Hi BigEd,

Thanks. Yes. I read that indeed. I also have one such oscillator (1Mhz) in my 6502 prototype.
Since I am from a microcontroller background (where we just plug the crystal and two load capacitors to the XTAL pins), I was just curious about the oscillator circuits and their types. When we ...

Thanks for your inputs.
And interesting. I came to know that there exist ovens for crystals!

Hi Garth,

Thanks for your replies.
The data sheet will tell you if it's cut and trimmed to be the particular frequency in parallel- or series-resonant mode..
I "assumed" the same when reading through the primer.
But when I was reading some article online, from a company called ECS, I got this ...

Hello,
When reading the 6502 primer (clock generation topic), I had few generic doubts. Can anyone please clarify them?
1. In the primer, there is a mention about series and parallel resonant crystal. How do we identify one? is there any marking on the crystal? or it is just the connection we make ...

Thank you very much for taking time to explain it.

And thanks very much for seeding your Passion! Not many people do that.

So, if I understand correctly, all this extra circuit involving R1 to R4, D1, C1, Q1 and LED are just for the Plug and play purpose?
If you don't need plug and play of I2C (permanently connecting them to power) then this circuit can be avoided all together.

Thanks.

Well, thanks for the explanations. This clears up few things for me.
It's to be able to use PB7 for more things, in this case for a beeper and for turning I²C power on and off. As the third bullet point below the diagram says, you can use PB7 for something like a piezoelectric beeper
This is ...

Hello,

I was going through the 6502 Primer for I2C BITBANG circuit.
(I am not able to attach the circuit image here) its in the this link:
http://wilsonminesco.com/6502primer/potpourri.html#BITBANG_I2C

Here, can understand why he choses Bit0 for clock and Bit7 for Data. But I don't understand the ...

I think the problem I faced has nothing to do with Ben's videos. Because, I had a 8K rom instead of 32K ROM which Ben used. So, I had a couple of NC pins in the ROM. By mistake, I mirrored those connections to the RAM (Which is by the way 32K)

Thanks for your suggestions guys.

Apparently, I had a connection problem :roll:

Address line A13 of RAM chip was not connected to the bus.
Stack was working fine with this setup. But I guess the variables at address starting from 0x00 was not working fine.

I have a 32KB RAM chip by only 8KB ...

Thanks, I will try what you have suggested. But which "other thread" are you quoting here? can you please give a link?
Oh I'm sorry, I mixed you up with another user, my mistake!
No problem.
I tried your solution. But it does not work.
The LED stays LIT (in both cases - with int and with your ...

Thanks, I will try what you have suggested. But which "other thread" are you quoting here? can you please give a link?

Hi
Toggling LED is already working fine with crude loop based delay.
But using timers it is not working. Tomorrow I plan to single step and debug using arduino.

Thanks

Hello,

I was trying delay routine using timer T1 of 6522.
In the code, basically, I have first configured LCM in 4bit mode and then after that setup the timer and toggle LED with the timer value.
Clock is 1MHz and timer value I have set is for 50ms (~50000)
I am checking for a count of 10 which ...

And that needs to be added (not multiplied which I did before) to the grand total giving 324870 cycles or about 1/3 of a second at 1Mhz.
-Gordon

I should say you have got a lot of patience. One that I always try to acquire from your generation. And I suppose your username seems to be an anagram ...