3V <-> 5V Level shifter ?

Started by Martial Chateauvieux in comp.arch.embedded15 years ago 15 replies

Hi, I want to connect a GPS Smart antenna SAM LS from u-blox, to the UART of an atmega128 running under 5V. ...

Hi, I want to connect a GPS Smart antenna SAM LS from u-blox, to the UART of an atmega128 running under 5V. Unfortunately the GPS runs in 3V and has 3V compatible IOs. I set up a 3V regulator already for the power supply. Can someone explain how to build a level shifter from 3V to 5V with a transistor ? (How do I choose it, how to...


Want a chip to block AC contamination

Started by Johnson Liuis in comp.arch.embedded15 years ago 7 replies

I am a newbee in RF circuit design. I found sometimes the small AC components from input antenna ( < 1.5 GHz) can contaminate the DC Power...

I am a newbee in RF circuit design. I found sometimes the small AC components from input antenna ( < 1.5 GHz) can contaminate the DC Power supply (Vcc) without a proper protection. Vcc is used to feed the first stage amplifer. Of course I can use a traditional LC networks to block the AC components from Vcc. However, I hope somebody can recommend me a small IC chip which can do the same


flyback smps using lm2585-adj

Started by Anonymous in comp.arch.embedded15 years ago 9 replies

I may be somewhat off topic but i've ran into a mountain i cannot seem to get over regarding the hardware design of a switching mode...

I may be somewhat off topic but i've ran into a mountain i cannot seem to get over regarding the hardware design of a switching mode power supply. I'm using an LM2585-ADJ simple switcher chip from National in a non-isolated flyback configuration to generate 3 output voltages: 3.3, 15, and -15. The monitored (feedback) output, 3.3V, has a lot (1.3 V pk-pk) of transient noise at and only at...


can imperfect power reset damage flash programmable HC08 ?

Started by Judges1318 in comp.arch.embedded14 years ago 1 reply

Dear all, Can an imperfect power off reset, with the power supply going down to 0.5 V instead of required 0.1 V, damage flash programmable...

Dear all, Can an imperfect power off reset, with the power supply going down to 0.5 V instead of required 0.1 V, damage flash programmable HC08 chips? I have made a board with a micro and a RS232 line driver amongst other things, and I have been using Metrowerks to download the code. It worked ok for some time, it went to a few dozens of programming/debugging cycles, say 30, and the...


current limiting PS and PIC

Started by Anchor in comp.arch.embedded14 years ago 2 replies

I am looking to design a current limited, 2-6A, power supply controlled by a PIC. Consumer electronic "smart microprocessor" battery...

I am looking to design a current limited, 2-6A, power supply controlled by a PIC. Consumer electronic "smart microprocessor" battery chargers seem to know how to regulate the current. Any thoughts?


Battery Backed external power supply

Started by Anonymous in comp.arch.embedded14 years ago 3 replies

We have a small unit which has a external power supply of 7V. This unit draws around 100mA. We have been asked to supply some sort of...

We have a small unit which has a external power supply of 7V. This unit draws around 100mA. We have been asked to supply some sort of battery backup for it. There is no ups to hand so what we are looking for is a DC small DC supply 7 to 15V which can power the unit from the mains and keep powering the unit for around 2 hours on power fail. This could be a external battery that connects in lin...


Quick question, how do I supply +-5V?

Started by Frank in comp.arch.embedded14 years ago 28 replies

I have a large board which asks for three power supplies, +3V, +3.3V and +-5V. First two can be easily satisfied with two HP power supplies...

I have a large board which asks for three power supplies, +3V, +3.3V and +-5V. First two can be easily satisfied with two HP power supplies (each has its own GND pin also). Regarding +-5V, can I replace with an HP power supply set to 10V, -5V pin connect to HP's ground and +5V to power?


HE-104 AC p/s

Started by kevincw01 in comp.arch.embedded14 years ago 3 replies

Hi, I'm building a pc/104 PC as a side project for fun. I purchased a pc/104 board as well as the he-104 12v vehicle power...

Hi, I'm building a pc/104 PC as a side project for fun. I purchased a pc/104 board as well as the he-104 12v vehicle power supply (http://engineering.tri-m.com/products/power/he104.htm). The system will enventually reside in a car with 12v power but during development I need to provide the 12v DC to the he-104 in my house. I'm thinking I can just go pick up a 12v AC adapter from radio shac...


ADC/DAC for 50-400Hz 3-phase?

Started by Guy Macon in comp.arch.embedded14 years ago 9 replies

I am doing some preliminary "back of the envelope" design work on a high-end split phase / three phase 50 Hz. to 400 Hz. AC power supply...

I am doing some preliminary "back of the envelope" design work on a high-end split phase / three phase 50 Hz. to 400 Hz. AC power supply & analyzer. Advice/comments/ridicule/brickbats welcome... Generating the 2 or 3 phases is straightforward, but monitoring the current and voltage is a bit more tricky -- especially when monitoring the far end of a transformer, line filter, or pow...


5 volt supply straight from 240v AC mains

Started by techie_alison in comp.arch.embedded14 years ago 34 replies

Hi, Please may I ask what the arrangement is when you see a single LED powered straight off of a mains power supply without any transformers...

Hi, Please may I ask what the arrangement is when you see a single LED powered straight off of a mains power supply without any transformers or switch mode circuitry? In other words, totally uninsulated or regulated. I have an old computer with an external hard disk which needs about 30 seconds to spin-up before the computer. With a small timing circuit, 555, or using a PIC even (have ...


Dell D-series Power Supply

Started by Janka Vietzen in comp.arch.embedded13 years ago

may be this is a bit off topic here but I bought a 3 year old D-Series lattitude leasing laptop D600 in Ebay. My old notebook had a 2 pin...

may be this is a bit off topic here but I bought a 3 year old D-Series lattitude leasing laptop D600 in Ebay. My old notebook had a 2 pin power connector and the switching supply worked down to 12 Volt. Only battery charging was disabled if power supply was not 18 Volt. From this reason I always used a direct 12V supply in my car without step up converter. I tried to do the same with my D-...


Signs of bad IC?

Started by cars...@gmail.com in comp.arch.embedded13 years ago 4 replies

Hey all, I'm in a microcomputer hw/sw class where we are building a microprocessor board using an 8088. I wire wrapped the clock circuit and...

Hey all, I'm in a microcomputer hw/sw class where we are building a microprocessor board using an 8088. I wire wrapped the clock circuit and the reset circuit before testing it with the 8088 in its socket, and all seemed to be fine (voltage tests, and frequency on the clock). When I put the 8088 in its socket I was getting a short between VCC and Ground on the power supply. When I remove...


temperature / voltage sensor recomendation?

Started by Adib Taraben in comp.arch.embedded13 years ago 1 reply

Hello, In my next uC design I need to check periodically battery and uC temperature and battery and power-supply voltage. I do not have a...

Hello, In my next uC design I need to check periodically battery and uC temperature and battery and power-supply voltage. I do not have a native I2C nor 1Wire on the uC wherever CAN or SPI or some IOs are available. What I prefer would be a kind of simple 2wire interface to some small and handy sensors. Some recommendations ? Are there some don't use sensors? Thx, theAdib. -...


driving an LED with a 7406 question

Started by panfilero in comp.arch.embedded13 years ago 58 replies

Hello, I have a question about driving an LED with a 7406. Basically I have an MCU going into a 7406 inverter going into an LED going to...

Hello, I have a question about driving an LED with a 7406. Basically I have an MCU going into a 7406 inverter going into an LED going to a resistor R and that going to a 5 V power supply. All in series, and I'm trying to find the value for R that would make this thing work.... here's a sketch of what I'm talking about (this is my first time skecthing on notepad) ...


wavecom gr64 blues

Started by adams10 in comp.arch.embedded13 years ago

Having problems with gr64 transition from gr47 I design primary cell battery powered equipment large volume and have had nothing but trouble...

Having problems with gr64 transition from gr47 I design primary cell battery powered equipment large volume and have had nothing but trouble moving to the wavecom gr64 below have been my issues 1) Power supply -Power requirements are much more challenging than gr47 I no it's class10 not class8 but even so after changing in firmware still is not as easy as gr47 had to do mental gymnastics to ove...


Looking for a board with following caracteristics...

Started by Guillaume Chevillot in comp.arch.embedded13 years ago 4 replies

Hi, I'm looking for an embedded board with these minimum caracteristics : - maximum size 150x150mm - low consumption : less than 1A with a...

Hi, I'm looking for an embedded board with these minimum caracteristics : - maximum size 150x150mm - low consumption : less than 1A with a 5-7V power supply - one (or more) i2C link - a free RTOS running on with free tools (to compile, download, ...) eCos would be the better. - one usable (not only for programming) RS232 link with a DB9 connector A do not need a powerfull CPU, ...


Alternative to AVR Butterfly?

Started by mc in comp.arch.embedded13 years ago 43 replies

Does anybody make a cheap single-board computer with microcontroller and LCD display, like an AVR Butterfly except that the LCD is easy to use? ...

Does anybody make a cheap single-board computer with microcontroller and LCD display, like an AVR Butterfly except that the LCD is easy to use? The Butterfly's LCD is segment-addressable and if you want digits or characters, you have to create them yourself. A 5.0-volt power supply (instead of the Butterfly's 3 V) would also be handy since I have to have 5.0 V for the equipment to whic...


Not able to see umon prompt

Started by SN in comp.arch.embedded13 years ago

Hi, I have connected the target board properly. It has a serial cable connection, one Ethernet connection and power supply. The steps I...

Hi, I have connected the target board properly. It has a serial cable connection, one Ethernet connection and power supply. The steps I am following are like I am opening one terminal and running the command minicom -dfl. But it is not showing umon prompt. Initially when I started working with Target I have seen umon prompt once. But now I am not able to get it. I am very new to Linux, ca...


Disable the RTC?

Started by Vladimir Vassilevsky in comp.arch.embedded12 years ago 2 replies

Hello All, There is a board with BlackFin BF-537 DSP. We are not using the RTC which is built in BlackFin. I want to disable the RTC to avoid...

Hello All, There is a board with BlackFin BF-537 DSP. We are not using the RTC which is built in BlackFin. I want to disable the RTC to avoid any unwanted activity. There is no way to disable the RTC by software. The RTC has the separate power supply input (VDDRTC), and the pins for connecting a 32k XTAL (RTXI and RTXO respectively). The datasheet says nothing on this matter. The customer ...


thin-client style case for micro-ATX?

Started by Grant Edwards in comp.arch.embedded12 years ago 2 replies

Has anybody run across a small thin-client style case for a micro-ATX motherboard? All it needs to hold is the motherboard and a slimline...

Has anybody run across a small thin-client style case for a micro-ATX motherboard? All it needs to hold is the motherboard and a slimline optical drive. No hard-drive, no power-supply, no expansion cards. All of the "normal" pc cases I can find are huge and include power supplies and drive bays I don't need/want. -- Grant Edwards grante Yow! They don't h...