[Coco] Cassette Program Loading Help Needed

[RETRO Innovations]

On 3/18/2017 10:05 PM, Arthur Flexser wrote:
> Maybe the program wants CLOADM rather than CLOAD?
I doubt it, because the data was saved via CSAVE

At the very least, I'd expect the filename to show.

I think I see the issue, but not sure how to fix.

AVR running at 8MHz
PWM in 8 bit mode
31250 PWM cycles per second (8000000/256)
Using two patterns for 1200Hz and 2400Hz sine waves:

const uint8_t _2400Hz[] = 
{0x0,0x11,0x40,0x80,0xbf,0xee,0xff,0xee,0xbf,0x80,0x40,0x11};
const uint8_t _1200Hz[] = 
{0x0,0x4,0x11,0x25,0x40,0x5f,0x80,0xa0,0xbf,0xda,0xee,0xfb,0xff
,0xfb,0xee,0xda,0xbf,0xa0,0x80,0x5f,0x40,0x25,0x11,0x4};

Output is 0-5V swing, run through a low pass filter (68ohm to 1uF, with 
other end of cap to ground.)

However, the output is very choppy, and I think it is messing with the 
internal comparator

Anyone have ideas on how to clean the output up?  I can go to a 6 bit 
Resistor D to A, but it'll eat up way too many pins on the design.

Jim