Supporting the Pi Zero

The latest version of the Raspberry Pi is the Zero – a much smaller (and cheaper) circuit board similar in function to the model A (i.e. with one USB port and no Ethernet socket) but designed to be small and cheap. The Raspberry Pi Zero (click to see picture of a Zero installed inside a small case) will shortly be available more widely after the initial batch at the end of November quickly sold out.

The most likely application for this board is as a control board soldered inside some sort of hardware project, possibly with a touchscreen, rather than as a desktop machine. A model B might be used to develop and test the software on the SD card. Using the Zero as a desktop machine requires a lot of added bits and pieces such as USB hub, Ethernet adapter and special cables to fit the miniature sockets, pushing up the price.

So can you simply clone the SD card from your model B running RISC OS and put it in the Zero? Unfortunately not – the Zero needs the latest firmware. Using the latest firmware causes the processor to default to slow speed (allowing the kernel to ask for the higher speed ‘as required’, which RISC OS on the Pi does not yet do) and so the configuration (called ‘CONFIG/TXT’) needs to be adjusted to force ‘turbo’ mode.

Can you add a popular make of USB to Ethernet adapter (more likely to be necessary on a machine with no Ethernet socket)? Only if you use a RISC OS ROM from 20-Dec-2015 (which has drivers for AX8872B-based adapters) – any later (e.g. a latest development rom from the ROOL download page) and complications arise from ZeroPain (don’t ask).

How do you update your existing RC14-based SD card running RISC OS 5.2x to work on the Zero as well? An update zip file is available here which can simply be downloaded on your existing Raspberry Pi running RISC OS and the contents copied over your existing !Boot directory. Note: this relies upon the image file ‘Loader’ being recognised as an image filing system so it is best to open it to make sure, before doing the copying. It will update your firmware and ROM. Provided you are running RISC OS 5.2x this should work without affecting any of your data or programmes that you might have added since creating your SD card. You may need to update your configuration settings within RISC OS (such as screen size) as a new ROM will start with default settings.

What is provided in the zip file? A picture speaks more than words:

What if you are starting afresh with just a Zero? You will need to wait until ROOL update the RC14 SD card image to cope with the Pi Zero – this requires testing and may take some time.

Some ideas for a project using the Raspberry Pi Zero, with a touchscreen in place of mouse and keyboard for input, may be found here.

I have just recieved a “Ugreen” usb to RJ45 adaptor (and 3 usb hub)
which is intended for use with my Christmas Pi.

As a QUICK TEST it has been connected to the Pi B,with the net cable
changed over. On entering the ‘configure.network’ setup the display showed both a USB 0 and a USB 1 and after entering the network details,with a different IP address, well. here I am £10·99 well spent.

Now to add back the internet files I rmoved from the Pizero micro card
that was used for testing and away we go. I have already proved Hard Disc access with an old disc from the Risc PC (after re formst) mounted in an external IDE/SATA enclosure, from Curry/PCWorld. £17·99)

Today I found that the Pi Zero will run happily when it gets power from the USB port on theside of the Celcus TV (Sainsburys) 5·08 /5·11 volts.

Maybe the Raspberry Pi page on here needs a few updates? Can anyone edit them?

I have wondered if anyone would/could host their own ‘unofficial’ SD card images. Might be fun to create one with the latest code so it is newbie-friendly for all Pis? Or is there a way to assist ROOL with RC15?

Sorry for repost, but I’ll only do this once in case anyone missed it the other day.
Part of E-mail I received from Pimoroni on 23rd Jan @11:11am.

“Pi Zero?

We’ll have a new stock of Pi Zero available on Tuesday 26th of January which will be made available to buy at 12:00 GMT! We expect them to go quickly so make sure you’re ready! It will remain one Pi Zero per order just as we have done in previous batches.

I managed to drop on one just after Christmas and just thought I’d try and give everyone the heads up again.

I have made a Image. Works with my Zero. I have send the first link (without ROM changes) to Chris. The “new” Image is with a new ROM (2016-01-03). Not sure why it not works with all Zero… https://www.riscosopen.org/forum/forums/4/topics/3847?page=1#posts-49215…
I use a Lindy USBtoEther adapter with MCS7830 chipset… works fine without changes! I have also a Asix AX88X72 adapter but I must “*Set EtherUSB$Product_VVVV_PPPP [:]” via obey in Predesk.

Edit: Any problems… https://www.riscosopen.org/forum/forums/4/topics/3847?page=1#posts-49304

Both myself and Raik have noticed an issue with screen resolutions on the Pi Zero, especially with the LapDock.

Once up and running on the desktop, changing to 1360×768 using Configure:Screen works fine, but once this resolution is set and the machine is rebooted, it produces a mangled picture on next boot:

We’ve both independently resolved the issue by including an Obey file in Boot.Tasks setting the resolution to 1360×768, having set the resolution using Configure:Screen and initially booting to 1280×720. This seems to work, but it is very confusing that it can clearly display 1360×768 but can’t boot directly to it. The very same MicroSD cards will boot directly to 1360×768 on an A+, B+ or Pi2 – making me suspect it’s possibly a hardware compatibility issue?

Is anyone else experiencing this? Any idea why?!

Out of curiosity I’ve just tried changing the screen resolution through Configure.
I have the monitor type as Generic as it seems to give a lot of options for resolutions and I have various screens I keep using.
The native resolution of the monitor I’m using at the moment is 1920×1080.
I have tried various resolutions and all seem fine except for the 1360×768 which displays the same issue you seem to have.
I’ve tried this on RPi A+, B+, 2 and Zero. All have the same result.
So I’ve had a look in !Boot.Resources.Configure.Monitors.Other.Generic . There is no sign of the 1360×768 option. My thinking was it might be corrupt. So I deleted all but the first mode definition and saved as Generic2. Now I change the monitor type to Generic2 and still get a selection of resolutions. The first one from the file and 6 others. The same 6 are also there when I select any other monitor. Where are these options coming from? And is there a problem with the 1360×768 option?
Setting the display manually probably bypasses this option and sets the resolution directly.
Nevermind! F12 wimpmode x1360 y768 c16m still displays as your picture!

I used all the latest files I could find at the start of 2016 and the rom image is 5.23(03-Jan-16)

I must admit that I have noticed [on the Zero] that, despite adding an 800×480 screen mode to Other.Generic and manually editing the PreDesk.Configure.Monitors file to say X800 Y480, it wasn’t retaining the screen configuration over a boot. Most irritating when your only input device is a touchscreen and you can longer click in the right place to sort it out. So I copied the Monitors Obey file into PreDesk itself so the system can’t mungle it and all was then well. This is probably not the most elegant solution but it works reliably!

I have always thought that the monitor configuration on the Pi, where the GPU interposes between the RISC OS kernel and the monitor, is bizarre and anachronistic. Only a single monitor ‘GPU’ is required, with every resolution and colour depth available, leaving the timings to the GPU (it ignores the timings from the MDF anyway). A custom configuration interface would be nice, where you can just set x and y resolution separately from a writeable field with up and down icons.

It is unfortunate that RISC OS cannot see the result of the GPU’s interrogation of the monitor – the resolution it will actually use between iteslf and the monitor – as this would allow a much more sensible choice to be presented to the user as useful defaults for RISC OS.

Even a little bit confused why it works differently to the other Pi models. With the same monitor. I tried a TV which also uses 1360×768. A, A +, B, B +, 2 are working with the same settings in Predesk (and config.txt), Zero not. But Zero works if I move the monitor settings to Tasks …
If I try *ReadEDID and *CreateModeFile, the results are different. In the Zero MDF the higher resolution modes are missing. The MDF is incomplete.

“Where are these options coming from?”

I’ve found the answer to my own question! Turns out the extra options were coming from the Anymode module I had running.
But I experienced the 1360×768 not working on any RPi hardware, and I’ve just tried it on RPCEmu and it doesn’t work on that either.
For text on anymode see here
Sorry it doesn’t help with your issue.

andym and Raik

Are you also editing the config.txt file to make the GPU output match the native resolution of the screen in the first place?
I do this for each monitor or TV I have, then adjust the RISC OS settings to the same.
I don’t have a 1360×768 resolution screen to try it on though.

From http://elinux.org/RPiconfig

These values are valid if hdmi_group=2 (DMT)

hdmi_mode=39 1360×768 60 Hz
hdmi_mode=40 1360×768 120 Hz Reduced blanking
hdmi_mode=81 1366×768 60 Hz
hdmi_mode=86 1366×768 Reduced blanking

It is a good idea to force the native resolution of your screen. Particularly if it is an unusual one.

Config.txt: This is what I mean as I wrote “same settings”… all the same, with or without this in config.txt. If I use from Predesk it fails only with the Zero, if I set in task or later, it works also with the zero…

This thread is about supporting the Pi Zero, which requires recent (Nov 2015) firmware for RISC OS. With such recent firmware, the default clock settings (1000MHz on Zero, 900MHz on model 2 and 700MHz otherwise) are ignored and a slow ‘idle’ speed of 600MHz imposed, the intention being to boost to the default speeds when requested by the kernel, something RISC OS does not yet do on the Pi (but does on Pandaboard, Titanium and ARMX6).

For the Zero therefore, the update zip (see above) alters CONFIG.TXT to force 1000MHz continuously by using the following parameters:

arm_freq=1000
gpu_freq=300
core_freq=400
sdram_freq=450
force_turbo=1

If you want to use the more recent firmware on your model 1 or model 2 Pi then a more modest overclocking is advisable more like:

Model 1:

arm_freq=850
gpu_freq=300
core_freq=450
sdram_freq=450
force_turbo=1

Model 2:

arm_freq=1000
gpu_freq=300
core_freq=450
sdram_freq=450
force_turbo=1

Brand new forum, RiscOS and PiZero user here. Chris, thank you for this early work to get RiscOS running on the PiZero but I’m having screen geometry issues… I’ve posted (with images) on the raspberrypi forum – https://www.raspberrypi.org/forums/viewtopic.php?f=55&t=136395&p=906835#p906835

I have just recieved a “Ugreen” usb to RJ45 adaptor (and 3 usb hub) which is intended for use with my Christmas Pi. As a QUICK TEST it has been connected to the Pi B,with the net cable changed over. On entering the ‘configure.network’ setup the display showed both

I can confirm that this works with the Pi Zero too, as expected.

Is your monitor HDMI? The GPU usually gets the display right unless you are using a convertor of some sort. There are commands to put into config.txt that change the overscan until it lines up with the edge.

Yes, my display in HDMI – although it does have an input splitter attached so that I can plug in a few other devices to the same display without having to unplug cables all the time.

After reading this thread more carefully, I was looking for a command line equivalent in RiscOS but haven’t found it – navigation being tricky at the moment… Where do I find / how do I create a monitor obey file?

Edit: I got a couple of helpful comments on my raspberrypi forum thread… Adding ‘disable_overscan=1’ to config.txt did the trick.

https://www.raspberrypi.org/forums/viewtopic.php?f=55&t=136395&p=908070#p908070

Trying to get the Pico RISC OS distro working on the Pi Zero and I have run into an impasse.

The Pi Zero requires latest firmware (Nov 2015) but the latest cut-down Pico RISC OS ROM is version 4 (Aug 2015) – so the Pi Zero starts up but then reports that the disc drive is empty (SDFS::0). If I replace it with a full ROM (but of course no FileCore partition and thus no &.!Boot directory) it sees the disc correctly (but boots into the desktop).

Any suggestions please? The same effect is seen if trying to get the Pico distro working on a model B+ which has a micro SD card so I assume that the version of RISC OS used in the Pico predates the lack of ‘card ready’ signal (which was present on earlier models with a full size SD card amd was used by RISC OS to say whether the drive was empty).

Yes, RISC OS Pico is “old” now – nearly a year old – “2015-03-08 16:09:51”.

I think we should have new versions of Pico when RISC OS itself changes for either an additional member of the Pi family or to cater for a firmware change.

Oh, and a quick hack to provide *Pointer and a pointer itself might be appreciated by some. ;-)

It’s older than that – the ROM image is RISC OS 5.21 (29-Apr-2014) whatever the date of the zip archive might say!

I’m looking at what’s needed to provide a pointer.

It’s older than that

Wow. That’s positively ancient.

I’m looking at what’s needed to provide a pointer.

You’ve probably already seen this. If not…
http://www.riscosopen.org/forum/forums/5/topics/3916#posts-50057

This will add a pointer:

   10REM >Pointer
   20DIM ptr% &120
   30REM Data for each line of pointer:
   40DATA 1,0,&14,0,&154,0,&5D0,0,&5F50,0,&57F40,0,&17FD00,0
   50DATA &17FFD00,0,&15FFF400,0,&5FFFD400,0,&7FFFD000,5
   60DATA &FFFF4000,&57,&FFFF4000,&15F,&FFFD0000,&57,&FFF50000,&15
   70DATA &7FF40000,5,&7FD00000,&D,&5FD00000,&3F,&17400000,&FC
   80DATA &5400000,&3F0,&1000000,&FC0,0,&3F00,0,&3FC00
   90DATA 0,&FF000,0,&3F0000,0,&FC0000,0,&3F00000
  100DATA 0,&FC00000,0,&3F000000,0,&FC000000,0,&30000000
  110DATA 0,0
  120FOR i%=12 TO &108 STEP 4
  130  READ a%
  140  ptr%!i%=a%
  150NEXT
  160ptr%?2=0
  170ptr%?3=1
  180ptr%?4=8:REM width in bytes
  190ptr%?5=32:REM height in lines
  200ptr%?6=0
  210ptr%?7=0
  220ptr%!8=ptr%+12
  230SYS "OS_Word",21,ptr%+2
  240*FX 106,1
  250END

It’s older than that – the ROM image is RISC OS 5.21 (29-Apr-2014) whatever the date of the zip archive might say!

The kernel on the micro SD card on my desk says 07-Feb-2015, which would sound about right compared with the products file unless ROOL have had a fat finger moment and copied an older ZIP file onto the downloads page. I’m not buying another one just to find out, there’s only so much MODE 7 I need.