Crystal module upgrade to 16MHz?

MIDIbox FM
1

Hello all,

I would like to know if one can use a crystal module of 16MHz instead of 14.318MHz (Its hard to track the 14.3 and I have one 16MHz).

The YMF262 datasheet refers the max. clock @ 16MHz. Is it possible to tweak the code somewhere?

Thanks all.

Cheers,

ricardo

2

Hi Ricardo,

the frequency mapping can be changed in mbfm_frq_table.inc and mbfm_frq_table_alt.inc - the values have been calculated with the utils/frqtab.pl script. The frequency factor (49715.0) is based on the formula fs=FM/288 of the datasheet, it needs to be adapted (for 16 MHz -> 55555.5)

Best Regards, Thorsten.

3

Happy new year to all!

Thanks Thorsten for your awesome work/joy @ midibox apps!

I will try it soon, hopefully. (some stuff still to build b4 :slight_smile:

Regards,

ricardo

4

Hey Ricardo, did you tried it? It is impossible to find something with 14.318MHz value locally but 16MHz is available.

Thorsten, was there a special reason you used 14.318MHz instead widely available 16MHz oscillator?

5

you can find 14,318 MHz crystals in some old AT motherboards, old PCI Video cards, old ISA audio cards.

it’s a common frequency in all old computer hardware!

6

Ill try to. But Iwouldn`t count on that. Thanks for the info.  :wink: