Search found 14 matches

by mikikg
Tue Sep 19, 2017 10:06 pm
Forum: Postbag
Topic: FRAM FM24C256 from RAMTRON
Replies: 17
Views: 814

Re: FRAM FM24C256 from RAMTRON

Another interesting behaviour of mentioned Fujitsu FRAMs regards data signals from it's SO (Slave Output) pin. Probably this is applicable for other SPI devices but just to mention. I have an problem when connecting it's SO output pin to some longer SPI line (~25cm), longer mean that it have some la...
by mikikg
Sun Sep 17, 2017 10:40 am
Forum: Postbag
Topic: FRAM FM24C256 from RAMTRON
Replies: 17
Views: 814

Re: FRAM FM24C256 from RAMTRON

Also take an look on Fujitsu line of FRAMs: http://www.fujitsu.com/us/products/devices/semiconductor/memory/fram/lineup/index.html I have used SPI version MB85RS64 and I'm very satisfied how that works. Due some requirements in my application I have to test it's endurance in real usage scenario, I h...
by mikikg
Sun Sep 17, 2017 6:59 am
Forum: Ideas & suggestions
Topic: USART Framing error flag | Improvements
Replies: 2
Views: 273

Re: USART Framing error flag | Improvements

Another improvement also regards USART. I don't know does it used in current library, but this option will save you time and simplify program. When receiving data via USART, it is helpful to enable IDLE interrupt which will be activated by HW if on RX line there is no more data to receive longer tha...
by mikikg
Sun Sep 17, 2017 6:42 am
Forum: Ideas & suggestions
Topic: USART Framing error flag | Improvements
Replies: 2
Views: 273

USART Framing error flag | Improvements

Hi there, as I didn't find any topic regarding USART Framing Error, here is one suggestion for future release of USART library. Problem: In some applications it is possible to have undefined state (not defined by external pull up/down resistor) during reset on USART TX pins. This can cause that afte...
by mikikg
Sat May 06, 2017 5:58 am
Forum: Libraries & Hardware
Topic: QEI 32bit for STM32F103C8
Replies: 6
Views: 923

Re: QEI 32bit for STM32F103C8

By "equivalent" I mean functional same code but written on some other way to get faster execution. How I can access directly TIM2 registers without Arduino abstraction layer? All other code in my program are OK but this single ISR function must be as fast as possible. Handling Z (Index) input is req...
by mikikg
Fri May 05, 2017 5:01 pm
Forum: Libraries & Hardware
Topic: QEI 32bit for STM32F103C8
Replies: 6
Views: 923

Re: QEI 32bit for STM32F103C8

Hi again, what is the fastest possible equivalent code for this function for TIM2 methods: void z_idx_isr_func() { timer.setCount(0); if (timer.getDirection()) { ints--; } else { ints++; } } I need to handle Encoder Z input via ISR and need to execute this function before I get next pulse from encod...
by mikikg
Sat Mar 11, 2017 10:36 pm
Forum: Projects
Topic: Signal Generator Using DDS
Replies: 10
Views: 3631

Re: Signal Generator Using DDS

Just for comparison, take an look on those two screen shots of AD9850 module: AD9850-20MHz.png AD9850-30MHz.png As you can see, sinusoidal signal is not perfect, you can obviously see quantization steps in time, and just imagine how some digital logic will work with such distorted signal at input! O...
by mikikg
Sat Mar 11, 2017 9:45 pm
Forum: Projects
Topic: Signal Generator Using DDS
Replies: 10
Views: 3631

Re: Signal Generator Using DDS

At least for SDRs based on quadrature de/modulators it is better choice to use oscillators with square wave output, that will produce much precise timing required for /4 divider. Sinusoidal wave in this case will have some drawbacks because we mix analog and digital signal and input stage of divider...
by mikikg
Fri Mar 10, 2017 3:22 pm
Forum: Projects
Topic: Signal Generator Using DDS
Replies: 10
Views: 3631

Re: Signal Generator Using DDS

Here is one useful screen shot which show frequency response of AD9850 module: DS2_QuickPrint1-2.png Si5351 is very very interesting small device, I build one SDR receiver with it and standalone VFO version both controlled via USB: http://yu3ma.net/wp/?p=496 http://yu3ma.net/wp/?p=794 Both construct...
by mikikg
Thu Mar 09, 2017 4:55 pm
Forum: Libraries & Hardware
Topic: QEI 32bit for STM32F103C8
Replies: 6
Views: 923

Re: QEI 32bit for STM32F103C8

I found one example in ~/Documents/Arduino/hardware/Arduino_STM32/examples/Sensors/HardTimerAsEncoder/HardTimerAsEncoder.ino In general this work. I have one practical question, what to do with "Index" input, I see in code that this input is not handled, and on other side I notice that losing steps ...