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Re: Level Shifting
Yes. Use ULN280x parts... I use them for everything where I need to drive
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stuff... Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ Owner - Operator Big Signal Ranch – K9ZC Staunton, Illinois Owner – Operator Villa Grand Piton – J68HZ Soufriere, St. Lucia W.I. Rent it: www.VillaGrandPiton.com Moderator: North American QRO Group at Groups.IO. Moderator: Amateur Radio Builders Group at Groups.IO. email:? bill@... -----Original Message-----
From: jerry <jerry@...> Sent: Friday, February 7, 2025 12:19 PM To: [email protected] Cc: K9HZ <bill@...> Subject: Level Shifting Hello, This has very little to do with the T41... I have this homebrew linear. It interfaces with my T41 quite nicely. Just like the T41, it has a Teensy 4.1 inside. Bands are chosen using Yaesu "BCD" band codes. Four wires, each one can be "high" or "low" gives you a four bit code and 16 possible bands. The standard is that "high" is near 5V, and "low" is near 0V. Just like in the old TTL days. The Teensies, however are 3.3V devices. Any inconveniences are compensated by the fact that they are WAY faster than any 5V Arduino. When I built the linear, I converted the 5V ( from an FTDX10 ) to 3.3V with a resistive voltage divider. When I built the T41, I converted the 3.3V from the Teensy to 5V using an open-collector transistor switch in each line. The problem with this is that the noise immunity is not good. So when the linear starts transmitting, RF gets into the band-chooser lines. The linear changes to a different band, and the protection circuit then says "Oh you have the wrong LPF", and shuts off the power. I *love* that protection circuit. I am still on my first MRF1K50. No amount of bypassing fixed it. I have bypassing and RF chokes at the T41, I have bypassing at the linear. I shielded the cable between them. I mostly fixed it by saying "We never change bands during transmit, so ignore those lines at that time". How to know that we're in transmit? Software on the Teensy monitors the drain current of the MRF1K50. If it's greater than zero, we're transmitting. But for some reason, it still does it on 10M if I run more than 800W or so. Doubtless RF starts coming out before the Teensy notices the drain current.... I guess. ANYWAY - the recent discussion about level shifters intrigued me. Is there an IC solution that's better than open-collector drivers and resistive voltage dividers? One that has decent noise immunity? It does not have to be fast; these lines are essentially DC. - Jerry, KF6VB |
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Re: Conductive Paint
开云体育All interesting stuff… I see Prusa are marketing a PETG Magnetite ?which may have decent electromagnetic shielding. ?Not cheap tho they also have a V0 filament, ?Prusament PETG V0 is the one-in-the-world UL-certified self-extinguishing PETG filament. Similar to the regular Prusament PETG, it is a tough material with good thermal resistance. Its use is universal but it is especially suitable for housings and insulating parts in electronics, due to its self-extinguishing properties ? Other products are available by other manufacturers, probably… ? Expensive, but once I’ve finished everything I’ll but a reel and see how I get on… ? If anyone is buying a 3D printer and consider a Prusa, use this code @Chris_80193, there is a small referral benefit…. ?, their new Core1 looks magic… I’ve upgraded my mk3 to mk3S, to mk4 and added a multicolour MMU2->MMU3 ? My neighbour after much deliberation (support was his clincher, not the cheapest) went for a resin printer, he’s going to try some lost wax bronze casting ?for his 4” traction engines he’s building, a whole new world… ? For your amusement, form over substance maybe….no idea why I printed the numbers….. not as if I had to take off my socks ? ?
? ? ? ? ? ? From: [email protected] <[email protected]>
On Behalf Of K9HZ
Sent: 07 February 2025 14:37 To: [email protected] Subject: Re: [AmateurRadioBuilders] Conductive Paint ? This one I’ve used for building guitars… ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ ? Owner - Operator Big Signal Ranch – K9ZC Staunton, Illinois ? Owner – Operator Villa Grand Piton – J68HZ Soufriere, St. Lucia W.I. Rent it: ? Moderator: North American QRO Group at Groups.IO. Moderator: Amateur Radio Builders Group at Groups.IO. ? email:? bill@... ? ? From:
[email protected] <[email protected]>
On Behalf Of John ? Check this out, they are a trusted very well established comapany and the tech sheet makes interesting reading. Not sure about supply in the States, over here MG Chemical is very expensive. |
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Re: Conductive Paint
开云体育This one I’ve used for building guitars… ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ ? Owner - Operator Big Signal Ranch – K9ZC Staunton, Illinois ? Owner – Operator Villa Grand Piton – J68HZ Soufriere, St. Lucia W.I. Rent it: ? Moderator: North American QRO Group at Groups.IO. Moderator: Amateur Radio Builders Group at Groups.IO. ? email:? bill@... ? ? From: [email protected] <[email protected]> On Behalf Of John
Sent: Friday, February 7, 2025 4:18 AM To: [email protected] Subject: Re: [AmateurRadioBuilders] Conductive Paint ? Check this out, they are a trusted very well established comapany and the tech sheet makes interesting reading. Not sure about supply in the States, over here MG Chemical is very expensive. |
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Re: Display Adapter
开云体育Exactly. ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ ? Owner - Operator Big Signal Ranch – K9ZC Staunton, Illinois ? Owner – Operator Villa Grand Piton – J68HZ Soufriere, St. Lucia W.I. Rent it: ? Moderator: North American QRO Group at Groups.IO. Moderator: Amateur Radio Builders Group at Groups.IO. ? email:? bill@... ? ? From: [email protected] <[email protected]> On Behalf Of Terrance Robertson, KN6ZDE via groups.io
Sent: Thursday, February 6, 2025 9:45 PM To: [email protected] Subject: Re: [AmateurRadioBuilders] Display Adapter ? Yeah, since it's a digital isolator, it needs an independent 3.3V source when the display is run at 5V.? At least for it to be plug and play. |
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Re: [SoftwareControlledHamRadio] [AmateurRadioBuilders] Display Adapter
No. data line voltages at 3.3 and VSS to the display requlator of 5V...
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Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ Owner - Operator Big Signal Ranch – K9ZC Staunton, Illinois Owner – Operator Villa Grand Piton – J68HZ Soufriere, St. Lucia W.I. Rent it: www.VillaGrandPiton.com Moderator: North American QRO Group at Groups.IO. Moderator: Amateur Radio Builders Group at Groups.IO. email:? bill@... -----Original Message-----
From: [email protected] <[email protected]> On Behalf Of jerry-KF6VB Sent: Thursday, February 6, 2025 9:25 PM To: [email protected] Cc: [email protected] Subject: Re: [SoftwareControlledHamRadio] [AmateurRadioBuilders] Display Adapter By "operating the display at 5V", you mean 5V logic? - Jerry, KF6VB On 2025-02-06 19:17, K9HZ wrote: This one will work for operating the display at 3.3V and 5V. It's |
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Display Adapter
开云体育This one will work for operating the display at 3.3V and 5V.? It’s about $0.60 more that the strictly 3.3V driver board. ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ ? Owner - Operator Big Signal Ranch – K9ZC Staunton, Illinois ? Owner – Operator Villa Grand Piton – J68HZ Soufriere, St. Lucia W.I. Rent it: ? Moderator: North American QRO Group at Groups.IO. Moderator: Amateur Radio Builders Group at Groups.IO. ? email:? bill@... ? ? |
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Re: [SoftwareControlledHamRadio] Display driver board reality
On 2025-02-06 11:50, K9HZ wrote:
What’s the model number of your 5” board?E510512 - That's what's in the radio at this time. I have a 7-incher waiting for me to fabricate a new front panel. I'm thinking aluminum, CNC machined with my router. - Jerry |
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Re: [SoftwareControlledHamRadio] Display driver board reality
开云体育What’s the model number of your 5” board?? I only use 7” boards… I have FOUR different model numbers and from what I can tell they all have native 3.3V operation… and also a 5V regulator for operation/ level converters for the data lines… IF you want to use them/ select the right jumpers on the board. ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ ? Owner - Operator Big Signal Ranch – K9ZC Staunton, Illinois ? Owner – Operator Villa Grand Piton – J68HZ Soufriere, St. Lucia W.I. Rent it: ? Moderator: North American QRO Group at Groups.IO. Moderator: Amateur Radio Builders Group at Groups.IO. ? email:? bill@... ? ? From: [email protected] <[email protected]> On Behalf Of jerry-KF6VB
Sent: Thursday, February 6, 2025 1:36 PM To: [email protected] Cc: [email protected] Subject: Re: [AmateurRadioBuilders] [SoftwareControlledHamRadio] Display driver board reality ? My understanding is the the 5" board is 3v3 - period. The 5V option
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Re: Display driver board reality
开云体育That’s kinda where I’m heading… ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ ? Owner - Operator Big Signal Ranch – K9ZC Staunton, Illinois ? Owner – Operator Villa Grand Piton – J68HZ Soufriere, St. Lucia W.I. Rent it: ? Moderator: North American QRO Group at Groups.IO. Moderator: Amateur Radio Builders Group at Groups.IO. ? email:? bill@... ? ? From: [email protected] <[email protected]> On Behalf Of jerry-KF6VB
Sent: Thursday, February 6, 2025 1:43 PM To: [email protected] Subject: Re: [AmateurRadioBuilders] Display driver board reality ? n 2025-02-06 11:29, K9HZ wrote:
I vote for keeping it simple. If you jumper the main board for |
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Display driver board reality
开云体育Oh brother, this is starting to get complicated. ? The RA8875 is a 3.3V chip… and the inputs, as far as I can tell… from my research so far… are only 3.3V tolerant.?? ? To make this more confusing, some of the display.com displays have level shifting hardware onboard that you can enable to use the display as a 3.3V display or as a 5V display (in line with the power selections on the MAIN board).? However, not all do (particularly the smaller displays). ?The boards I made work with 3.3V and 5V display boards… which is fine for 3.3V operation for all display boards…. The problem comes if you select 5V operation bon the MAIN board… but either don’t have a 5V control line selection on the display board for level change to 3.3V for the RA8875… or if you DO have the level change hardware on your display board but have not selected it.? In this case, you will destroy the RA8875 chip. ? I can do two things.? One is to put together a list of all the approved Display.com display part numbers (upper middle of the back of the display) and give guidance on what you need to do so that the display continues to function with this driver board.? The other thing I can do is make a second board that has a tiny 3.3V regulator on it to power the three control lines to just 3.3V in the case of running the display off 5V but no hardware is there for level shifting the data lines to 3.3V. ? Comments? ?????? ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ ? Owner - Operator Big Signal Ranch – K9ZC Staunton, Illinois ? Owner – Operator Villa Grand Piton – J68HZ Soufriere, St. Lucia W.I. Rent it: ? Moderator: North American QRO Group at Groups.IO. Moderator: Amateur Radio Builders Group at Groups.IO. ? email:? bill@... ? ? |
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Re: [SoftwareControlledHamRadio] Display driver kits shortly
开云体育Well fact is… I’ve already done that… sort of…. For my prototype, I installed a 2x4 socket in a 2x5 holes pattern on the PCB knowing full well that 2 of the 10 holes on the end of the 2x5 connector are N/C. ? However, good news!? I was able to find 10,000 of them surplus for a very low price.? They will be here next week. ? There is another issue I discovered.? The ISO7241 SPI driver chip has two forms… an “M” form and a “C” form.? Here is the difference: ? “The devices with the C suffix (C option) have TTL input thresholds and a noise-filter at the input that prevents transient pulses from being passed to the output of the device. The devices with the M suffix (M option) have CMOS VCC/2 input thresholds and do not have the input noise filter or the additional propagation delay.” ? For electrically operating it won’t make a difference.? What might make a difference is the noise filter in the “C” version and I have not explored that (eg only have used the “M” version.?? I suspect the “C” version may work better for people in high EMI situations.? So I’m gonna make a few of each… send them out to a few folks here with finished radios and see which works best for them.? Unfortunately, I don’t have a high EMI location… so for me testing them may not be a fair comparison. ? ? Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ ? Owner - Operator Big Signal Ranch – K9ZC Staunton, Illinois ? Owner – Operator Villa Grand Piton – J68HZ Soufriere, St. Lucia W.I. Rent it: ? Moderator: North American QRO Group at Groups.IO. Moderator: Amateur Radio Builders Group at Groups.IO. ? email:? bill@... ? ? From: [email protected] <[email protected]> On Behalf Of bruce williams via groups.io
Sent: Thursday, February 6, 2025 12:11 PM To: [email protected] Subject: Re: [SoftwareControlledHamRadio] Display driver kits shortly ? Or depending on layout can you use the 2x6 and just snip 2 pins.? Is there real estate on the board for that? |
K9HZ
