Guide: When I arrive in Tanabata, I will make a gift that belongs to her, unique, digital electric wave clock - eternal and precise. Interested in watching!
Hardware
MSP430F149, 4-bit 8 segment 0.8 inch Digital Tube, PCF8563T clock chip, electric wave clock module
use the software
IAR for 430 V5.3
Written in front:
After a long time, there is no posting, there are a lot of reasons, such as too busy, or too tired, or lazy, if I think I don't have any good ideas, there is no good idea, think of It's all already, I believe that not only the audience can't help but interested, I can't afford it. In fact, this DIY just hit the Tanabata Festival. Since there is this opportunity, there is also the material that can be used in the hand, it is better to force himself, make a gift that belongs to her, unique gift: Digital electric wave clock - Eternal precision Time.
When the decision was determined, it was already July 22, and the July 10 days from July 2, the 2nd day of the planing, the actual development cycle was only 8 days. Time is already very urgent at the beginning. According to my previous experience, I have been designing the circuit map at this time, but I decided to do an attempt and change this time, I am determined to spend the most spending the most time design appearance. After searching for a lot of similar profile products, I drew a colleague who gave me a sketch, let him take the time to help me with CAD to draw a 3D model map. After several discussion details, he realized the shape of the shell in the brain. I have seen this here, I have already guess what I have to do, I am right, I am going to deliver this 3D model to a 3D print shop. I also proposed the process requirements for surface polishing and spraying. When this task is completed, it is already on the afternoon of July 28. The remaining time will be handed over to a 3D print shop. Here, the outer casing portion is handed over to 3D printing, while the acrylic panel portion is given to a special acrylic cutting store. As long as the processing accuracy of each part can be guaranteed to be in 0.4mm, it is possible to assemble the halves.
Designed appearance drawing
hardware design
Although the time delivered to the 3D print shop is on the 28th, I have completed the schematic design in the afternoon of the 25th. In fact, the schematic is not complicated, and a single-chip drive drives 4-bit 8-segment common yin digital tube. I believe that most electrologically related majors that have not graduated, can be easily created. Here, because it is a common cathode, I used a lot of three-level tubes to do driver and position, in fact, I can use other integration ICs to achieve, but only time is nervous, I can only use my most familiar way. . Briefly describe the power supply from the 5V power adapter, after the AMS1117-3.3V voltage regulator, filter and decouplely paste the C-pole 9013 of the MSP430F149, the digital pipe of the digital tube, and the RTC clock chip PCF8563T. And the electric wave clock module. The power supply, single-chip microcomputer and digital tube driver have nothing special, I am focused on this electric wave clock module.
Schematic
Modern tutorial technology, a variety of, everyone is most familiar with the report before the 12th news broadcasts on TV, the newspaper started. The so-called timing is that the centering center is developed in various forms (broadcast, television, Internet, radio signal), etc., the precise time of the atom clock is picked up. In this way, there is actually a lot of timing techniques run in everyone's life, and GPS is a relatively low cost. Any GPS module outputs time data obtained from satellites, and the satellite's time source is also a starry atomic clock. However, GPS has a fatal weak point that is not working in the room, so time data cannot be output. Based on this, several developed countries in developed countries have built a medium wave broadcast type, and the time is completed through the form of wireless data broadcasting, and the medium wave can reach 2000km. Among them, the JJY Time Center in Japan and the BPC Time Center in Shangqiu, China, can receive signals in Wuhan in my city. However, it is impossible to indignantly, a state-level center-level center for the construction of the Chinese Academy of Sciences, the patent ownership of the product is in the private company of Xi'an, in the market, in addition to the Chinese code BPC electric wavelength product produced by their house, There is no other. Here I discussed more of this company and the government and research institutions such as a role, but it is because of patented monopoly, there is no other product on the market, and my most needed decoding module is even more found. However, I can't worry, I found a shop owner in a treasure last December, claiming to crack the decoding format of China's code BPC, and decoding the module in the shot. In order to protect the interests of all parties, I will not pay the store name and ID. After receiving the module, I have been tested. Under indoor conditions, you only need to align the module's antenna (Northern Shangqiu in Wuhan). After dozens of seconds, it can successfully obtain time, output data from serial port. .
The electric wave clock module (black winding is antenna)
After starting 3D printing on the 28th, my PCB size and positioning hole position have also been determined, and you can start designing the PCB file immediately. There is a schematic and rough design in front, the PCB design is easy to achieve, and PCB has been completed on the afternoon of the 29th. Because it is necessary to have completed before August 2, it is necessary to take the priority. I used a 24-hour proof, and the PCB will arrive on Thursday 31. Finally, only 1 day for the flexible and hardware combined.
software design
The design of the software part is actually simple and simple, and it is troublesome. Because I chose TI's MSP430 single-chip microcomputer, this single-chip has a characteristic that there is no open drain output mode, so when IIC in the face of the RTC chip, the pin like SDA is to output another situation to input, it is very trouble. The solution can only be changed to the output when the port mode is changed, and the port mode is changed to input when needed. Drive NXP PCF8563 this RTC I have achieved countless times in 51 and STM32, but this time the transplantation to 430 is quite a good job, the main problem is the card in the host (MSP430) to the slave (PCF8563) ) After initiating the read and write request, you can't get ACK. Friends who are familiar with IIC communications should know that ACK is the basis for ensuring the success of IIC communication. After 1 day and 1 night debugging, I finally found that after the issue is issued, the SDA pin does not switch to the input mode before the ACK is coming, causing the ACK unable to pull the SDA pin, causing the ACK signal. . After this problem is solved, there is no problem with the following software debugging, the control of the digital tube and the number of time data from the electric wave clock module are very simple. Here I also used a timer interrupt, and the effect is a 1 second flashing of the colon in the middle of the digital tube, used to simulate the second, actually following the relationship.
Main program flow chart
Joint debugging
The PCB board arrived at noon on the 31st, while arriving at the same time, and 3D printing shell.
Used an afternoon, put the PCB welded to debug.
In the evening, I found that the SOT-23 packaged 9013 triode B and E poles actually painted. Now the revision has been too late. Only one way is to turn the triode 180 °, then put the lead like it, so welding , B and E exchange the location. To step up the cast, all the software functions are all achieved before 12 o'clock in the evening.
The trial is installed into the box, there is no fixed and bond, and it does not install the radio wave module.
The next day is No. 1 to the company, suddenly found that the size of the acrylic panel and the outer casing remains do not match, and some inspections are discovered that my colleagues gave the wrong data. I have a pit, I have to manually cut the acrylic panel, and I don't have a way to make up for it. Into the paint pen inside, used to face
Panel edges have a neat place
Overall unit
The overall assembly fee is a bit, because the thickness of the electric wave clock module and the antenna before, so it has been adjusted for a long time to find a position that will not be crowded together. Finally, the final assembly was completed.
startup screen
Display time 1
Display time 2
6, packaging box production
I have given her an SD / TF card reader before, but because there is no housing, a naked PCB is laughing for a long time. So this time I decided to design a box on the basis of the shell. All materials of the box: box, filling material EVA, the inner subelp cloth is all in a treasure. The packaging box is a 2nd morning. I have to go home at noon, so I will finish the meeting, and I will call to help me make the shell colleague to cut the velvet and filler. Finally, I was completed before 12 o'clock, I'm big!
Original box
Start to fill
Fill is completed, put the lined cloth
Put into, complete
Write behind:
In fact, this time DIY is produced, there are still many problems. Mainly because of the time rush, there is no one by one by one of the sizes of the panel and the outer casing. It is also because of the rush, the PCB package does not have enough inspections to be delivered. As for the program, because of the purpose of implementing the function first, there is no optimization, in the case of shaking, can see the digital disconnection. If there is time, I will reopeize a program, plus some external control functions, and even the battery and charging management. Of course, this is the later, in short, the specified content is completed before the specified time, and the self-evaluator is a qualified DIY.
After arriving at the 2nd afternoon, I gave her, it looked this time, she liked very much, immediately put it on the table. Hahaha, so happy!
Finally, there are two photos between work, and our hardware engineers.
Bamboo
About the Author
Jindian, Forum ID: POWERDRUY
The witnesses founded by the panel network forum, a very waterful technical house, very active at the beginning of the forum, published a lot of posts.
Love the hardware, love to collect the development board. Weibo Address: http://weibo.com/poWerdruy
Now focus on the research and development and promotion of intelligent transportation products.
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