(urgent - please help!) 40106 maximum frequency?

[egasimus]

What's the maximum frequency a 40106 (HCF40106, I think) can put out as a square wave? I'm in dire need of a clock source for an Atmel ATtiny26 MCU, and I can't buy anything over the weekend, but I might have one of these laying around. So is the 40106 suitable for this?

[anchovie]

The datasheet says that R has to be between 50k and 1M and C has to be between 100pF and 1uF, and that with these value ranges the waveform period will be between 2us and 0.4s. Therefore the highest frequency that can be achieved is 500kHz.

[R.G.]

ATTiny26 doesn't have an internal clock source??

[cloudscapes]

I've gotten between 1.6 and 2mhz with that one (I was trying to achieve the same thing). far too low.

what are you trying to accomplish with the AVR?

[egasimus]

Well, it's supposed to have one, and it's supposed to be selected by default, I guess. But, a while ago, a guy with much more experience with AVRs than me told me that it's not always like, and, sometimes, if a chip doesn't program, then it needs an external clock source. This made me doubt, and so I desoldered a 14.318MHz crystal from an old Riva TNT2 graphics card I once found crushed under a car, rummaged through my parts bin for two 22pf caps, and that didn't help me one bit.

About what I'm trying to accomplish... I'm trying to program it, for one thing. Blink a LED or something to see that it works. I tried using a NXP mbed dev board as a programmer, and I managed to read the device signature bytes, but couldn't enter programming mode. That was before I put the external oscillator.

The project itself is simple, at least as far as I care - a music box based on wavetable synthesis, with lots of assembly code I can't understand, and a file with the note data for the song you want it to play. I already made it once, with the help of the aforementioned guy who borrowed me his USB programmer. So I spent a good several hours tonight, too, alternating between trying to build a serial programmer and a couple other tasks... no luck.

[R.G.]

Well, it's supposed to have one, and it's supposed to be selected by default, I guess. But, a while ago, a guy with much more experience with AVRs than me told me that it's not always like, and, sometimes, if a chip doesn't program, then it needs an external clock source.

I suspect that there's a programming option or setup whatsit you haven't found yet. I've used the AT series several times with good results. It always takes a day or so to fight through the configuration and programming details for a new uC.

About what I'm trying to accomplish... I'm trying to program it, for one thing. Blink a LED or something to see that it works. I tried using a NXP mbed dev board as a programmer, and I managed to read the device signature bytes, but couldn't enter programming mode. That was before I put the external oscillator.

Good for you. I nearly always start with "blink the LED" to verify that I'm programming OK before going to a more complex level of programming. I simplifies further troubleshooting immensely to take the complex programming out of the equation.