I looked at the arduino page for the LCD API, and it says it supports both parallel and serial LCD's, so seems like the code should work with either.
(Priyesh pointed this out to me)
LCD API page
With a parallel LCD, dimming and contrast have to be done with pots.
Randy
I think something is wrong with your spreadsheet. I can't seem to open it up.
I just opened it up, but I had to figure out how to show file extensions in Windows 7 first, then rename the extension to .xls, and it worked. If adobe is trying to open it, the extension is wrong.
I have a question on the crystal.
I think the capacitance you put on the crystal depends on the crystal used.
Do has chosen a crystal with 18pf, so I think the two crystal caps should change to 18pf.
Right now, the file shows 30pf caps.
Should it change?
Randy
Are you referring to C28, C29? If yes, they're 33pF but the closest match I can find for a 12Mhz crystal is 32pF...
Not to sure about this one. If you're sure then I'll just change the part for the crystal.
I see. That is something new. That is a layer on top of the "native" or LCD-specific libraries. I use the "native" libraries. Parallel LCDs are more popular and cheaper.
I would recommend taking a look at this: https://bitbucket.org/fmalpartida/new-liquidcrystal/wiki/Home
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For the IC packages, the 8741 only comes in one package, and the 2707 only comes in one square package.
For the others, since you know the header pins are on 1/10" centers, you can come up with a scale, and measure the parts.
Doing this, the IC's are SO14, the little gates are DBV.
The watchdog only comes in one package, and the voltage regs only come in one 5 pin package.
Randy
For the others, since you know the header pins are on 1/10" centers, you can come up with a scale, and measure the parts.
Doing this, the IC's are SO14, the little gates are DBV.
The watchdog only comes in one package, and the voltage regs only come in one 5 pin package.
Randy
Latest BOM for Digikey
I've added everything in detail in the BOM but cannot find the Sanyo Oscon anywhere... You could get the Organic Polymer Caps which are essentially the same...
The Wolfson DAC and receiver are at Mouser as well as the two 100pF and 220pF Wima FKP caps... Digi had no stock on equivalent product.
The BOM contains the Wolfson Receiver, Level Converter and MiniDAC parts.
Ciao!
Do
I've added everything in detail in the BOM but cannot find the Sanyo Oscon anywhere... You could get the Organic Polymer Caps which are essentially the same...
The Wolfson DAC and receiver are at Mouser as well as the two 100pF and 220pF Wima FKP caps... Digi had no stock on equivalent product.
The BOM contains the Wolfson Receiver, Level Converter and MiniDAC parts.
Ciao!
Do
I figured out my question about load caps and crystals.
Crystek app note for load caps
Fox has a similar app note, but it gives a fixed approximation for the Cin and Cout capacitance, which is this case is based on the PCM2707. The PCM2707 datasheet does not specifiy, so I used 5 pf.
Based on 5 pf for the PCM2707, and 3 pf for trace capacitance, if you use 30 pf caps on the crystal, load is 20.5.
To get a load capacitance of 18, you need to use 25 pf caps. Problem is that it looks like 25 pf caps are special order from Mouser, not sure about digikey.
So, 30pf may be as close as you can find that is in stock at a distributor.
Randy
Crystek app note for load caps
Fox has a similar app note, but it gives a fixed approximation for the Cin and Cout capacitance, which is this case is based on the PCM2707. The PCM2707 datasheet does not specifiy, so I used 5 pf.
Based on 5 pf for the PCM2707, and 3 pf for trace capacitance, if you use 30 pf caps on the crystal, load is 20.5.
To get a load capacitance of 18, you need to use 25 pf caps. Problem is that it looks like 25 pf caps are special order from Mouser, not sure about digikey.
So, 30pf may be as close as you can find that is in stock at a distributor.
Randy
Yet another update!
Based on calcs done by randytsuch, I've got the closest match available for 0805 ceram caps.
Both caps on Wolfson receiver and MiniDac have changed to accomodate this.
On MiniDAC, removed 33pF and changed to 27pF
On receiver, removed 22pF and changed to 27pF
Both Crystals are 12Mhz 10PPM 18pF
@randytsuch, do you have a Mouser BOM to share?
Ciao!
Do
Based on calcs done by randytsuch, I've got the closest match available for 0805 ceram caps.
Both caps on Wolfson receiver and MiniDac have changed to accomodate this.
On MiniDAC, removed 33pF and changed to 27pF
On receiver, removed 22pF and changed to 27pF
Both Crystals are 12Mhz 10PPM 18pF
@randytsuch, do you have a Mouser BOM to share?
Ciao!
Do
I am building a "custom" version, so my BOM wouldn't really help.
I decided to delete the headphone amp (I have better ones already), and to use a different output stage, so I deleted that too.
Randy
The output stage obviously is the weak link here. +5V opamp delivering (I think?) a 2vrms signal is going to be relatively high THD I am afraid. Shouldn't we use a dual supply opamp to combine the differential signals, get the cmrr and possibly lose the output cap? Thinking somehow using the headamp spots for a better analog stage.
The datasheet shows a nice output stage but doesn't name the opamps, also there is the balanced to unbalanced line level transformer approach to consider.
I guess I didn't buy this as a mini-dac, more for the software control and I think potential to meet the reference performance with a few mods.
Guys, I'm all for a better output stage!
Anyone willing to take the lead on this?
I have two of those transformers at home http://www.lundahl.se/pdfs/datash/1545a.pdf
I'm guessing I could surely try them out?
It would be interesting to see what can be done. I couldn't care less about the headphone amplifier in this circuit.
Ciao!
Do
Anyone willing to take the lead on this?
I have two of those transformers at home http://www.lundahl.se/pdfs/datash/1545a.pdf
I'm guessing I could surely try them out?
It would be interesting to see what can be done. I couldn't care less about the headphone amplifier in this circuit.
Ciao!
Do
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I'd agree with you by bypassing the headphone amp.
Look here for transformer output from the dac....
Passive output
It would look pretty similar to the Nekko Audio DAC ( http://www.nekoaudio.com/ ) with the transformers in there.
Look here for transformer output from the dac....
Passive output
It would look pretty similar to the Nekko Audio DAC ( http://www.nekoaudio.com/ ) with the transformers in there.
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Looks pretty simple to me. However, that Lundahl LL1674 is on the expensive side. I paid 85$ per 1545A and never got to use them... It is a shame!
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