So, curious, the I/O pins on the P1 are logic gated together between cogs to determine the final output. Is there any real speed difference between the pins going through more or less gates? If so, which pins would be optimal to use between props?
There has been said to be some difference, but I personally haven't run into any issues, even with 20 MHz SPI. Some couple nanoseconds (a single CPU cycle @ 80Mhz is 12.5 ns!)
I think(!) that pins 0-15 are closest to cog 0 and pins 16-32 are closest to cog 7. Maybe the other way round. I'm sure there's a thread on here about it, but I can't find it right now.
Smaller opcodes for small constants versus referencing bigger values via "fake constants" in memory may be a thing there too. Code addressing lower pin numbers may be slightly faster.
Perhaps this has more impact than the distance from cog to pin...
Well, I have made symbols for the XBee and ESP32 Feather. I have, however been unable to resolve the incapacity to program the Feather. I posted to the Adafruit Forums(twice since June 7th), to no avail. if anyone here can help solve this, I would greatly appreciate it.
On the plus side, I have wired up the USB Prop! I will add the schematic once I fix my KiCAD Libraries. Screwed them up bad.
EDIT: Fixed the libraries! Here is the PDF:
Two things: One, I have renamed the device. The VIPMC, Virtually Infinite Propeller Modular Computer. This is dues to the nature of the stack, in that you can add cards to it to the limit of either the props memory and your power supply.
Two: I have been trying to get a QFP package sourced for EEPROMs. I’m just gonna use DIP sockets. That way I can program the EEPROMs on another board and mass produce programmed EEPROMs. This should also make firmware updates easier.
Feather programmability, SOLVED! (By purchasing a cable from Parallax.)
I have sorta familiarized myself with the Arduino IDE and I have nailed server and webpage hosting with it.
I am testing a Serial Initialization system using my PropBOE, Propeller Project Board, and PropMini. Pics later.
I prefer using male pin headers on main boards so that cables and modules are always female. Keep these connections along the edge of the PCB and if there are other pin headers then keep them in the same 0.1" grid. Avoid rats nest connectors that go all over the pcb.
Standard pitch pin headers are ubiquitous but I have boxes of them that I bought in bulk from 4ucon.
None of this should stop you from designing the PCB since you only have to allow for a connector. Once a PCB is being made you can decide whether to populate it or not with whatever fits. I prefer to use through-hole because they are easier to get and cheaper and also far less likely to rip off a pcb. Anyway, you can use a combo smd+th footprint so that you once again have the choice at assembly time.
I suppose I could redesign the CPU stack design so that it uses four 3-pin headers, rather than six 2-pin headers.
I need to be able to plug the CPU cards in one after the other, with each one facing the opposite way. I need 5 pins minimum with male pins facing downward, and female sockets facing upward. Here is my current plug, with 12 pins. 6 going up, 6 going down.
DIP EEPROM? There's the Microchip 24FC1026P, but that's 128K. I think there's also a 64K version (24FC512P I think?) but I recall it not being much cheaper.
So, I was talking with Support via email. The VGA connector that I have in my bin is no longer being sold. Support said that Newark was the supplier, but was unable to recall the part number. Anyone here know it?
I find VGA connectors not only bulky but you need mechanical support for them as well once a cable is plugged in which is all good and fine for a desktop PC, but not bare PCBs.
What I do instead is have a simple pin header, either a 8x2 way for common VGA+IDC plugs found on ebay or just the minimum 6 pins required. That way I can have my own cable plug into the pcb easily and directly into the monitor without all the bulk considering the Prop board is only a tiny PCB. This also allows you to use the standard VGA+IDC mounted to the chassis but connect via the 16-way IDC to the pcb, just like they do for video adapter cards on the PC. There are many variations of this but the point is to literally "think out of the box".
So, I was talking with Support via email. The VGA connector that I have in my bin is no longer being sold. Support said that Newark was the supplier, but was unable to recall the part number. Anyone here know it?
VGA connectors have a choice of size of price, plenty of large ones out there...
I have never seen this to be an issue with the plug on PropBOE, which is the same plug I have.
(Reply to Peter, didn't see jmg's post when I posted.)
Once a VGA cable is plugged in it ends up mechanically "over-powering" the tiny pcb and besides the VGA PCB connectors are bulky and footprints vary. What I have mentioned is my personal preference and from experience over decades of incorporating VGA onto pcbs themselves. Whether or not the chassis has a VGA connector itself is not a matter for the PCB to worry about. One Prop product I have has a male VGA connector on the pcb and is designed to mount inside an extended headshell so that it plugs directly into the monitor and it also has a USB socket for a PS/2 keypad. All I need to connect this to my system is a 4-wire connection for multi-drop RS485 and DC, so there is no need for a cable in this case (pun).
BTW, I'm talking about commercial products, not educational ones. Consider this information as food for thought.
BTW, I'm trying to get a head start on building the website for this feller. I'm trying to make a slideshow like the one at www.parallax.com. I want to be able to navigate between sheets using the buttons etc, and I also want it to advance automatically every 5 seconds. JavaScript is like my 30th language(not really) and thus not very well understood.
Sorry if this is the wrong place to ask, but I figured that it was related via the product.
Looking for a 3.7v regulator, 1A. This is an alternate method to powering the feather onboard. I choose this because I would like to avoid using a cut off usb plug sprouting from the board.
Also, the feather has a charge circuit which will try to supply voltage to the regulator backwards when plugged into USB. My idea is to mimic a battery, but with stable supply.
Comments
I think(!) that pins 0-15 are closest to cog 0 and pins 16-32 are closest to cog 7. Maybe the other way round. I'm sure there's a thread on here about it, but I can't find it right now.
Perhaps this has more impact than the distance from cog to pin...
That could make a difference in Spin only. PASM timing is the same regardless of whether the source is immediate.
However, pins 0-7 have the advantage of not needing to be shifted down to be WRBYTE'd...
On the plus side, I have wired up the USB Prop! I will add the schematic once I fix my KiCAD Libraries. Screwed them up bad.
EDIT: Fixed the libraries! Here is the PDF:
Two: I have been trying to get a QFP package sourced for EEPROMs. I’m just gonna use DIP sockets. That way I can program the EEPROMs on another board and mass produce programmed EEPROMs. This should also make firmware updates easier.
I have sorta familiarized myself with the Arduino IDE and I have nailed server and webpage hosting with it.
I am testing a Serial Initialization system using my PropBOE, Propeller Project Board, and PropMini. Pics later.
https://www.mouser.com/ProductDetail/NKK-Switches/GP0115ACCG30-R?qs=sGAEpiMZZMvxtGF7dlGNpjm6OJutkRKEA3AKEj%252B7mMI%3D
https://www.parallax.com/product/400-00002
Using the simpler button on the PCB and a jumper in parallel to easily add an off PCB reset button wherever you want is more flexible.
Surface mount or Through-Hole?
Standard pitch pin headers are ubiquitous but I have boxes of them that I bought in bulk from 4ucon.
None of this should stop you from designing the PCB since you only have to allow for a connector. Once a PCB is being made you can decide whether to populate it or not with whatever fits. I prefer to use through-hole because they are easier to get and cheaper and also far less likely to rip off a pcb. Anyway, you can use a combo smd+th footprint so that you once again have the choice at assembly time.
I need to be able to plug the CPU cards in one after the other, with each one facing the opposite way. I need 5 pins minimum with male pins facing downward, and female sockets facing upward. Here is my current plug, with 12 pins. 6 going up, 6 going down.
4uconnector.com/online/object/4udrawing/15201.pdf
Will this device work as a Propeller boot memory?
What I do instead is have a simple pin header, either a 8x2 way for common VGA+IDC plugs found on ebay or just the minimum 6 pins required. That way I can have my own cable plug into the pcb easily and directly into the monitor without all the bulk considering the Prop board is only a tiny PCB. This also allows you to use the standard VGA+IDC mounted to the chassis but connect via the 16-way IDC to the pcb, just like they do for video adapter cards on the PC. There are many variations of this but the point is to literally "think out of the box".
VGA connectors have a choice of size of price, plenty of large ones out there...
A popular compact VGA is something like
https://www.digikey.com/product-detail/en/edac-inc/634-015-274-992/151-1125-ND/2059408
or this, for lower-height
https://www.digikey.com/product-detail/en/norcomp-inc/200-015-213L537/NOR1731-ND/6834321
(Reply to Peter, didn't see jmg's post when I posted.)
Once a VGA cable is plugged in it ends up mechanically "over-powering" the tiny pcb and besides the VGA PCB connectors are bulky and footprints vary. What I have mentioned is my personal preference and from experience over decades of incorporating VGA onto pcbs themselves. Whether or not the chassis has a VGA connector itself is not a matter for the PCB to worry about. One Prop product I have has a male VGA connector on the pcb and is designed to mount inside an extended headshell so that it plugs directly into the monitor and it also has a USB socket for a PS/2 keypad. All I need to connect this to my system is a 4-wire connection for multi-drop RS485 and DC, so there is no need for a cable in this case (pun).
BTW, I'm talking about commercial products, not educational ones. Consider this information as food for thought.
If I must find a new VGA port, a vertical one may be ok. Looking at jmg's links.
Sorry if this is the wrong place to ask, but I figured that it was related via the product.
Also, the feather has a charge circuit which will try to supply voltage to the regulator backwards when plugged into USB. My idea is to mimic a battery, but with stable supply.