Development board diagram for avr
The debug board is quite a useful tool when developing various electronic devices. But is it possible to create it yourself? Or should we rely only on industrial analogues? What features does this device have? This is what we will talk about today.
general information
When they talk about this topic, they most often mean a debug board for Atmega8 or another similar microcontroller, which is based on an 8 or 16-bit operating principle. But the world moves forward. The time is coming for 32-bit microcontrollers. In this regard, we will consider what may be available to us now. Particular attention should be paid to the STM32 development board, although AVRs are still considered in the article. But first, let's present the big picture.
The advent of 32-bit microcontrollers made it possible to significantly expand the scope of tasks that they could perform. But it is necessary to optimize the decisions made and the equipment created. Although attention will be paid to old samples, because it is simply impossible not to note their versatility and good quality.
What is STM32?
Of course, the debugging board is of greatest interest in the article. But to understand the additional point, let's look at the main one. Let's say we have STM32F103C8T6. The debug board is a design with a microcontroller based on the ARM Cortex-M3 core. It has a significant number of advantages, the main one being versatility. By the way, Cortex-M3 is now a full-fledged industrial standard. The development board is a surface on which all STM32 legs can interact, ensuring the execution of existing tasks.
Let's start preparing
So, we need a debug board. What parameters should it have? Buy it or make it yourself? What size should it be? We'll start with the last question. Initially, it is necessary to select a device so that all mechanisms and components can be successfully placed on it. In most cases, it is enough that the development board for the AVR has sides of fifteen centimeters. This size is suitable due to the compactness and capabilities of the device.
Before you start making or buying a board, you must first draw up its diagram. To do this, you can lay out the elements on paper and draw connection lines between them. If everything worked out without problems, great, then you can begin practical actions. Then you just need to place and solder all the required elements, and that’s it - the board is ready. This is what it looks like in a nutshell. Now let's look at everything in more detail.
Planning
The need to use debug boards sooner or later overtakes every radio amateur. This is a kind of debugging at the hardware level. If you wish, you can buy a ready-made board for every taste. But we are interested in a detailed analysis of this topic? Therefore, we will look at how to create a debugging board with your own hands.
Initially, you need to decide whether we are developing a board for specific needs or making a universal one. Since the first option is quite specific, the second will be considered in the article. You need to think about the foundation. If you look at most random amateur boards, they look very sloppy. Wires stick out in any direction, and it can be somewhat difficult to see what is connected to what. Therefore, it is necessary to provide for the possibility of securing them so that they do not intersect.
If you create it for a specific case and develop a scheme, you can etch the tracks. This option is the most interesting. By the way, a quite popular situation is when a universal scheme is used, and tracks are either applied or removed. To understand better, let's look at a few examples.
Power board
Let's say we are building something significant in size, and our device consists of several modules. In this case, the debug board circuit must provide for the possibility of obtaining DC or AC voltage at the input. To achieve multiple connection methods, you need to think about connectors and terminal blocks. To ensure operation, it is necessary to provide not only batteries, but also a stabilizer. And in case of light overloads and accompanying overheating, you can use a small radiator.
Microcontroller board
Here comes the most interesting part. It is quite possible that development boards for microcontrollers and auxiliary elements are the most complex components. After all, they are the “brains” of technical devices. For a successful start in the field of development boards, it is not advisable to start with complex 32-bit controllers. You can start with something simpler. For example, from the veteran of mechatronic development ATmega8. In order not to further complicate the situation, you can get by with building a one-sided print.
But what if the requirements go beyond these limits? Use double-sided printing? As an option - yes. But if the excess of capabilities is insignificant, then you can often do without mounting jumpers. It is better to place the port connectors and suspender chains on separate miniature handkerchiefs. This approach will make it easier to wire the microcontroller board. But this is just a general theory. Let's talk about implementation in practice.
Manual PCB Manufacturing
Initially, we need paper on which the layout for the printed circuit board will be drawn. It is desirable that it be thin. This is important for achieving accurate hole drilling. To avoid any surprises, the paper can be glued to the cardboard using glue. Next, cut out the glued pattern. Well, the template for drilling is already ready. We select a foil fiberglass blank of the required size. We attach a paper and cardboard template and outline it around the perimeter with a pencil or marker. Then we cut the fiberglass along the lines we drew using metal scissors, or we saw it with a hacksaw. Glue the parts together with glue.
By the way, a little advice: you don’t need to smear the entire surface, just leave a drop of glue in each of the four corners. If you don’t want to wait, use “Moment”. It will allow you to continue working after a few seconds.
Drilling holes
A special mini-machine is best suited for this purpose. But you can also use manual tools. For the vast majority of purposes, a drill with a diameter of 0.8 mm is more than enough. It should be noted that a high-quality board may not work out the first time due to the complexity of the work and the need to have a steady hand. If such actions are carried out for the first time (and most likely this will be the case), then we can only advise you to mentally prepare for the fact that the drills will be broken. After completing the entire range of work, to make sure of their quality, look at the light. If certain defects are noticeable, they must be promptly eliminated.
Applying a topographic drawing
The places where the conductive paths will pass must be protected from destruction during etching. To do this, they are covered with a special mask. All foreign substances must be removed before application. This especially applies to glue that may have accidentally leaked onto the surface.
Once the paths are marked, we can begin the process of drawing. Waterproof enamel (any) is suitable for this purpose.
Transferring the design from paper to fiberglass
This is the most critical stage. It is necessary to apply the paper (the side where the drawing is) to the fiberglass and press with great force. Then we heat the resulting “sandwich” in the oven to a temperature of 200 degrees. We wait until the board cools down to room temperature. After this, all that remains is to tear off the paper - and the design will remain on the printed circuit board. This may seem quite difficult, especially with the temperature. Especially for such doubtful people, some craftsmen suggest using an electric iron. But one important warning should be made here: the result is unstable. Of course, you can try to practice for a day or two, and perhaps it will be no worse than in the case of the stove. But there is still the problem of the difficulty of ensuring simultaneous heating of the surface throughout the entire printed circuit board to the same temperature. Therefore, the drawing is not completely transferred in this way.
The most significant problems are caused by the gaps that arise during such creation. For safety, while “cooking” the printed circuit board in the oven, it can additionally be covered on different sides with sheets of metal five to six millimeters thick. This is done to avoid negative deformation during heat treatment of the board.
Conclusion
So, in general, the board for AVR is ready. Of course, a universal method is described here, and everyone will have to complete it for specific conditions independently, focusing on their needs. You can also experiment with creating universal boards. Each craftsman constantly improves them in some way so that they are better and of higher quality. In addition, their development makes it possible to ensure the reliability of the created circuits.
Another simple example of making a debug board, but this time for devices using the ATTiny2313 microcontroller. The location of the programming feet for the ATTiny2313 is identical to the ATTiny13. Accordingly, the boards will be similar. The difference will be the presence of an external master oscillator (quartz). By default, the ATTiny2313 is supplied from the factory with an internal oscillator enabled, so if the microcontroller is not planned to operate from an external oscillator, it can not be installed. We duplicate the power connector in case of connecting a programmer powered by the circuit to the board (we supply power to one connector, and power the programmer from the other).
To make a debug board for devices based on ATTiny2313 we need:
We assemble the debug board according to the drawing:
1 is soldered into a socket for the microcircuit and pins (as in the picture);
2, as shown in the figure (red line), we make a jumper on the front side of the board. We make another jumper on the other side;
Using 3 “snot” jumpers we connect the pins and legs of the socket (the soldering points are circled in green).
Our development board is ready!
Conclusion.
— We put marks on GND, SCK for the correct connection of power and programmer;
— Everything else on the debug board will be soldered according to the selected device circuit. (as an option, you can solder pins to each leg of the microcontroller to connect other boards and peripherals);
— For more reliable operation in conditions of increased noise, it is very desirable to supplement the circuit with a resistor that pulls up the reset pin to the power supply (the internal pull-up resistor has a resistance of about 10 kOhm - this is not enough) and a filtering ceramic capacitor on the power pins (within 0.1 μF);
-Now we insert the microcontroller into the socket and use the ATTiny2313 to flash it with the required firmware.
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A simple development board for AVR ATTiny2313 devices with quartz.: 70 comments
- GetChiper Posted by
Did you touch the fuses?
Did you check it on another Tini2313? - Toxa12345
I was tormented for a long time about: “WHAT MK to choose?” I settled on Tinka 2313 because it is cheaper than ATMEG, and is not as expensive as Tinka 13, also due to the presence of RxD and TxD lines, which allows communication via South Africa
ZY It’s not a problem to buy MK here in Kursk. Tinka 2313 costs 130 rubles. and atmega8 as much as 200 rubles didn’t find out about Tink 13 - GetChiper Posted by
Or maybe ATmega88 or ATmega48?
- Andrey1979
Good time.
I assembled the board according to the proposed scheme, connected it to USBasp, connected 2313, applied 5 V. Extreme Burner gives Incorrect Chip Found. Accordingly, it is impossible not to flash anything. The same thing happens when replacing the tin.
Has anyone encountered anything like this?
Perhaps this is due to interference?“- For more reliable operation in conditions of increased noise, it is very desirable to supplement the circuit with a resistor that pulls up the reset pin to the power supply (the internal pull-up resistor has a resistance of about 10 kOhm - this is not enough) and a filtering ceramic capacitor on the power pins (within 0.1 µF); »
and also, especially for dummies, is it possible to reflect these actions in the form of a diagram.
- GetChiper Posted by
What to display there.
The capacitor is placed parallel to the power supply (i.e. between legs 10 and 20)
A 10 kOhm resistor is placed between Vcc and reset (i.e. between pins 1 and 20) - Andrey1979
Thanks for the answer. I set it to 4.7 KOhm and 220pF. It became a little more fun. extreme burner writes the same as it was. But khazama every other time reports The chip signature is 0x1e000. MISMATCH Expected signature for ATTiny 2313 is 1e 91 0a. In other cases it also writes a connection error.
I'm using a solderless breadboard, so there shouldn't be any problems with dirty soldering. Where else can you look?
- GetChiper Posted by
220pF is not enough. You need 0.1 µF - ceramic (non-polar) and 10-100 µF electrolytic (polar) in parallel.
- Dederik
good afternoon))) I didn’t find quartz 20,000, instead I was only able to find quartz 4,000. If I install quartz 4,000, will my micro-r slow down? And the same capacitors need to be changed for quartz 4,000? I live in Samarkand with radio spare parts we have a problem(((I don’t even know where to find a socket for microcon-r(((is it possible to make a socket for micro-r yourself?
- Dederik
at least someone answer)))
- GetChiper Posted by
Calm down - it was the weekend :)
You can use any quartz if you plan to study and make your own devices using this scarf (there is no need to change capacitors for quartz). Or you can skip installing quartz at all and use the built-in RC oscillator.
As for making a socket, maybe just solder the MK to death in a breadboard?
- Dederik
thanks for the help))) I have one more question for you, but I don’t know where to ask ((((today they brought me an electronic meter for repair Holley DDS28. I dug around there and found a micro-p Fudan FM24C02 there which answers for the meter readings. The entire record is stored in the micro-record. Can you tell me how to make a programmer for it so that you can read and edit the micro-record data???
- GetChiper Posted by
FM24C02 is a serial non-volatile memory (EEPROM)
I think there are many cords and programs for this matter (if you ask a search engine) - here is the first one that comes up http://www.msplata.ru/teleprog.html - Dederik
Thanks for the help:-)
- kosmogon
I believe that you need to start with practice, so I will not consider emulators.
To begin with, you need a programmer, but there is a ton of information about this on the Internet, so I will only touch on the surface. The simplest of them is the so-called “5 wires”, it is easy to do - we take an LPT cable and connect it to the MK through resistors, as shown in the figure:
You need to do everything extremely carefully, burn the LPT like this - at once.
It is much better to do something more decent - for example USBasp, it is safer and works via USB.
An alternative is to buy a programmer from Voltmaster or Chip-and-Dip.
The parameters are not so important to begin with, except for the price and supported chips.
Essentially everything. Crystal + programmer + desire and aspiration, this is enough to start programming the MK. But the organization of the circuit itself and the periphery (piping) of the MK also plays a very important role.
You can, of course, make a printed circuit board for each case when you want to play around, but I am for more universal and faster solutions.
Of course, there are breadboards, but to me, a web of wires and jumpers looks terrible, unreliable and, most importantly, not visual (and this is important during development and training).
There are development boards for various microcontrollers. And everything about them is good, except the price (the simplest one is from 2-3 thousand rubles - it’s certainly worth it, but that’s what amateur radio is for, to do it yourself if possible). Therefore, I decided to create my own simple debugging board that would meet my requirements.
What were the requirements for this board:
- Ease of execution
- Visibility
- Versatility
- Cheapness
- Easy to create test device
- Availability of LCD display
- Built-in keyboard
- 2 free ports (with the ability to use them at your discretion)
- COM port on the board for integration with a computer
What was used in production:
- Fiberglass one-sided ~70r
- Pads for connecting peripherals and switching (pins like on motherboards on which jumpers are hung) ~50r
- Tact buttons - ~ 50r
- Socket for microcircuit 30r
- Connector for COM port 20р
- Chip MAX232a 50r
- LCD indicator - from 250r
- The ATmega32 chip itself starts from 200 rubles
This is what I ended up with:
2. Wiring
Now, in order. Let's start with the board layout in Sprint-Layout. In fact, this is the most crucial moment in creating a device; you need to take into account all the nuances, and at this moment you need to understand what exactly is required from the board, how it should look, how it is more convenient. Therefore, I don’t recommend repeating it blindly; it’s worth sitting down and looking through the analogues, identifying interesting solutions or components for yourself. I got it like this:More details about the periphery; for this you should look at the pinout of the crystal: 
- On PORTA There will be a hanging keyboard - 7 buttons arranged so that they can be used to navigate, for example, through the menu (crosspad), and a couple of buttons for additional functions.
- on PORTB I placed the LCD display in the same way as provided in codevision avr using standard means (three display command registers and 4 data registers are used)
- PORTC And PORTD brought out with pads for connecting peripherals. I also provided collet panels next to the blocks, but I didn’t have them in my household and their installation was postponed until better times
- I also placed a max232 with capacitors and a COM port connector.
- For versatility, each pin of the controller is connected to blocks parallel to the socket for the microcircuit.
- programming pins SCK, MISO, MOSI and RESET are duplicated by another row of pads
3. Making a signet
As soon as the board was separated, a signet was made using a laser iron. There is no point in dwelling on the method, since it has been described hundreds of times on the Internet, and at least . Result:4. Final stage
Then we drill, tin, and solder our board.5. Conclusion
And now, our debug board to simplify development on the MK is ready. Now, in order to learn how to work with the functionality of the AVR MK, we don’t have to sculpt a tangle of wires. We simply connect the necessary peripherals to free ports (be it LEDs, sensors, drive and servo drivers, and much more), and calmly write the program.In conclusion, I want to say that the appearance and functionality of this board were formed on subjective requirements and desires, and everyone who wants to make such a device must sit down and think about the statement of the problem and requirements.
All the work took one evening.
The article described the assembly of an important part of our debug board - the power circuit. It is worth saying that the power supply does not always have to be on any development or development board. If you already have a ready-made power supply in the form of a finished design, then you can use it. So-called “laboratory” power supplies, which have one or more standard output voltages, often adjustable, have also become widespread. You can also assemble such a power supply yourself or purchase a ready-made one. Then you won’t need to assemble a power supply circuit for test structures each time.
Let's continue assembling our debug board. This time we will install a microcontroller on it, connect some LEDs and run the first program on it.
First of all, let's prepare the necessary details:
Rice. 1. Basic details.
Let's take the AVR microcontroller ATmega8 as a basis. This is a fairly powerful microcontroller with a large amount of memory and a variety of peripherals. You can also use any other microcontroller. An example of using the ATtiny2313 microcontroller on this debug board can be found in another version of this text at the link:.
As always, the first thing after choosing a part is to familiarize yourself with the location of its pins and main characteristics. All the necessary information for ATmega8 is contained in it. Remember, almost all microcontroller pins can have multiple functions. These functions can be selected when writing a program for µC. And you should pay attention to this already at the stage of drawing up a schematic diagram. In addition, already in the process of drawing up a diagram, it is convenient to use the symbol of parts with “live” pinouts, that is, when designating a part on the diagram, draw the pins as they are actually located. Then the placement of components both on the diagram and on the board will be simpler, clearer and with fewer errors. (Almost all schematic editors have the ability to draw your own part symbol.)
Let's draw a diagram:
Rice. 2. Circuit with ATmega8 microcontroller.
Quartz resonator Q1 with capacitors C1 and C2 form a clock source for the microcontroller µC1. This is a very noise-sensitive part of the circuit, so the conductors for it should be selected to a minimum length, and nothing else should be connected to the conductor between C1, C2 and the eighth leg µC1 (thickened line in the diagram). Resistor R1 and capacitor C3 form a reset circuit for the microcontroller. Resistors R2-R5 are necessary to limit the current through LED1 -LED4. There is a blocking capacitor C4 in the power circuit. We will use the stabilizer assembled in the first part of the article as a power source. (A list of all possible substitutions in the diagram is located at the end of this page.)
Rice. 3. Common ISP plug pinout.
The programming conductors should be connected to the programmer conductors of the same name. It is convenient to connect these conductors to the mating part of the connector of the existing programmer using a standard plug for installation on the IDC-10MS board (Fig. 3). The exact location of the pins on this plug must be checked with the existing programmer!
Rice. 4. Top of the board.
Let's arrange all the parts on the future debugging board in accordance with the diagram. First, one by one, install the parts into the holes, cut off the excess length of the element leads with side cutters or wire cutters, and solder them. After this, you can make connections with wires. In that part of the circuit that will not change in the future, it is better to make connections from the bottom side of the board. The socket (also called “crib”) for the microcontroller can be soldered empty, and then the microcontroller can be inserted into it. In this case, you must not forget about the “key” of the socket and the microcontroller itself. In our circuit, for example, the quartz connections, connections to the programmer and the microcontroller connection to power will not change in the future. And we will most likely change the connections to the LEDs for different experiments.
Rice. 5. Bottom of the board.
It is best to take power conductors of some other color; For the positive wire you can use red, for the negative wire - blue or black. When routing the connecting conductors on the back side of the board, do not forget about the “mirroring”!
You can install the LEDs evenly as follows: thread a small strip of cardboard between the leads of the LEDs, install them in the holes of the board, cut off the excess length of the leads on the reverse side and solder them. After soldering the legs, the strip of cardboard can be removed, Fig. 6.
Rice. 6. Installation of LEDs.
Before turning it on, let’s once again check the correctness of the connections, and most importantly, the correct wiring of the power conductors to the microcontroller!
If, when the power is connected, the green signal LED in the stabilizer circuit lights up and nothing heats up, then the circuit is assembled correctly.
Now we can congratulate ourselves, we have just received a real development board assembled with our own hands!
Let's immediately load the simplest program for blinking LEDs into the microcontroller: . After loading the firmware into the microcontroller, the LEDs will begin to blink alternately. The glow and pause time will be approximately one second:
Video 1. Test firmware operation.
Such a debug board can be used not only for testing designs or software algorithms. Sometimes electronic circuits assembled on breadboards are used even by professional electronics engineers to build complete devices.
In the future, I will give several examples of how, based on this debugging board, you can assemble a simple lighting effects machine, a musical bell, a timer with LED indication, and even the main module of a simple robot.
Possible replacements in the circuit with the ATmega8 microcontroller Fig. 2:
- Quartz resonator Q1 can be used at frequencies from 2 to 8 Megahertz. The test firmware (flashing LEDs) will run slower or faster.
- Capacitors C1 and C2 must have the same capacitance from 18 pF to 27 pF.
- The capacitance of capacitors C3 and C4 can be from 0.01 µF to 0.5 µF.
- Resistor R1 can be replaced with another one with a resistance of 10 to 50 kOhm.
- Current limiting resistors R2-R5 can have a resistance from 680 Ohms to 1 kOhm.
- LED1 -LED4 can be of any color and size.
- The main microcontroller may have the following designations: ATmega8L -8PU, ATmega8 -16PU. The main thing is that it is in a DIP or PDIP package.
Additions:
- ZIP: Test firmware for flashing LEDs.
- URL: .
Brave and Successful Experiments!!!
Usually, even before the final version of the device is assembled, it is debugged. Bugs in the program are caught, part values are selected, etc. For convenience, debug boards are used. The development board usually contains various buttons, indicators, interface converters and a bunch of other things. A lot depends on the needs of the developer. Some will need Ethernet with USB, while others will need regular RS-232 with several LEDs and a couple of buttons for the eyes. This is already the second version of my debug board. The first one was not bad, but still there were a small number of little things that I did not take into account. In this debug board, I tried to take into account everything that a developer of devices based on AVR microcontrollers most often needs.
What's on this board
- 8 LEDs with current limiting resistors. There is no point in making more than eight pieces, and less because... Connect them immediately using one eight-wire cable to the controller port. Very convenient in my opinion
- Linear stabilizer providing the board with 5 volts. Stands on the radiator for every fireman. It heats up noticeably.
- DC-DC converter at 3.3 volts. Some microcircuits are powered by 3.3 volts, and this stabilizer is intended for them. By the way, the entire board can be powered from this voltage at once; you just need to move the jumper to the desired position.
- RS-232 converter<->TTL. No comments needed. Why not USB? I just stupidly ran out of ports :-)
- Generator for 74HC00. Just in case the fuses are suddenly sewn crookedly. This is a rare occurrence for me, but I decided to add it just in case. Generates a square wave with a frequency of about 2 MHz.
- R-2R DAC. Disposable item i.e. played and abandoned. I put it on the board purely for fun because... there was an empty space left.
- Pair of N-channel mosfets. You never know, suddenly you have to control something powerful. For example, some kind of engine. So let them be.
- 4 resistor dividers. Necessary for pairing 3.3 volt logic with 5 volt logic.
- ZIF socket. Thanks to it, you can easily install any controller in a deep housing. From an eight-legged teen to a 40-legged mega.
- LED seven-segment four-digit indicator. A current-limiting resistor is screwed to each segment, and all segments are interconnected.
- 28-pin socket. Plug in a second controller or something. Might come in handy.
- 8 buttons with controlled pull-up. No buttons anywhere. The main means of entering data into the microcontroller. The pull-up can be disabled individually for each button using a group of switches. The buttons can be pulled up both to the power plus and to the minus.
- Beeper with a transistor switch. Sometimes you need to squeak.
- Variable resistor. Sometimes needed for debugging programs working with ADCs
- Harness for I2C. Two regular 4.7k resistors. Can be disconnected/connected using jumpers.
- Reference voltage source on the TL431 it produces five volts. Connects to the controller with a jumper.
- Two integrating chains for debugging PWM.
- Connector for debugging projects with a USB software interface. In addition to the connector itself, there is also the necessary binding.
- Connector for SD memory card.
Almost all parts are SMD. This is what the back of the board looks like:
True, the flux is not completely washed off. And I don’t care, I’m tired of washing it. A variable resistor and clock quartz are not soldered onto the board. They were mysteriously lost somewhere during the assembly of the board.
Board power
The board can be powered from an external power source producing a voltage of approximately 12 volts. Of course, you can do more, but the linear stabilizer will heat up more. 5 volts can also be obtained from the programmer, jtag debugger and USB port. If 3.3 volt power is required, a DC-DC converter can be used. The desired source is selected using a special jumper.
Connectors on the board
The jtag and isp connectors are my own and most likely are not compatible with other debuggers and programmers. But I think it won’t be difficult to remake them as you need.
Scheme and signet
No jambs in the wiring have been noticed so far. But that doesn't mean they don't exist! Therefore, it is better to check everything again. The circuit diagram for this board was not drawn up for one simple reason: it consists of bricks independent from each other (DC-DC converter, level converter, etc.) the diagrams of which can be found on my website and on the Internet in general. and even more so, all the denominations are signed on the signet itself. If I can overcome laziness this weekend, I’ll draw :-)
To make the board you will need:
Indication
Connectors and sockets
| Name | Quantity pcs. |
| SCZP-40 ZIF socket with zero force | 1 |
| SCS-28 Socket for DIP-28 chip | 1 |
| 104B-TAA0-R SD/MMC card holder | 1 |
| USBB-1J USB socket on board corner type B | 1 |
| DRB-9MA D-SUB connector 9 pins, board plug angled | 1 |
| Power connector 7-0088 per board, 5.5 x 2.5 mm | 1 |
| Pins pls. Sold immediately in the form of a series of pins. They need to be broken and soldered. They are easy to break. I counted 324 pins. It is better to take 350 pieces with a reserve. | 324 |
Microcircuits
Buttons and switches
Resistors SMD 1206
| Name | Quantity pcs. |
| 220 Ohm | 19 |
| 68 ohm | 2 |
| 0 ohm | 20 |
| 1 ohm | 3 |
| 4.7 kOhm | 3 |
| 10 kOhm | 6 |
| 2.2 kOhm | 3 |
| 100 Ohm | 4 |
| 820 Ohm | 1 |
| 1 kOhm | 11 |
| 2 kOhm | 11 |
| 1.5 kOhm | 5 |
| 3.3 kOhm | 1 |
