AT91SAM7S oscillator?

Started by orc in comp.arch.embedded13 years ago 2 replies

I'm trying to figure out how the oscillator is working in the AT91SAM7S from Atmel. The data sheet lists that an up to 20 Mhz crystal can be...

I'm trying to figure out how the oscillator is working in the AT91SAM7S from Atmel. The data sheet lists that an up to 20 Mhz crystal can be connected and the summary says that the oscillator runs at up to 55 MHz - is the crystal frequency multiplied by 2.75 or what? The system I'm developing needs a 6.0MHz and a 5.12MHz oscillator - will it be configure the PCK0-2 outputs to these freq...


Oscillator cannot oscillator

Started by terry in comp.arch.embedded13 years ago 1 reply

Hi, I am going to interface a chip usbn9603 to the microcontroller. However, I find the 24MHz crystal cannot oscillate (with capacitors 15pF...

Hi, I am going to interface a chip usbn9603 to the microcontroller. However, I find the 24MHz crystal cannot oscillate (with capacitors 15pF and shunt resistor 1M Ohm). Why? I have checked the circuit for the whole day but cannot find the solution. Could anyone give me some hints why the oscillator cannot work. Thanks!


SiLabs C8051F34x and baud rate generation from internal oscillator

Started by Anonymous in comp.arch.embedded10 years ago 3 replies

I know that this IC is able to be used with its internal oscillator when it is used for a USB clock with clock recovery to make it work, however...

I know that this IC is able to be used with its internal oscillator when it is used for a USB clock with clock recovery to make it work, however can the internal oscillator be used for clocking the UARTS, I need one of the 2 of them to run as fast as it can! which I read is / 16 or 3Mhz... on receive. Anyone know the answer... very hard to dig this one up. Richard.


Digital Crystal Oscillator

Started by rickman in comp.arch.embedded7 years ago 69 replies

I've read the Green Arrays web page app note on using a pin to turn a crystal into an oscillator...

I've read the Green Arrays web page app note on using a pin to turn a crystal into an oscillator at http://www.greenarrays.com/home/documents/pub/AP002-OSC.html Although the work they did seems to work well enough, they stopped working on the project a long way short of having an actual oscillator. I've been trying to run a spice simulation to explore this concept and finding that an os...


More info about the Crystal Oscillator book...

Started by Tara in comp.arch.embedded13 years ago 2 replies

Based on some requested info from respondants, here is more about the proposed Crystal Oscillator book. The book will introduce the basic...

Based on some requested info from respondants, here is more about the proposed Crystal Oscillator book. The book will introduce the basic concepts of crystal oscillator theory, describe their operation, and explore their various applications. Special attention will be given to environmental and operational parameters (such as keeping the crystal inside a temperature-controlled "oven" for i...


Relation between crystal oscillator frequency and ppm

Started by ssubbarayan in comp.arch.embedded11 years ago 2 replies

Dear all, Sorry if this looks novice.I am not able to correlate the relation between crystal oscillator frequency and ppm? What does the...

Dear all, Sorry if this looks novice.I am not able to correlate the relation between crystal oscillator frequency and ppm? What does the following sentence mean? "When a voltage is applied to the VCXO varacitors, the 27 MHz center frequency can be adjusted by approximately +/-150ppm (+/-4050Hz). " We are offlate finding problems in the oscillator frequencies giving erroneous results in...


oscillator needed

Started by el_s...@yahoo.com in comp.arch.embedded10 years ago 2 replies

Hi - I need a 10.7 Mhz signal to debug an FM receiver kit I am putting together. I have a Z8 Encore microcontroller eval board I bought sometime...

Hi - I need a 10.7 Mhz signal to debug an FM receiver kit I am putting together. I have a Z8 Encore microcontroller eval board I bought sometime ago so I might be able to use the pwm signal from it, but otherwise I'll probably need to use some sort of crystal oscillator. Any suggestions for simple circuitry ? Thanks in advance,


nios II sratixII interrupt handling with uController

Started by Anonymous in comp.arch.embedded12 years ago 4 replies

hi all! I'm using NiosII with StratixII. i wanted to get interrupts from a micro controller of 7.393MHz Oscillator which generates half...

hi all! I'm using NiosII with StratixII. i wanted to get interrupts from a micro controller of 7.393MHz Oscillator which generates half the oscillator clock. Nios works at 50Mhz. so what modification i need to do on nios


Why should I (not) use an internal oscillator for 8-bit micros

Started by Schwob in comp.arch.embedded13 years ago 62 replies

Hi, for a low-cost design I need a small 8-bit microcontroller (1-2k Flash will do) and now the question is whether I need to plan for...

Hi, for a low-cost design I need a small 8-bit microcontroller (1-2k Flash will do) and now the question is whether I need to plan for an external resonator or an internal oscillator is good enough. My application will have to communicate through a serial interface to the outside world. I don't know yet if that's going to be a UART or SPI or I2C, could be different for some of our customer...


Source for small oscillator crystals

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

I am working on a project using an FT2232C. I am trying to find a source of small oscillator crystals. The smallest I have found so far is a...

I am working on a project using an FT2232C. I am trying to find a source of small oscillator crystals. The smallest I have found so far is a Citizen CS20 which is larger than the chip I am trying to use. Seems rather silly to build this nice smd board and then have this huge crystal nearly dwarfing the rest of my components.


GA144 one pin oscillator again

Started by Albert van der Horst in comp.arch.embedded5 years ago 11 replies

There has been debate on this forum about whether with the Green Arrays GA144 chip, it is possible to make a crystal oscillator attached to...

There has been debate on this forum about whether with the Green Arrays GA144 chip, it is possible to make a crystal oscillator attached to one pin and no further components. The inventor of the chip demonstrates a working example, at least for a resonator that has a lower Q. A high Q only makes it harder to start the oscillation, but the principle is the same. This is explained in a vid...


RTL8019AS clock question

Started by Matt in comp.arch.embedded11 years ago 3 replies

Hello all, The data sheet for the RTL8019AS is a bit vague about the clock requirments. After emailing realtek and waiting a week for a...

Hello all, The data sheet for the RTL8019AS is a bit vague about the clock requirments. After emailing realtek and waiting a week for a response they answered most of my questions (20MHz, 16pF load impedence,


One pin, one component oscillator with GA144

Started by Albert van der Horst in comp.arch.embedded5 years ago 6 replies

Chuck Moore has published the code to run an oscillator on one processor of a GA114 chip. It uses a single 10 Mhz resonator and no other...

Chuck Moore has published the code to run an oscillator on one processor of a GA114 chip. It uses a single 10 Mhz resonator and no other components hanging off one pin. This works in principle also with a crystal (which led to some controversy here), but it is harder to get started because of the enormous q-factor of a crystal. This hinges on submicrosecond switching between input and outp...


Small controller with good on-chip oscillator

Started by Oliver Betz in comp.arch.embedded5 years ago 16 replies

Hello All, any suggestions for small (e.g. TSSOP20) microcontrollers with a good on-chip oscillator? One of the best I found is the 9S08...

Hello All, any suggestions for small (e.g. TSSOP20) microcontrollers with a good on-chip oscillator? One of the best I found is the 9S08 with 1% max. drift in the 0..70?C range. The 9S08 would do the job but is at it's speed limit. I don't want to tolerate much more frequency deviation to keep a certain margin for the fast async serial communication. 5V operation and a decent A/D-Co...


wd-g-zx4120 gps module

Started by Anonymous in comp.arch.embedded10 years ago 6 replies

Has anyone experience with this module .. in the specs it says that it provides 1 pps (1 pulse per second) output .. but which pin this appears...

Has anyone experience with this module .. in the specs it says that it provides 1 pps (1 pulse per second) output .. but which pin this appears on is unclear from the data sheets ... I would like to build a gps disciplines oscillator and require the 1 pps output as a physical signal to do the oscillator disciplining Many thanks for any advice/experience pearce.sg at gmail.com


Atmega8-L at 8MHz internal oscíllator not stable?

Started by Antti in comp.arch.embedded5 years ago 8 replies

Hi I am not believing what I see, but I have a board where ATmega8L doesnt want to work with 8MHz internal oscillator setting - the datasheet...

Hi I am not believing what I see, but I have a board where ATmega8L doesnt want to work with 8MHz internal oscillator setting - the datasheet does not say its invalid setting, and I think I have used it before, but now this board only works at 4MHz or at 8MHz when the OSCCAL is written to lower value


Opinions about potential Crystal Oscillator book???

Started by Tara in comp.arch.embedded13 years ago 8 replies

Hi there, I work for a publishing company and an editor is proposing a book about crystal oscillators. I thought going to a user group forum...

Hi there, I work for a publishing company and an editor is proposing a book about crystal oscillators. I thought going to a user group forum would be a good way to get feedback on market desire for such a book. The book is organized so that it can be read cover to cover or used as a quick reference on specific crystal oscillator types. If asking for this feedback is against the rules...


MPLAB error message

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

Hi to all, I am running MPLAB software to a PIC16F877A microcontroller via a CCS ICD-S20 pod. After downloading the code I get a pop-up with...

Hi to all, I am running MPLAB software to a PIC16F877A microcontroller via a CCS ICD-S20 pod. After downloading the code I get a pop-up with the following error message: "Could not start the target. The target was not halted after reset. Check the target oscillator and MCLR." I am using a 20MHz crystal oscillator from EPSON (working fine). The MCLR circuit is an MCP120-4.5V pulled up ...


Oscillator and Corruption of Registers

Started by karthikbalaguru in comp.arch.embedded10 years ago 13 replies

Hi, I came across the below statement - "If the oscillator frequency falls below the minimum of a dynamic processor, then that processor may...

Hi, I came across the below statement - "If the oscillator frequency falls below the minimum of a dynamic processor, then that processor may suffer corruption of its registers. " How far is that statement true ? (I have not analysed the Registers in that condition. Did not happen to face that situation ). Regarding the above lines, I think, that when the Osciallator Frequency falls belo...


Radiated Emc ethernet problems

Started by Anonymous in comp.arch.embedded12 years ago 7 replies

I have just designed a prototype Arm 9 based board that uses a Davicom DM9161 ethernet chip operating in RM11 mode, basically it require...

I have just designed a prototype Arm 9 based board that uses a Davicom DM9161 ethernet chip operating in RM11 mode, basically it require a external 50MHz oscillator that feeds it and the MAC in the processor. The board has just failed EMC emissions at 50MHz and 100MHz which are due to the ethernet, disconnectioning but still running the 50MHz ethernet oscillator made it pass. We have the opti...