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Asynchronous events without interrupts?
The project I'm currently working on uses an ATmega168, with a main loop that runs at 60 Hz. About 3/4 of a loop iteration is spent refreshing a display. The display output...
Friday, 11 December 2009 - 21:02
printf() with simulavr?
I'm using simulavr 0.1.2.6. Is there a way to call printf() (or any other write to stdout) in my AVR program, and have the resulting strings show up in my terminal? I think it's...
Wednesday, 5 August 2009 - 23:26
Decimal floating point
Is there a decimal floating point library for 8-bit AVRs? I read that decimal support is buried somewhere in GCC 4, but I have no idea how to use it or if it's even supported by...
Tuesday, 4 August 2009 - 02:17
Fast "is-nth-bit-set-in-long" code
I thought I'd share this since it seemed like quite a novel optimization. Let's say you have a uint32_t bitfield and need to determine whether an arbitrary bit (*not* a constant)...
Thursday, 30 July 2009 - 23:57
AVR CPU exceptions?
This is something I'm curious about... Since the AVR architecture does not have privilege levels and CPU exceptions, what happens if you try to perform some kind of illegal...
Wednesday, 25 March 2009 - 21:49
AVR causing glitches on Vcc and GND
I'm building a mixed analog and digital circuit on a breadboard, using an AVR and a DAC. I have separate analog and digital ground planes connected in only one place, with plenty...
Tuesday, 17 March 2009 - 19:27
Shifting slower than multiplication?
Since a left shift on the AVR takes one clock cycle per bit, and multiplications take two cycles, isn't it faster in some cases to use a single multiply by a power of two instead...
Thursday, 12 March 2009 - 21:21
Waiting for output compare match--while loop or interrupt?
I'm using an atmega168 clocked at 20MHz. I want to use Timer1 in CTC mode to wait for a period of time between 200 and 102400 nanoseconds. In other words, I won't use the...
Wednesday, 11 March 2009 - 22:19
Clocking external logic
My AVR is using a 20MHz crystal. In addition, I have some external 74HC191 counters that need to be clocked with a 10MHz square wave. Can I obtain a 10MHz, 0-5V square wave from...
Monday, 2 March 2009 - 21:38
PORTB and ISP
On the atmega168, PORTB pins 2 through 5 are used for in-system programming. Is it safe to use these pins as outputs? In other words, if I solder up a permanent circuit with PB2.....
Monday, 2 March 2009 - 20:22
555 polarity inverter circuits
I found a couple of schematics for voltage inverters using a 555 timer: http://www.ecelab.com/circuit-po... http://www.aaroncake.net/circuit... The first website says that the...
Wednesday, 18 February 2009 - 18:32
int_fast16_t?
Is there any difference between int16_t and int_fast16_t data types? In stdint.h I see that int_fast16_t is typedef'd to int16_t, which makes me think there's no difference. The...
Monday, 16 February 2009 - 19:57

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