AVR Freaks

Correct, I did not write to MCLKCTRLB. as per my understanding of the following...

My understanding is that if you want the prescaler, then you write to PEN and PDIV.

For no prescaler, don't write either.

I didn't read anything about it being enabled on startup, but I will try writing zero and see what happens.

Thanks,

Brad

Thanks, I missed that one.

I also found that this would not work...

// ENABLE EXTERNAL CLOCK ON PORTA.3
ldi r16,216
ldi r17,3
ldi r18,0
out CPU_CCP,r16
sts CLKCTRL_MCLKCTRLA,r17
sts CLKCTRL_MCLKCTRLB,r18

Yet this does...

// ENABLE EXTERNAL CLOCK ON PORTA.3
ldi r16,216
ldi r17,3
ldi r18,0
out CPU_CCP,r16
sts CLKCTRL_MCLKCTRLA,r17
out CPU_CCP,r16
sts CLKCTRL_MCLKCTRLB,r18

Seems that "4 instruction cycles" actually means "4 clock cycles).

Assuming that the sts write actually happens on cycle #2, then it would be cycle #5 where it occurs... one too slow.

The speed just went up on my pin toggle, and I will measure it when I am back in my lab.

Thanks for the help, it's so much fun decoding a new chip like this.

Brad

Quark-85 now has an extra pin for sound without requiring any HV programming.

Using a common 4.3v Zener (BZX79-C4V3) like this...

This now leaves one free IO for PWM sound output, offering a lot more versatility for sound effects.

I will update the code soon, but here is how this works...

PINS B.0,1,2 are normally floating and pulled up externally.

When it comes time for Sync, B0,1 are set low, and enabled.

When Sync if over, PINS B.0,1,2 are set back to floating.

When it comes time for Color, B.0,1,3 are set to high, but not enabled.

To set Color Bits, DDRB is sent pixel data to toggle individual IO lines.

This setting of DDRB does not disturb the SYnc or Sound PIN.

When the Zener sees the positive voltage, it passes .68V to the Analog Color lines.

The 1K pullup on Sync does not make it past the diode.

Sound PIN B.4 is driven by PWM, mixed as 4 independent channels.

PIN B.5 is used for programming, and B.3 is the clock input.

I am going to leave this one as Quark-85 Demo Kube, and just create multimedia demos on it.

The Tiny 1614 based version Quark-1614 will evolve into a Game System.

Brad

Not yet.

I am going to convert the Quark Engine completely, using 36MHz @ 5V, and then see what happens with lower voltage.

As with the Atmega328, 38MHz is the bleeding edge, sometimes working at even 40 MHz, which is why I chose 36 MHz.

So far, the XMega holds the overclock record, all variants reaching 68MHz / 212% overclocking speed.

Next in line is the Tiny-85 and ATmega88, reaching 40 MHz / 200%.

Tiny-1614 seems good at 36 MHz / 180% along with ATmega328.

The only silicon on my bench that beats XMega for raw IO / SRAM speed is FPGA. Not ARM, not PIC32, not STM.

I wonder if that SAM thing would be any good? I might have to try that next.

Brad