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How would you setup the interrupts for this on the mega4809
This is for my multiplexed quad 5x7 display.  The device will be a SPI slave and allow daisy chaining the display so it will have its MISO connected to the next displays MOSI...
Monday, 9 September 2019 - 23:44
Any tips for labeling pins with #define
My tried a true method for the mega series was this:   #define PIEZO_PORT     PORTB #define PIEZO_POS_PIN    0 #define PIEZO_NEG_PIN ...
Wednesday, 4 September 2019 - 01:34
Pin current consistency / atmega 4809
I've got a breadboard up and running with an adapter that uses four LTP-305G displays, each is 5x7, so this is 20 columns by 7 rows.   Using some dual logic level mosfets (...
Thursday, 29 August 2019 - 22:42
mega1284 tqfp capacitor on all 4 vcc/gnd pins?
This project has very little power use from the AVR - nearly everything is high impedance except maybe one LED which will be less than 5mA.  Does it really need a bypass cap...
Thursday, 22 August 2019 - 03:19
Producing an opposite signal from output compare...
I want to drive a piezo and there are two ways.  Maximum volume comes alternating both signals at the same time like this:       DDRD|=_BV(6) | _BV(7);...
Sunday, 18 August 2019 - 03:28
Would you guys use the shutdown feature of this?
I'm making a floppy drive emulator for the Epson PX-8 CP/M computer.  It is basically an atmega1284 + hcms 8 char LED display + microsd socket + rs232 transceiver + a couple...
Saturday, 17 August 2019 - 18:13
Best 3 pin order for custom UPDI connector...
For many years I've used what I call "inline ISP" which is basically just the 2x3 ISP connector put into a 1x6, still 100 mil.  It allows programming from either side of the...
Thursday, 15 August 2019 - 02:40
ISR Multiplexing strategy with brightness/gamma adjustment
My plan to support multiple brightness levels has been to run the ISR a multiple number of times faster.  For example, if I want 100 Hz refresh and have 8 rows, that would be...
Wednesday, 14 August 2019 - 22:56
324PB max gnd and vcc current...
The datasheet says 100mA max, but the 324P says 200mA max - 100mA seems pretty low.
Tuesday, 13 August 2019 - 02:32
microsd - how long do you wait before trying to access
I want to give the user enough time to make sure the card is seated - the socket I'm using seems especially touchy with the CD signal.  It switches it to ground or open and...
Monday, 29 July 2019 - 21:53
Using MSPIM for buffering
On a mega1284 last night I was using the regular SPI at clk/2 and because of no buffering there are gaps between bytes being transferred.  I suppose this is the nature of SPI...
Thursday, 25 July 2019 - 12:26
How would you configure the ADC for 2 cell low battery
Consider that the 2 cells could be alkaline or NiMH and that they will be fed to a boost regulator that pushes them up to 3.3V.  A fully fresh alkaline pair could also be 3....
Tuesday, 23 July 2019 - 02:48

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