Component Advice Please?

[t0nyt]

Inspired by jobdone & others I've decided to break out of my comfort zone and have a go at building a couple of the Minerva MK II (I'd been playing with I2C on my BBC, but that's now in storage) so have ordered the PCB's to see how I get on

Putting to one-side, for the moment at least, my poor soldering skills & sourcing a different programmer so I can program the GALs, my lack of electronics knowledge means I'm struggling with some parts of the BOM

I was wondering if anyone could clarify a few things for me please?

C2, C3 are listed as "Value C" and I haven't a clue what that means

C1 radial is listed as "Value 30P" but is 30P the same as 30PF please?

U4 is a GAL16V8 & I have 2 unused ST brand marked GAL16V8S-25EB1 99036 in my spares box, are these suitable for U4 please?

And does anyone know if the TL866II (or III) will be able to program the GALs please?

Sorry for all the questions but this is all pretty much new to me but am excited to see if I can achieve it

Many thanks

[stephen_usher]

No idea about the values as those are not standard ways of defining them.

The TL866 should work to program those GALs though I usually use Atmel GALs these days.

[Popopo]

Inspired by jobdone & others I've decided to break out of my comfort zone and have a go at building a couple of the Minerva MK II (I'd been playing with I2C on my BBC, but that's now in storage) so have ordered the PCB's to see how I get on

Putting to one-side, for the moment at least, my poor soldering skills & sourcing a different programmer so I can program the GALs, my lack of electronics knowledge means I'm struggling with some parts of the BOM

I was wondering if anyone could clarify a few things for me please?

C2, C3 are listed as "Value C" and I haven't a clue what that means

C1 radial is listed as "Value 30P" but is 30P the same as 30PF please?

U4 is a GAL16V8 & I have 2 unused ST brand marked GAL16V8S-25EB1 99036 in my spares box, are these suitable for U4 please?

And does anyone know if the TL866II (or III) will be able to program the GALs please?

Sorry for all the questions but this is all pretty much new to me but am excited to see if I can achieve it

Many thanks

Hi and congrats for daring to go ahead!

C: Capacitors, there are two general types for this kind of projects: polarized (tantalum or Electrolytic) or not Polarized (The most common is MLCC (ceramic multilayer).
30p means 30 picoFarads.
About the GAL... you need to read specs and check what the BOM of the project requires. Some GALs 16V8 are different in the sense of extra I/O gates comparing with others same "type" that has some gates only for Input or Output. It is important (IMO) to consider the speed of the GAL and also the Power consumption. For QL, the Lattice 16V8D QP or LP are good enough, for this particular project I cannot assure it but I would bet for it.

TL866II works fine to program them, I use it very often.

About polarized capacitors... be aware about Voltage working requirements. To choose the correct one will assure a long working life. But be aware that more V Working usually means the increase of volume (size) and you could face problems to place them into a case. I am talking in general not for this particular project that I have no idea where it goes.

Any doubt, any... just ask, Also for soldering tips!

Edit: About C2,C3... I didn't see the schema but I bet they are decoupling capacitors. The most common values are 100nF, 10nF depending on. Fast way to get the right is to ask to the author of the project. Otherwise open the DCDC regulator (If there is one) and read the datasheet with special observation of the values that it recommends for those capactitors, then comparing the schema from the datasheet with the schema of the project and figure out if they match.

[t0nyt]

Thanks both

I’m clear now on getting a TL866ii & that I may need different GALs (will worry about that once I’ve tried the ones I have)

Still can’t get my head around the capacitors though

Many thanks

[Derek_Stewart]

Hi,

Look on the TL866II website, there is a list of support devices.

I have the TL866 v1 which seem to do nothing old.

[Arleybls]

C2 and C3 are probably for the crystal, they will vary depending of the capacitance of the crystal, but since they do not show up on the original schematics I suppose that is why you don't need to populate them. C1 is 30pf MAX, it is supposed to be trimmer exactly to adjust according as well to the capacitance of the crystal(?)

[t0nyt]

Hi,

Look on the TL866II website, there is a list of support devices.

I have the TL866 v1 which seem to do nothing old.

I haven't a clue what counts as old or new tbh or what type will work in the Minerva Mk2 board, so it's going to have to be hit or miss I guess

EDIT: techy has advised me which GAL's to get to use with the board & TL866. Many thanks

[techy]

sent you a pm

[t0nyt]

C2 and C3 are probably for the crystal, they will vary depending of the capacitance of the crystal, but since they do not show up on the original schematics I suppose that is why you don't need to populate them. C1 is 30pf MAX, it is supposed to be trimmer exactly to adjust according as well to the capacitance of the crystal(?)

Why do you say they don't need to be populated please?

EDIT: techy has explained to me that C2,C3 aren't used now. I was just working to the BOM

Many thanks

[t0nyt]

Everything is now on order, will report back when I’ve tried soldering it all together!