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  1. Fish4Fun

    IRFP4332 250V Mosfet Rise & Fall Times

    I have some IRFP4332 mosfets, and I think they might be suitable for a one-off 90Vdc motor speed controller project, but none of the datasheets I can find specify td on/off or the tr/toff other than to say, The most recent datasheet I can find was published by International Rectifier in 2009...
  2. Fish4Fun

    DS18B20 AVR Math Trick

    I am not certain how the C libraries handle converting C to F ... hopefully not by using floating point libraries ... but here is a quick trick to get 1 decimal precision for a display with very little math routine overhead ... The Math: ((20.5C * 9)/5) + 32 = 68.9F or (20.5C * 1.8) + 32 =...
  3. Fish4Fun

    ATMEGA2560 .ORG Directives for ELPM and other Extended Pgm Memory Instructions

    I thought I would share this because I pulled out more than a little hair figuring it out ... Please NOTE: This concerns AVR Assembler Instructions, No Idea how it is handled in C. I am working on an Assembler program for the AT2560 that has several large tables, the code itself fits in...
  4. Fish4Fun

    Logic Gate Sanity Check

    I am trying to use a single uC i/o Pin To toggle a PWM output between two mosfets ... Easily done with 5 NAND gates, but I would like to achieve it with a single 74xxxx IC and the logic is killing me ;-) Here is the Logic I need: ; A | B | Out1 | Out2 | ;---|---|------|------| ; 1 | 1 | 1 |...
  5. Fish4Fun

    Two Wire Serial bit-bang Dyslexia

    My Dyslexia is killing me and I need some help .... I can't remember the relationship between time and left-right orientation in the timing diagram ... I know this seems ridiculous, but it is the world I live in. In an effort to make clear what I am asking here are the two most likely scenarios...
  6. Fish4Fun

    Back to Back Schottky Diodes

    I am designing//building a "heavy duty" amplifier for a sensored BLDC motor (referenced here https://www.electronicspoint.com/forums/threads/sensored-bldc-motor-question.292730/ ) and am trying to decide how "isolated" it needs to be from the control system ... So, I have been reading up on...
  7. Fish4Fun

    Sensored BLDC Motor Question ...

    So I ordered one of these: https://www.ebay.com/itm/4600W-6384-120KV-BLDC-Outrunner-Sensored-Brushless-Motor-For-Electric-Skateboard/164069170610?ssPageName=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649 I am attempting to build a driver for it, but I expected the sensors to have outputs like...
  8. Fish4Fun

    PAL 16R6APC .....

    Have a ton of work I really need to be doing, so I thought I would look through some of my "miscellaneous" IC Bins and see what forgotten treasures they might contain ... I vaguely remember reading about PALs sometime back in the last millennium .... they were going to replace "Standard"...
  9. Fish4Fun

    Low Power Embedded DC supply from 120Vac Mains

    For years, a recurring theme in my DIY projects has been a "cheap" DC supply from AC Mains .... and to that end Wall-Warts have generally been the answer ... But sometimes a Wall-Wart simply isn't a good answer .... Over the years I have spent many, MANY hours conjuring up cost effective DIY...
  10. Fish4Fun

    Simple Water Fill Circuit with Buffered On/Off

    Nothing complicated here, just a simple circuit to turn a liquid fill solenoid on/off depending on liquid level with an adjustable amount of buffering to minimize pump cycling .... While virtually any standard float switches will work, the current/voltage/power capabilities required are...
  11. Fish4Fun

    AVR-ASM Set/Clear Bit Routines

    Toggling bits is pretty straight forward with an 8-bit AVR with a priori knowledge of the the particular bit to be toggled, especially if the bit to be toggled is in the address range of $20 to $3F (Registers $00 to $1F) ... sbi PORTA, 0 ; 1 Set PORTA.0 cbi PORTA, 1 ; 1...
  12. Fish4Fun

    PT4115E LED Driver Efficency

    I am using a pair of PT4115E Drivers (Data Sheet: https://people.xiph.org/~xiphmont/thinkpad/PT4115E.pdf ) to drive two different arrays of LEDs.... The circuit is identical to the "Typical Application Circuit" with the addition of a 10uF Capacitor across the LED arrays ( to reduce ripple, as...
  13. Fish4Fun

    Zero Crossing Point Detector .....

    FYIW *** This is as much a thought experiment as it is a real-world problem .... *** Typical "Hobby" Oriented BLDC motors and even recent "Industrial" BLDC motors are designed and built to be driven using "sensorless" drivers .... Of course "sensorless" is a Red-Herring, the motors//drivers...
  14. Fish4Fun

    Benchtop PWM Generator

    I have bins full of projects in various states of completion because some number of hours/days/weeks/months into the project I "discovered" there was a better solution ready-made for some relatively trivial price or some Open Source project easily modified to suit my needs..... Yesterday I...
  15. Fish4Fun

    FSAM75sm60A Fault Protection Timing Circuit

    I am likely making this too hard, but a bit of help sure would be appreciated! I picked up some FSAM75sm60A "NOS" ICs off ebay a while back for cheap....and I thought I might design a test bed for one of them....I was trying to "rough in" some component values from the data sheet, and things...
  16. Fish4Fun

    Arduino Mega2560 & GRBL .....

    I am an absolute NooB with respect to the Arduino IDE and C programming, but I have been building projects using the AVR family of uControllers since the 90's.....of course, everything I have done has been in Assembler.....What I actually "need" I could have done in an afternoon writing ASM, but...
  17. Fish4Fun

    ATMEGA2560//Atmel Doccumentation Error?

    In the Data Sheet for the ATMEGA2560 the following code example is given to initialize a UART: Assembly Code Example(1) USART_Init: ; Set baud rate sts UBRRnH, r17 sts UBRRnL, r16 ldi r16, (1<<U2Xn) sts UCRnA, r16 ; Enable receiver and transmitter ldi r16, (1<<RXENn)|(1<<TXENn) sts UCSRnB,r16...
  18. Fish4Fun

    Stepper Motor Max RPM

    Fish4Fun submitted a new resource: Stepper Motor Max RPM **Theory** - Stepper Motor Max RPM **Theory** Read more about this resource...
  19. Fish4Fun

    Thoughts on LED Replacement of 8ft Tubes

    I have been working on an economical way to replace ~40 8ft F-Tube lighting fixtures for the past decade or so...with each advancement in LEDs I re-figure, recalculate and procrastinate.....The most recent cycle involves the 10W chips nominally 12V / 900mA with peak efficiency ~ 10.0V ~...
  20. Fish4Fun

    So I missed a memo.....or three or four

    I started playing with writing code for PCs back in the early 80's.....by the late 90's I had added AVR uControllers and a smattering of 8051 based uCs to my tool box....I still write/support some personal Apps for PCs in Visual Basic...I still write firmware for AVRs in ASM....I know I need to...
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