Development
Kit. To ensure proper operation of mikroSDK compliant click board demo applications,
mikroSDK should be downloaded from the LibStock and installed for the compiler you are
using.
For more information about mikroSDK, visit the official page.
Downloads
mikroBUS™ Standard specification
LibStock: mikroSDK
Libstock: PLL click library
ICS501 datasheet
PLL click schematic
PLL click: 2D and 3D files
https://www.mikroe.com/pll-click 5-11-18