A free series of textbooks on the subjects of electricity and electronics

A free series of textbooks on the subjects of electricity and electronics.

Ref. : http://openbookproject.net/

鉭聚合物電容VS鉭二氧化錳電容

找到一個介紹鉭聚合物電容與二氧化錳電容介紹的文章, 挺不錯的, 當參考ㄅㄟ.

A homemade receiver for GPS & GLONASS satellites

這世界上真正懂Global Positioning System (GPS) and the russian GLObal NAvigation Satellite System (GLONASS) 理論又能親手用最遠古的技術全DIY, 打造出來; 在台灣我沒見過; 恐怕也難有人懂所有打造接受器所需要的所有技術與知識. 現在返樸歸真應該要多多推行, 參考 Matjaz Vidmar 的業餘世界裡如何親手製作這套系統: 理論、類比電路、數位電路以及軟體. 這是相當令人著迷的. 太欣賞這樣的大師級人物了!

Ref. OpenSourceGPS   

RF & SENSOR Modules

1, Hope Microelectronics Co., Ltd.
2, Nordic Semiconductor ASA, former Nordic VLSI ASA

microSD Card Description and Pin Out

1, microSD Card Description and Pin Out
2, http://www.tayloredge.com/reference/Interface/SDPINOUT.pdf

RS-485

I've not surveyed more details on RS-485 specifications, but now I am studying ...hey hey..more fun.

Ref. :
1, Serial Programming/RS-485
2, Serial Port Central
3, RS422/485 Application Note
4, Measure & Control on-line 測控在線

Layout Guide Criteria

These days I am reviewing layout guides for keys parts about Spartan-6 FPGA Layout H/W platform, so the layout criteria about this projects can be listed up together. This phase is important that a real placement & route during layout house processing. Pheu, really learned a lot! jeje...

Fingerprint Sensor

I am searching those fingerprint sensors that I can use it by implementing my project before. The question is that I used a 256x256 grey scale sensor with bmp file captured before. This is not a new tech now. I just want to explore those software or digital signal inside of techs. Some issues I need to solve them before I implement it by linux program:
a) translate Matlab again into C++ codes
b) apply dsp tool kit especially fft and convolution to implement matlab codes
c) find a hardware platform for this basic dsp and also can accept directly digital format like CCIR-656 from fingerprint sensor
d) linux learning
e) etc

Polymeric Positive Temperature Coefficient device(PPTC, Resettable Fuse)

PPTC can protect against overcurrent faults in your circuit. So my question is how we can choose a PPTC device? What circuit's parameters in my design needed to determine first? And how to use those parameters to map manufacturer's catalogs. So there's a title of "Selection steps from the Catalog" which can be found in Fundamentals of PolySwitch Overcurrent and Overtemperature Devices. If you want to use PPTC in your USB circuit design, you can see "PTC Overcurrent Protection for Universal Serial Bus Circuit Designs" or "Meeting USB Overcurrent Protection Requirements" for help.

Vendor Ref.:

1, Hansor Polymer Technology Corp.

2, FUZETEC TECHNOLOGY CO., LTD. 

Hardware Book

Internet's largest free collection of connector pinouts and cable descriptions.

Viewing Schematic about XC6SLX45 Spartan-6 FPGA

hihi, i am viewing that an open schematic from here. So I sent a feedback on their schematics. Those pages have viewed about Audio/Ethernet/Misc./IR pages of its schematics. If you are a designer who wants to learn more on XC6SLX45 Spartan-6 FPGA, this site is designed and hosted by a French guy. May help you a lot of info on fpga techs. Also you can check here I contributed for more details.

Ethernet Reference Designs

Here have many reference design about Ethernet. I am checking Ethernet circuit. jeje

How can I import a white and black picture file into Silks_Cmp layer

I posted a message on Kicad list to ask like as title mentioned. http://tech.groups.yahoo.com/group/kicad-users/message/6595
Hope can get someone feedback soon.

Electronic Circuits Database

Electronic Circuits Database

BatchPCB / Gerber knowledge / Open Circuits

I just found another PCB maker called BatchPCB. And Gerber knowledge in wiki.
An Open Circuits which collects a lot of open hardware parties.

avt2 RC1 reference board

I just posted this specifications on Qi wiki page.

FEATURES

* 336 MHz XBurst Jz4720 MIPS­compatible CPU

* display: 8­bit RGB / ITU 656/601 data format input of TFT display.

* dimension (mm): 94.5 x 65

* DRAM: 64MB Synchronous DRAM

* headphone jack (3.5 mm)

* SDHC microSD

* support 850mAh charge limited 4.2V  Li­ion battery

* 2GB NAND flash memory

* mini­USB: USB 2.0 High­Speed Device

* micro­AB USB: USB 1.1 Host

* serial console

* speaker and microphone

* 58 Keys

Is there Any Open TV Platform in the Near Future

As title, is there any open hardware platform about TV even LCD display in the near future? I was thinking this couple months ago...now the answer is EXSITING.

What's Equivalent Circuit and Paramenters of Crystal

Many digital circuit it needs external crystal for microprocessor. And usually the datasheet tells you its input & output capacitance. So how you choose a Xtal's with correct parameters? The following descriptions can give you a formula.
Equivalent Circuit and Paramenters:

Equivalent Series Resistance ( R1 ):

The resistance is motional resistance ( series ) in the equivalent electric circuit. 
Motional inductance ( L1 ):
The inductance is the motional inductance ( series ) in the equivalent electric circuit.
Motional Capacitance ( C1 ):
The capacitance is the motional capacitance ( series ) in the equivalent electric circuit.
Shunt Capacitance ( Co ):
Shunt ( parallel ) capacitance ( Co ) is the capacitance between the crystal terminals. It is defference in package, usually it is less than 7.0pF.
Load Capacitance ( CL ):
The load capacitance is the circuit equivalent capacitance looking the circuit system from the two wire leads of crystal. The operation frequency in the circuit is defined by load capacitance and crystal.

U1 : ASIC
Y1: CRYSTAL
C1C2: capacitor which is connected
CL = [(C1*C2)/(C1+C2)] + Cstray + CU1
Cstray : stray capacitance
CU1: IC’s input/output capacitance
Cstray and CU1 may varies from 2 to 6pF

How to Solder RXD/TXD/GND in Ben NanoNote

This article is for Ben NanoNote's wiki page, you can also check here to know all the info in Qi Hardware's wiki page.

Purposes
    One wants to solder [1] extension wires for Ben NanoNote’s serial console test points. Since the Ben has that 3 test points (RXD, TXD & GND), it originally works as TEST POINTs on temporarily experimental or measurable purpose NOT permanently extendable one. Its original trace layout doesn’t allow you to do this under improper soldering method or carelessness. But if you still want to use serial port for a long while, this article can give you some guide lines.
Product
    Ben NanoNote
Tool & Material
    Soldering Station with a suitable conical type of soldering tip [2]
    Soldering Wire 0.5Φ diameter [3]
    Wire-Wrapping Wire 30AWG [4]
    Multi-function wire stripper [5]
Frequent Failures When Soldering
    Condition a, Test points ( Pads ) are broken from pcb surface

    Condition b, Trace with Test Point is pull out

Figure 1

    With improper soldering method or carelessness, you probably get either both or one of them.
Knowledge about Soldering
     Since the iron soldering tool can easily let you join two metallic surfaces into one, you need to be careful about your soldering head temperature, how many seconds you use and how about your craftsmanship you have. Before you start to do the following steps, you can also check the physical theory a little bit or ask anyone possessed of senior soldering skills to help you.
     Through [1], you can see more soldering articles for your reference. Also you can check here [7] to know HOW TO SOLDER first.
STEPs
A . Soldering Accessories
     A 900M-T-1 size of soldering iron tip can be suitable for this process. You can choose a 1 or 3 marked tip as following figure. The marked 2 or 4 is not recommended.

Figure 2

Figure 3

    A 0.5mm diameter soldering wire is better.

Figure 4

    Also using a 30AWG of wire wrapping wire or equivalent AWG wire is recommended.

Figure 5

    Why choose so tiny diameter accessories? Please see next figure then you will easily realize. Unless you are an expertise with great craftsmanship in soldering field, I do really recommend that using them.

Figure 6

B. CLEAN up test points and wires

 The TXD (TP75) and RXD (TP74) are shown as below. Or see [8] [9] to understand their location. Clean up the surface of test point and wires first, you can just follow “ 2. SURFACE PREPARATION: CLEAN” instructions of [7] to do this step. Novices can make the mistake of overheating the parts as they try to force the solder to stick. This will usually result in irreversible damage and force you to scrap pads, trace or even BEN Nanonote.

                                               Figure 7                                          Figure 8
C. Tinning

     Contacts of both test points and wires must be tinned before attempt to solder. So now do tinning process on 3 test points and terminal of three wires as next figure as well. Some wire wrapping wire already have been tinned on its surface, you can just use a wire stripper to strip away the tip of the insulation to expose the copper wire within. Otherwise you must lightly coat it with solder. You must also tin the tip of the iron to help conduct heat to the components.

Figure 9

D. Applying Heat and Solder

     Before doing this step of real solder you can reference this video [10] to see how solder will be the better. “With the tinned soldering iron in hand, you are now ready to heat the components. Rest the iron tip on both the wire lead and the PCB. It will only take one or two seconds to heat the components up. Once you have heated up the wire and the circuit board, solder can be applied. Touch the tip of the strand of solder to the heated wire lead and the solder pad on the circuit board, but not to the tip of the iron. At this point, the solder will flow freely around the wire lead and the pad. Once the surface of the pad has been completely coated, you must stop adding solder and then, quickly remove the soldering iron. Do not move the newly formed joint for a few seconds until the solder cools down and becomes solid. Moving the joint at this point will cause a formation of a cold joint.”

Figure 10

E. Clean up

    Clean up again on all soldered area.
F. Fixed by glue or other adhesive tape
     Using any adhesive tape or glue is to protect wire-wrapping wires away from heavy extra-loading forced to bend wires, pull out test points or break trace shown as figure 1. If you’d prefer to use usb power rather than battery, you can just do like as following figure or use adhesive tape to protect those three soldered point.

Figure 11

Ref.

[1] http://en.wikipedia.org/wiki/Soldering
[2] http://www.sparkfun.com/commerce/product_info.php?products_id=619
[3] http://www.senju.com/pages/lead_free_wire.htm
[4] http://cgi.ebay.com/_W0QQcmdZViewItemQQitemZ120478983749
[5] http://www.sparkfun.com/commerce/product_info.php?products_id=8696
[6] http://www.tequipment.net/HakkoCSP30-1.html
[7] http://www.solderinguide.com/
[8] http://wiki.qi-hardware.com/wiki/Serial_console
[9] http://wiki.qi-hardware.com/wiki/File:Ben_nanonote_serial2.jpg
[10] http://vega.org.uk/video/programme/166
 Author: adam@qi-hardware.com

Experiment of Ben NanoNote's Charge Cycle

I just edited this at Qi Hardware wiki. So you can also see this article here.

Purpose of Experiment 
    To understand that how does Ben NanoNote’s charge cycle work.

Test Product
    BEN NanoNote

Equipments
    Agilent 34401A Multimeter
    CHY 48R Multimeter

Methods of Connection
    Current connection:

Figure 1

Schematic

Figure 2

State Diagram of a Typical Charge Cycle

Figure 3

Study System Voltage Specification

Before this experiment, let’s see how Ben’s design and how to choose low voltage detector first. Because the Ben has jz4720 VDDIO voltage (2.97~3.63V) see page 24 of datasheet [1], the NANAD FLASH K9GAG08U0M has Vcc range (2.7~3.6V), also SDRAM P3V56S40ETP has VDD range (3.0~3.6V). So a low voltage detector circuit that can shut down the cpu jz4720 when monitors Battery’s voltage goes down -VDET (2.94~3.06V) detected by BL8506-30NRM, and the Battery has a over-discharge protect voltage 2.25V.

Figure 4

Through figure 4, we can easily know the best working power voltage for ben should be between upper limited 3.6V of SDRAM and lower limited 3.0V of SDRAM. That’s their intersection. Of course if there’s an sdram with widely working voltage like nand flash at lower 2.7V. That would be good to lengthen discharging time. But then the intersection becomes 2.97V caused by cpu. Since battery cell has overdischarge protect voltage 2.25V, strongly recommended that the software should be possessed of a detector of monitoring battery voltage under 3.0 voltages to make sure sdram can work normally. That’s the reason why ben has a low voltage detector BL8506-30NRM [3] which is based on 3.0±0.06 V detection precision ±2%.

Charge Status Indicator (CHRG), pin1 of SE9016
From its datasheet [2], this pin can output three status: strong pull down(~ 10mA), weak pull down (~20uA) and high impedance. So D3 LED can be as indicator shown if charging or not.

Experimental Data
From SE9016 datasheet [2], when BEN is on Power ON mode (Display On) , PW_ON_N is low; so RPROG = R15 = 10KΩ, from Data collection, IBAT = (VPROG / RPROG ) * 1100, then we can calculate VPROG inversely from measured IBAT.
Before measurement, make sure that the battery is above 3.06V, otherwise the low voltage detects will tell s/w to shut down cpu and will enter POWER OFF mode. This experiment will split into two modes to measure different charge current.

Case a: POWER ON mode, PW_ON_N is low, Display ON, Slow charging
Case b: POWR OFF mode, PW_ON_N is high, Display OFF, Fast charging
We firstly let BEN entered into POWER ON mode to keep the RPROG equaled to 10KΩ, not 2 KΩ. (if enters POWER OFF mode, the high PW_ON_N will let Q3 TM2302FN turned on then RPROG is R14//R15. see figure 2). From the measured data [4] or figure 5 and 6. The data is a result that starts from 3.6V battery and charges it until ascending theoretically preset 4.2V charge voltage with ±1% accuracy thus 4.158V. Experimentally a 4.145V measured. When the bat pin approaches the final float voltage (4.2V), the SE9016 enters constant-voltage mode and the charge current begins to decrease. We can realize it needs 16.8 hrs from 3.6V to 4.2V.

Figure 5

Figure 6

There’s a voltage called “overdischarge protect/preventing voltage” for lithium-based battery. After measured Ben’s descendant voltage during its discharging, a 2.3V measured then battery inside turn off its output voltage to 0V. This is within its specification 2.25~2.35V. So can let Ben’s SE9016 acted as following figure.

Figure 7

Once VBAT > 2.8V and VPROG > 100mV, SE9016 charges as next figure which is stated in CC/CV mode.

Figure 8

Now let Ben entered to POWER OFF mode to keep the RPROG equaled to 2 KΩ. (R14//R15. see figure 2). From the measured data [4] or figure 9 and 10. The data is a result that starts from 3.2V battery and charges it until ascending preset 4.2V charge voltage with ±1% accuracy thus 4.158V. Experimentally a 4.135V measured. It needs 2.68 hrs from 3.2V to 4.135V. Afterwards, SE9016 enters constant-voltage (CV) mode and the current begins to decrease. The plot of figure 7 & 8 doesn’t include data of CV mode.

Figure 9

Figure 10

The standby mode of SE9016 didn’t experiment. Also see figure 8 in blue flow. To manually restart a charge cycle when in standby mode, the input voltage ( usb power ) must be removed and reapplied or the charger must be shut down and restarted using the PROG pin.

This result of experiment may be based on unique battery applied and referenced. You can also find this standard battery technology in many other devices. Ben batteries share the characteristics common to lithium-based technology in other devices. Like other rechargeable batteries, these batteries may eventually require replacement.

[1]http://downloads.qi-hardware.com/hardware/qi_avt2/v1.0/datasheet/U1~Jz4720_ds.pdf
[2]http://downloads.qi-hardware.com/hardware/qi_avt2/v1.0/datasheet/U5~SE9016.pdf
[3]http://downloads.qi-hardware.com/hardware/qi_avt2/v1.0/datasheet/U7~BL8506-30NRM.pdf
[4]http://downloads.qi-hardware.com/hardware/qi_lb60/report/charge_cycle/data.ods
[5]http://www.mpoweruk.com/chargers.htm#rates
[6]鋰電池的守護神---鋰電池保護IC的重要性

Author: mailto:adam@qi-hardware.com