MIni dock vs roiginal dock?
Eric Min last edited by
Which should I get? I'm currnetly thinking of the mini dock, since I'm not gonna use the GPIo and the mini dock is smaller.
Since you mentioned wanting to flash an OS here:
Go with the Expansion Dock + the Ethernet Expansion. This way, if you flash a buggy OS build, you will be able to recover much more easily.
@Eric-Min It really depends upon your intended usage.
The mini-dock is small and compact but does not expose any external connectivity other than the micro-USB for power and the standard USB for USB device(s) (e.g. memory stick).
The standard expansion dock is larger and does expose some (but not all - see below) of the Omega's pins. In particular, it exposes Serial pins, I2C pins, Ethernet as well as the GPIO pins while still providing the the micro-USB for power and the standard USB for USB device(s) (e.g. memory stick).
You may also want to consider the power dock if you wish to run your Omega standalone without an external power source.
From my perspective, there still exists a gap in the available dock facilities for the Omega.
- The mini-dock does not make any of the standard Omega pins externally accessible without soldering directly to the Omega or mini-dock headers.
- While the standard expansion dock does expose a significant fraction of the Omega pins, not all of them are exposed
- this is particularly so for the Omega2 which as well as pins for I2C, it shows groups of pins for SPI, and I2S well as 2 serial connections and ethernet connection
This lack of exposure is exacerbated by the fact that the Omega and mini-dock header spacing is 2mm which makes it harder to mechanically connect to more standard (more readily available) 0.1in headers and breadboards.
The standard expansion dock is primarily designed to provide access to existing expansion boards that don't need the full access of all of the Omega pins
What I would like to see is a version of the mini-dock that exposed
ALLthe Omega/Omega2 pins in standard 0.1 in headers. This would give some greater connectivity and while being larger than the existing mini-dock could still be significantly smaller than the standard expansion dock.
@Kit-Bishop i think the expansion dock breaks every out except the normal reset pin. Maybe look at my custom dock im Working on? 5x5cm. Nearly all pins broken out. Usb to Serial on baord, lipo or passive poe
@Matthias-Nowak Not 100% sure I agree with you in relation to all Omega pins being exposed on the standard expansion dock.
The issue is muddied by the fact that the available documentation on the pin out for the Omega and the Omega 2 differ from each other particularly in relation to the pin numbering.
Not withstanding that, the Omega and the Omega2 have 32 pins while the Expansion dock header has 30 pins.
Looking at the Omega only (what documentation is available for the Omega2 says the pin out is subject to change) it would appear that the Omega has GND on two pins and that all the rest are unique. Thus giving 31 distinct pins.
The expansion dock header duplicates the following pins:
- GND on 3 separate pins
- 5V on two separate pins (Noting also that 5V is NOT a pin on the Omega itself)
- 3.3V on two separate pins
Thus totalling only 25 distinct pins that correspond to one of the 31 distinct pins on the Omega - i.e. there are 6 Omega pins that are NOT broken out on the expansion header
@Kit-Bishop hmmm...i would rather wait because there will be some changes made in the omega2 pinout mainly because the new and old one differ too much to be compatible. Guess then we should look again at it. Im currently not home so i cant really look at the schematic again. I will report back later today in regards to the pinout of atleast the original omega.
But yeah: before doing more things around the pinout in the campaign we should wait for the next Update
@Kit-Bishop ok got to correct me on something: the reset button uses the FW RST Pin, and that one isnt broken out, but the normal RST Pin is.
So a list of pins not broken out:
- FW RST
- IO 15
- IO 16
- IO 17
so in theory, you loose 3 IOs. They could have broken them out if they had removed like one GND Pinout and one 5V/3.3V.
@Matthias-Nowak That's more in line with what I thought.
As far as I can figure out the correspondence between the
Omegapins and the
Expansion Dockpins is given by:
Omega Pin Expansion Dock Pin ============= ================== GND - 2 times GND - 3 times VOUT/2.8V 2.5V ??? 26 26 23 23 17 no pin 16 no pin 15 no pin 14 14 13 13 12 12 8 8 7 7 6 6 1 1 0 0 RST RST VIN/3.3V 3.3V - 2 times USB/D+ USB+ USB/D- USB- Serial/TX no pin Serial/RX no pin FW RST/11 no pin VOUT/2.0V 2V Ethernet/TX- TX- Ethernet/TX+ TX+ Ethernet/RX- RX- Ethernet/RX+ RX+ 18 18 19 19 I2C SCL/20 20 I2C SDA/21 21 no pin 5V - 2 times
So, as you indicate, there is no
Expansion Dockpin for the following
- FW RST
Though I am still unclear as to any access on the
Expansion Dockto the
The situation is further significantly complicated by the fact that from what has been available to date, the
Omega2has some significant differences in it's pin out compared to the
Omegato the extent that one wonders about the compatibility between the
Omegaand the current and any future
Expansion Dockand between the
Omega2and the current and any future
For reference, the following is what differences I have been able to deduce between the
Omega Pin Omega2 Pin Differences ============= ========== =========== GND - 2 times GND - 2 times None VOUT/2.8V 11 Usage 26 I2S CLK/3 Functional and Pin No 23 I2S WS/2 Functional and Pin No 17 17 None 16 16 None 15 15 None 14 Serial RX1/46 Functional and Pin No 13 Serial TX1/45 Functional and Pin No 12 SPI MISO/9 Functional and Pin No 8 SPI MOSI/8 Functional 7 SPI CLK/7 Functional 6 SPI CS1/6 Functional 1 I2S SDO/1 Functional 0 I2S SDI/0 Functional RST RST None VIN/3.3V VIN/3.3V None USB/D+ USB/D+ None USB/D- USB/D- None Serial/TX Serial RX0/13 Functional and Pin No? Serial/RX Serial TX0/12 Functional and Pin No? FW RST/11 FW RST/38 Pin No VOUT/2.0V VOUT/3.3V Functional Ethernet/TX- Ethernet/TX- None Ethernet/TX+ Ethernet/TX+ None Ethernet/RX- Ethernet/RX- None Ethernet/RX+ Ethernet/RX+ None 18 18 None 19 19 None I2C SCL/20 I2C SCL/4 Pin No I2C SDA/21 I2C SDA/5 Pin No
@Kit-Bishop well i think that function differences arent a major problem. But as said earlier, we will get an updated pinout with the next kickstarter update because ive messaged them already about the differences. So lets better wait until we get the new information.
@Matthias-Nowak While I agree that we really need final details on the Omega2 to know what is actually going on, I still have concerns about the different usage of pins on the
Omegaas against the
Omega2on what information is available to date - particularly in relation to the compatibility when each is plugged in to an existing
Different functionality and pin numbers in some case will require specific versions of code for each of
Omega2that use the pins that are different.
This covers the following set of pins:
- On Omega: 26, 23, 14, 13, 12, 20, 21, Serial/TX, Serial/RX
- And correspondingly on Omega2: 3, 2, 46, 45, 9, 4, 5, SerialRX0/13, SerialTX0/12
In addition, on the currently available information, I have concerns over the differences on the following sets of pins:
- Omega - VOUT/V2.8 ; Omega2 - Pin 11 : Nature of pins completely different
- Omega - Serial/TX and Serial/RX ; Omega2 - Serial RX0 and Serial TX0 : Opposite sense of TX and RX
- Omega - VOUT/2.0V ; Omega2 - VOUT/3.3V : different electrical characteristic potentially affecting connected external equipment
@Kit-Bishop (note: reffering to the omega1 schematics on github)yeah i was already worried about the 2.5v thing. Because that is used for the reset button, thus they have to change this if they want to keep the compability. Pin numbers could possibly be changed in firmware. For the last part: they have to use a different Voltage there. Its purpose is only to be there for ethernet power, so i dont think that people used that one for anything else before because it probably cant drive a big current. Plus they have to change that atleast for Ethernet to get working so i would pass that change
@Matthias-Nowak We seem to generally concur that there are some issues etc. that could be fruitfully addressed.
One final comment on all this in relation to pins 15, 16 and 17:
While these pins on the
Omega2are not exposed on the
Expansion Dock, they are used on the
Expansion Dockfor control of the expansion LED:
- Pin 15 - LED blue
- Pin 16 - LED green
- Pin 17 - LED red
However, note also that with the
Power Dockthere is no LED and so these pins are neither used nor exposed. It seems a shame to have 3 pins not exposed just to control an onboard LED that isn't always available