PeakTech 1235 User manual

PeakTech
®
1235
Operation manual
32-Chanel Logic Analyser

1. Brief Introduction
Today has been a digital information age. Compared with analog technique, the
transmission and measurement of information is much different. Numerous data
channels transmit simultaneously in the spatial distribution while data code flows
are built according to certain format in the time distribution. The data code flows
are the data words taking discrete time as independent variable but not the
analog waveform taking continuous time as independent variable. Some important
parameters in analog signal analysis are not so important in digital signal
analysis. For instances, the digital signal analysis of voltage pay much attention
to voltage higher or less than some threshold level; for the analysis of time, only
the relative relations among the digital signals are noticed. So the traditional
testing device (voltmeter, oscilloscope, etc.) can not measure and analyze digital
system effectively, even not meet the requirements of circuit design and
debugging in digital system. In such a case, Logic analyzer, a new-type data
measuring instrument is manufactured to observe and measure the digital signals
in digital information processing. Some special problems of designing and
debugging in digital system are difficult to find and solve without the logic
analyzer, such as transmission delay, competition risk and burr interference. At
present, digital circuit and bus technique are used in many apparatuses. In order
to analyze and validate the result of information processing, the logic analyzer
must be used to find out the error in programming and running, measure and
compare the state of digital logic circuit. With the rapid development of digital
technique, using logic analyzer to analyze and solve the problems in digital circuit
should be mastered. But the logic analyzer in present market is so complicated to
understand and operate for teaching in universities and colleges. It is impossible
to purchase a batch for high price. So a popular logic analyzer with basic
necessary function, simple operation and appropriate price must be selected.
PeakTech
®
1235 Logic Analyzer is such a practical measuring instrument meeting
the above requirements in data field.
2. Prepare for use
2.1. Check up
Open the packing case and check whether the appearance of the instrument is
intact, accessories are all there. If the package damaged severely, please don’t
open until consult with the departments concerned.
Packing list:
Name Amount
PeakTech
®
1235 logic analyzer 1
User’s guide 1
3-core power cable 1
50 wires cables and connector 2
Input transferring boxes 2
Test hook 40
Test hook connecting cable 40
Interface demo CD 1
USB interface cable 1
RS-232 interface cable 1
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2.2. Start operation
The instrument is used with the following conditions.
Power Supply: Voltage: 100 ~ 240 V
Frequency: 60 (1±5%) Hz
Power: <30 VA
Environmental Conditions: Temperature: 0 ~ 40°C
Humidity: 80%
No powerful electromagnetic interference
Plug into the power receptacle with voltage from 100 to 240V and earthing wire,
then press the power switch on the panel to make the generator connected to
power source. Now the initialization of the generator begins. The name of
instrument and manufacturer are displayed first, and then install the default
parameters. Finally the timing waveform interface is displayed.
Warning!
For manipulator’s safety, triple socket with safe earthing wire must be used.
3. Principle summarize
When sample the external signal source, the external signal is sent into the
positive input port of the high-speed comparator via the input circuit. The
threshold circuit generates a threshold voltage according with the setting values,
and sends the voltage to the negative input port of the high-speed comparator. A
TTL level digital signal is generated by the comparison of the two signals and
then the digital signal is stored synchronously in the data flip-latch by sampling
clock. When sample the internal code, the code generator will produce 30
channels of internal digital signals which are stored synchronously in the data
flip-latch by sampling clock. The sampling data in the data flip-latch are stored in
high-speed memory according to appointed address.
Selecting the internal clock in timing sampling can set the cycle of sampling clock.
State sampling with external clock can select the phase of sampling clock.
During the period of sampling storage, a “sequence add 1 counter” supplies
storage address for the high-speed memory in memory control circuit, each
sampling clock makes the memory change to a new writing address. At the same
time the flip-latch sends a new sampling data, so a new data is stored in the
memory. The start-up and end of the address counter is determined by the
memory control circuit according to the parameters of triggering process. After
sampling storage, Micro controller unit reads a series of data and send them to
the LCD which will display the timing waveform and data list.
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The work principle is shown as the following diagram.
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Read/write
data
Sampling
circuit
Sampling
rate
read/write
data
Keyboard
Input
Storage
address
generator
High-speed
comparator
Threshold
voltage
High-speed
memory
MCU
T
rigger
process
External
signal
Clock circuit
Internal code
generator

4. Display and keyboard
4.1. The panel of the instrument
Front panel
1. Power switch
2. Display screen
3. Display control keys
4. Data input keys
5. Cursor key
6. Sample key
7. Function keys
8. Signal input
9. Signal input
10. Adjusting knob
AC 100-240V
45-65Hz 1A
REPLACE FUSE
AS SPECIFIED
DISCONNECT POWER CORD
BEFORE REPLACING FUSE
RS-232USB
3. 2. 1.
Rear panel
1. Power source outlet
2. RS232 interface
3. USB Device interface
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1. 2. 3. 4.
5.
6.
7.
8. 9.
10.

4.2. Keyboard description
There are 34 keys on the front panel, functions are following:
4.2.1. Function optional key (8 keys)
【Channel】:select and set the sequence order, name, color and switch of
each channel in cycle.
【Threshold】: select and set the threshold voltage.
【System】:select and set the system parameters.
【Trigger】:select and set the parameters and the switch in the trigger
process.
【Time/State】: select the mode of timing sample or state sample in cycle
【Source】:select internal code generator or external signal source in cycle.
【Save】:save the current setting parameters.
【Recall】: recall the last saved setting parameters
4.2.2. Sample control (2 keys)
【Run/Stop】: circular run/stop recycling sample
【Single】: single sample
4.2.3. Number input (11 keys)
【0】【1】【2】
【3】【4】【5】
【6】【7】【8】
【9】: number input key
【x】: special characters x, only used for data search input
4.2.4. Input control (4 keys)
【↑】【↓】: select the setting parameters up to down in cycle
【←】: backspace, to delete the input data when the input hasn’t
finished
【Shift】: used for input the English letters above the button
4.2.5. Display control (5 keys)
【Display】: display timing waveforms or data lists in cycle.
【↑↓】:use the knob to roll timing waveforms and data lists up and
down
【←→】: use the knob to roll timing waveforms and left and right
【Zoom】: use the knob to zoom timing waveforms
【Find】: find and display the data points suited the search conditions
4.2.6. Control knob (2 keys)
【Cursor 1】: use the knob to move the cursor1 left and right
【Cursor 2】: use the knob to move the cursor2 left and right
4.2.7. Working state (2 keys)
【Reset】: initialize the instrument and resume the default parameters
settings
【Language】: Only English interface
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4.3. Display description
On the top of the display screen, there are some words shown the function and
the operation of the button you pressed (except the numeric keys).
There are 3 types of display interface under the denotation words, details are
following:
4.3.1. Waveforms display interface
The waveforms display frame is on the top of the display interface which displays
eight channels of timing waveforms, the serial number and the name of the
waveform, four different colors vertical cursor lines. There is one scale on the top
of the waveform frame, and another one is on the bottom of the waveform frame.
They are the zoom scales, the time value of every scale varies with the zoom
coefficient. Below the waveform frame is the parameters display frame, the six
parameters on the left is the state parameters, varies automatically with different
operations, showing the current state of the equipment. The six parameters on
the right is the parameters settings of the system, can be set with number keys.
4.3.2. Data display interface
The data display frame is on the top of the display interface which displays 19
rows of data, each row is one sampled data point in the memory, corresponding
to 32 sample channels. The three columns of data from left to right is the address
of data, the data value in Dec, the data value in Hex, the data value in Bin. The
parameters display frame is below the data lists frame, the three parameters on
the left is the state parameters, changes automatically with different operations,
showing the current state of the instrument. The two parameters on the right is
the parameters settings of the system, can be set with numeric keys.
4.3.3. Trigger settings interface
The trigger settings interface displays the whole trigger process. Adopting the
graphical mode makes users can easy to understand the whole trigger process.
The panes in the display interface is the nodes of the trigger process, the connect
lines among the panes show the direction of the trigger process, six parameters
can be set on the right, the left side have six switch can be set, the specifications
of the setting shows in the chapters behind.
5. Instructions for use
5.1. Starting initialization
Press the power button to connect the electricity supply. Firstly the model number
and the manufacturer of the instrument will be showed on the screen. Please
operate the initialization program and load the default parameter settings. Then
the timing waveforms of internal code will be displayed. All kinds of operational
practice can be carried out without connecting with the external input signals.
Most of the researching objects of the logic analyzer are single or non-cyclical
signals included in high speed data stream. So the analyzer can’t display the
signals in time on the screen as the oscilloscope does, but can sample the
signals according to certain time (sample clock). It can catch and save the
interesting signals by setting up the suitable trigger process. The saved data can
be recalled showing on the screen and researched repeatedly.
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5.2. Operation general principles
5.2.1. Keyboard description
When any key is pressed, there is a corresponding hint on the screen which
explains the function and the operation of the key. If there is a circular symbol,
consisting of two arrows laid end to end, on the left of the hint, then it is a cycle
key. It runs different functions by pressing it repeatedly. If there is no circular
symbol, the key has only one function.
5.2.2. Parameters input
If there are reverse numbers or characters on the screen, means the parameter is
a selected one which can be set by pressing the keys. If the user needs to select
other data, 【↑】and【↓】can be used. The user also can turn the knob left and
right to select other data cyclical. If input the wrong characters or numbers, user
can delete them one by one by pressing 【←】. As soon as the reverse
characters areas are filled with numbers, the parameter settings take effects.
Meanwhile the【←】doesn‘t work anymore, unless restarting input process.
5.2.3. Letters input
The 26 letters, from A to Z, are marked on 26 keys. During the process of
parameter input, press【shift】key and release the key, then input the letter you
need. If there is no letter on the key, user can input space. The【shift】key is a
one-kick. So if the user needs to input the next letter, please repeat the
operations above.
5.3 Channels setting
5.3.1. Channel order setting
The double digits number 00-31, on the most left of the waveforms display frame,
is the channel serial number. Press【Channel】key to select the channel serial
number setting. Then set the channel sequence by numeric keys. The settings
only change the position of channel waveforms on screen so that some channels
of waveforms can be closely displayed and easily compared. However the real
positions of sampling channels are not changed, the sampled data too. If the real
positions of sampling channels need to be changed, user has to change the
connection of the test nips for sampling on the circuit board.
5.3.2. Channels label setting
The four characters on the right of the channel serial numbers are the label of the
channel. Press 【Channel 】key to select the channel label setting. Set the
channel label by numeric keys or letter keys. Every channel label can be set by
user.
5.3.3. Channels color setting
Press【Channel】key to select channel color setting. Set the color by numeric
keys. Every channel can be set according to user’s favorite color.
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5.3.4. Channels switch setting
Press【Channel】key to select channel switch setting. Set the channel “on” by
using the numeric key【1】. Set the channel “off” by using the key【0】. The
settings will take effect in the process of next sampling display.
The settings of the channels are complicated but there is no need to change them
frequently. Press【Save】to save the self-defined channel settings so that you
can use it when you need without reset the settings.
5.4. Thresholds setting
Press 【Threshold】key to select threshold voltage setting. The 【↑】and【↓】
pushbuttons are used to circularly select one of the six threshold voltages. Only
knob can be used to set the value of threshold voltages in a continuous manner.
The voltage will increase by turning the knob to right and decrease by turning the
knob to left. When the voltage value passes the zero, the polarity sign will
automatically change. The internal code-generator doesn’t pass the voltage
comparator, so the settings on threshold voltage aren’t valid when sampling the
internal code.
The analyzer has 32 external signals input channels and 2 external clock
channels. The best performance is when the peak-to-peak value of input voltage
is between 500mVpp and 20Vpp. The maximum input voltage handle is ±40V.
After accessing the analyzer, the input signal first passes through the voltage
comparison circuit and is compared with the threshold voltage set by the user. If
the input signals are higher than the threshold voltage, the analyzer shows the
number “1”, otherwise it shows the number “0”. Then the signals are sampled and
saved and displayed on the screen.
Waveforms displayed by this means only reflect the timing logic when the input
signals are higher or lower than the threshold voltage. It doesn’t reflect the real
amplitude of the input signals, and may be far different from the real waveforms
of the input signals. This kind of waveforms displayed by logic analyzer is usually
called a “pseudo waveform”.
In practical operation, the sampled signals appear by groups. For example,
grouped by the data bus or the address bus .The characteristics of amplitude of a
group of signals are the same, so use the same compare threshold voltage. In
practical operation, there are many kinds of signals with different amplitude to be
tested such as TTL, CMOS and ECL. In every experimental circuit, the amplitude
characteristics of signals may be various. To satisfy these conditions, the
instrument is deployed with six individual adjustable threshold voltages. Four of
them are used in four channel groups which contain 8 signal input channels in
each one. And the other 2 threshold voltages are used in 2 external clock input
channels.
In practice, the instruments measure signals mostly in groups, for instance in the
total line and address line. The amplitude characteristic of one group is identical
and should use the same comparison threshold voltage. However the instrument
has 32 signal input channels and again, it is not necessary to setup 32
independently adjustable threshold voltages. But in practice, there are signals
measured with different amplitude for instance TTL, CMOS, and ECL.
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In many experiment circuits, the amplitude required may vary. For this application,
6 independently adjustable threshold voltages are configured in instrument, 4 of
which are used for 4 channel groups, each group has 8 signal input channels.
The other two are used for 2 external clock input channels separately.
In practice, the electrical sources of +5V or +3.3V are usually used in digital
system. So all default settings of the threshold voltage are +1.6V. Generally
speaking, the setting range of the threshold voltages for TTL is between +5V and
+3.3V. And the setting range of threshold voltages for CMOS is between +5V and
+4.3V. If the tested signals contain large ringing effect or other noises, there are
wrong data in the sampled results. When it happens, repeat sampling function to
adjust the threshold voltage and observe the sampling waveforms, until clear and
correct sampling waveforms are obtained.
5.5. Display setting
The PeakTech
®
1235 logic analyzer can display a vast amount of data. There are
two display modes of the sampling data: timing waveform display and data listing
display.
5.5.1. Timing waveform display
Press【Display】to view timing waveforms for up to 8 channels displays. Each
channel can be displayed with different color to easily indentify and separate
them visually. The order of 32 channels waveforms is that the highest channel is
on the top and the lowest channel is at the bottom. This is to enable the highest-
order digit of the byte to be on the top and the lowest-order digit on the bottom.
5.5.2. Waveform rolling Up/Down
The waveform rolling can be used to observe all the waveforms in 32 channels.
Press 【↑↓】and turn the knob to browse the waveforms. If there is a need to
compare the waveforms, the method of channel order setting (5.3.1) can be used
to display the desired waveforms.
5.5.3. Waveform rolling Left/Right:
The PeakTech
®
1235 allows for 260,000 memory addresses for each channel,
however only 280 data points can be viewed due to the horizontal width of the
screen. In order to display the needed blocks from the mass of stored data, the
screen display window aim at any position in memory. This requires setting a
changeable “window address” for display window, as long as changes the window
address, the screen of analyzer will show the storing data block taking this
address as initial point.
Parameter in the first row on the right bottom of the wave frame is the window-
addr. The waveform displays the data on the most left, that is the data
corresponding to the window address in sampling memory. Press【System 】to
select window-addr and can set the window address in Dec numbers with the
range of 0~260000. After setting, the waveform of sampling storing data block, to
which this window address corresponds, will display immediately. If one needs to
continuously observe a waveform nearby the window, press【←→】and turn the
knob, the window-address will change continuously, as if the waveform is rolling
from left to right in the display window.
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