STW8110x evaluation board and graphical user interface
Application and scope
This application note describes the evaluation board (EVB) and the graphical user interface
(GUI) of the STW81101, STW81102 and STW81103 multi-band RF frequency synthesizers
(with integrated VCOs).
The STW8110x GUI software allows the STW81101, STW81102 and STW81103
synthesizers to be programmed via an I
Three evaluation boards are available depending on the output matching network optimal
frequency range:
install Microsoft (R) .NET Framework and Windows Installer.
Follow these steps to install the STW8110x GUI:
1.If an old version of the GUI is already installed, uninstall it.
2. Run
setup.exe
(datasheets, programming configuration files and desktop/quick launch
shortcuts are optional components installed by default).
3. Run
STW8110xGUI.exe
4. The default starting operation mode is Tutorial. The starting operation mode can be
modified by means of the radio buttons in the tutorial form:
a) Tutorial: a brief tutorial on the features of the GUI.
b) Basic: only the main options are enabled.
c) Advanced: all the available options are enabled.
). It may require the installation of the Microsoft
). Administrator privileges are required to
1.2 Main form
This section details the items on the main form. See
1.Pressing this button shows the About STW8110xGUI screen.
2. Pressing this button opens the datasheet of the selected device.
3. Help
4. Device selection (STW81101/2/3).
5. GUI operation modes:
Tutorial: A brief tutorial on the basic features of the GUI. An inner default configuration
is loaded.
Basic: only the main options are enabled. Frequency values must be set in the
following order:
a) Input reference frequency F
b) Output frequency step F
c) Output frequency F
The calibrator is always ON. VCO and output divider are set automatically.
Advanced: all the available options are enabled. Any F
message will warn if the inserted values are beyond the frequency limits of the VCOs.
Frequency values must be set in the following order:
a) Input reference frequency F
b) Output frequency step F
c) Output frequency F
Waveform Viewer: a form is opened displaying the bit sequence sent to the device.
out
out
step
.
step
or F
ref
.
ref
or F
vco
Figure 1: Main form
on page 4.
.
vco
or F
are allowed. A
out
.
.
pfd
.
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Figure 1.Main form
1
5
17
6. Swallow counter A: 5-bit counter.
7. VCO calibrator:
–Last calibration F
: contains the last calibration data (VCO and frequency of
vco
calibration).
–Calibrator ON/OFF.
–The maximum allowed F
pfd
is programmed in two steps:
a) Device is programmed forcing calibration with the maximum F
(F
= F
pfd
/ R ≤ 1 MHz ==> R ≥ F
ref
b) Device is programmed with the desired F
Example with F
= 76.8 MHz:
ref
Desired values:
- F
= 1200 kHz
pfd
- R = F
ref
/ F
pfd
= 64
Forced values:
- R' = ⎡F
- F'
pfd
/ 106⎤ = ⎡76.8⎤ = 77
ref
= F
/ R' = 997.403 kHz
ref
Device programming in two steps:
a) Device is programmed with F
b) Device is programmed with F
2
6
10
14
18
78
during calibration is 1 MHz. If F
/ 106).
ref
.
pfd
= 997.403 kHz and Calibrator ON.
pfd
= 1200 kHz and Calibrator OFF.
pfd
3
11
15
19
> 1 MHz, the device
pfd
≤ 1MHz
pfd
4
9
12
13
16
20
21
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8. Output divider:
–Direct output.
–Divider by 2.
–Divider by 4.
9. Configurations:
–Load/Save: load/save a configuration file.
–Load default/Save default: load/save a default configuration.
10. Program counter B: 12-bit counter.
11. VCO. VCO settings:
–Output frequency range/VCOs frequency range: press this button to show
information on the limits of F
out/Fvco
(only for the embedded VCOs).
–VCO selection (enabled only in Advanced mode):
- EXT: external VCO. The external VCO buffer is able to manage a signal coming
from an external VCO in order to build a synthesizer using the STW8110x only as
PLL IC. The external VCO signal can range from 625 MHz up to 5 GHz. Its
minimum power level must be -10 dBm.
- VCO A/VCO B: embedded VCOs.
12. Parallel port address. Hex value of the parallel port base address:
–278: normally assigned to LPT2.
–378: normally assigned to LPT1.
–3BC
–FILE: output is saved to a text file.
13. Prescaler modulus:
–P=16
–P=19
14. Reference divider. The 10-bit programmable reference counter allows the input
reference frequency to be divided to produce the input clock to the phase frequency
detector (PFD):
F
= F
ref
/ R
pfd
where
–F
–F
: PFD input frequency
pfd
: input reference frequency
ref
Limits: 2 ≤ R ≤ 1023
15. Frequency settings:
–F
–F
–-/+: finds a lower/higher rational value for F
–F
: input reference frequency (MHz)
ref
- Limits: 10 MHz ≤ F
: phase frequency detector (PFD) input frequency (kHz)
pfd
F
= F
pfd
vco
F
vco
/ R, where R is the reference divider factor.
ref
: VCO oscillating frequency (MHz)
= N · F
pfd
.
≤ 200 MHz
ref
pfd
.
–N: PLL division ratio
N = B
· P + A.
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16. Output frequency settings:
–F
–F
–-/+: finds a lower/higher rational value for F
: output frequency (MHz)
out
F
= F
/ DIV, where DIV is the output division ratio.
vco
: output frequency step (kHz)
= F
/ DIV, where DIV is the output division ratio.
pfd
F
out
step
step
step
.
17. Charge pump current. The nominal value of the output current is controlled by an
external resistor (R
) and can be varied over 8 levels by means of 3 dedicated
ext
programming bits:
–CPSEL[2:0]: bits controlling the charge pump current
–R
–I
: the minimum value of the current is:
ext
I
= 2 Vbg / R
min
: charge pump current (mA)
cp
I
= (CPSEL + 1) · I
cp
where Vbg = 1.17 V.
ext
min
18. VCO voltage amplitude. The voltage swing of the VCOs can be adjusted over 4 levels
by means of two dedicated programming bits:
–PLL_A[1:0]: bits controlling the voltage swing of the VCO.
This setting trades current consumption with the VCO’s phase noise
performances. Higher amplitudes provide better phase noise, whereas lower
amplitudes save power.
19. Two digital interfaces are available:
2
–I
C
- ACK: if checked and the acknowledge is not received, read and write operations
fail. Uncheck this if the board is not enabled to read.
- Read: read the read-only register.
- Write: write the 6 write-only registers.
- A[2:0]: the device address (1100A
2A1A0
) must be set.
–SPI
Show sent data: the programming sequence is shown on the message list.
20. Device programming:
–Device programming modes:
- Device ON: device on with output buffer control disabled.
- Out Buffer CTRL: device on with output buffer control enabled. This control mode
allows to enable/disable the output stage by a hardware control pin (EXT_PD, pin
23) while the PLL stays locked at the desired frequency; in such a way a very fast
switching time is achieved. This feature can be useful in designing a ping-pong
architecture saving the cost of an external RF switch.
- Power Down: 'Power Down' mode enabled (device off).
–SEND: press this button to program the device.
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21. Message list: displays information, warnings and errors:
–CLEAR: press this button to delete all the messages.
Clicking the right mouse button on the message list shows a menu:
–Copy: copy the selected messages to the clipboard.
–Copy to File: copy the selected messages to a file.
–Append Mode: file is opened in append mode when 'Copy to File' is used.
–Select All: all messages are selected (double-clicking the left mouse button has
the same effect).
–Deselect All: no message is selected.
–Clear after Send: clears the message list after pressing the Send button.
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1.3 Tutorial operation mode form
Figure 2.Tutorial operation mode form
1
3
2
4
1.Help for the current GUI operation mode.
2. Start next session with: select the operation mode for the next session.
3. Always on top:
–Red: enabled
–Gray: disabled
4. The tutorial form shows a description of the evaluation board.
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1.4 Waveform viewer
Figure 3.Waveform viewer
1
3
2
1
The digital signals used to program the device can be displayed on a waveform viewer:
2
●I
C - the following are shown:
–SCL (clock) signals sent to the device
–SDA (data) signals sent to the device
–ACK signals sent from the device
●SPI - the following signals are shown:
–Clock
–Data
–Load
1.Traces can be arranged by means of the vertical sliders, or in two default positions
(separated or superimposed traces) by means of a button.
2. The checkboxes allow you to display or hide the traces and bit descriptions that
become visible when zooming in.
3. The mouse buttons have the following functions on the waveform display:
–Left: zoom in
–Right: zoom out
–Middle: pan
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2 Evaluation board
2.1 Setup
1.Connect the evaluation board to the PC parallel port via the cable included in the kit.
2. Choose which digital bus is used: the SPI or I
3. If the I
4. Connect a signal generator to the REF_CLK connector (external reference clock).
5. Connect the RF OUT connector to a spectrum analyzer.
6. Make sure that the device is not in hardware power-down (that is, ensure the switch is
The lock detector LED is turned on when the device is locked.
The nominal value of the charge pump output current is controlled by the external resistor
R15 (4.7 kΩ on the evaluation board).
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