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by gregeric
Sun Apr 16, 2017 9:59 pm
Forum: General discussion
Topic: Future Pi Zero W Suggestion
Replies: 93
Views: 8195

Re: Future Pi Zero W Suggestion

You can feed the Pi ZeroW with around 2.9V directly from eg a LiPo, and it will still function, so long as no 5V dependant peripherals are attached.
by gregeric
Sun Apr 16, 2017 9:01 pm
Forum: General discussion
Topic: Future Pi Zero W Suggestion
Replies: 93
Views: 8195

Re: Future Pi Zero W Suggestion

jamesh wrote:Camera socket added a few pennies
You guys must have gotten a good deal on the cost of the connector! Of all the stunts RPi have pulled, aside from the $5 Zero itself, adding the camera connector whilst keeping the $5 price srtill impresses me most.
by gregeric
Sat Apr 15, 2017 5:41 pm
Forum: Off topic discussion
Topic: pi zero w with dsi connector - thoughts/opinions/reasons
Replies: 19
Views: 6843

Re: pi zero w with dsi connector - thoughts/opinions/reasons

Currently, there's only one screen you can attach to the DSI connector, and it's a big one. The form factor of the Zero is wasted on the 7" panel - you can hide any Pi model behind that, including the CM/CMIO board, the biggest of the lot. Until such time as there's a 65x30mm DSI panel, and supporte...
by gregeric
Fri Apr 14, 2017 9:52 pm
Forum: Other projects
Topic: How to use Raspberry as a USB keyboard repeater
Replies: 2
Views: 575

Re: How to use Raspberry as a USB keyboard repeater

The Pi3 isn't appropriate here - it's USB host only, thus cannot act as a HID/Keyboard.

Two x Pi Zero(W) is what you want, one attached to each Mac.

You'll need some means of connecting the Zeros (network, bluetooth, GPIO) so they both send the same "play" etc keyboard event on that button press.
by gregeric
Fri Apr 14, 2017 7:44 am
Forum: Compute Module
Topic: CM3 Release Date
Replies: 32
Views: 7844

Re: CM3 Release Date

by gregeric
Thu Apr 13, 2017 8:23 pm
Forum: General discussion
Topic: Idea for RP silk screen
Replies: 18
Views: 1759

Re: Idea for RP silk screen

Nice idea! They change the (bottom) silkscreen every couple of weeks anyways, updating the PCB production date stamp - why not add a nugget of a quote?
by gregeric
Wed Apr 12, 2017 12:03 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Add an I2S mic using device tree & simple-audio-card
Replies: 37
Views: 27124

Re: Add an I2S mic using device tree & simple-audio-card

One difference I can see on looking at the datasheets is that the Knowles mic appears to output its data one half a bit clock earlier, 180° out of phase (starting on a CLK high, not low like the Invensys mic). I only have Invensys ICS43432 mics, so cannot do any further comparisons.
by gregeric
Tue Apr 11, 2017 10:53 pm
Forum: General discussion
Topic: Turning on Zero W every hour
Replies: 46
Views: 13030

Re: Turning on Zero W every hour

For an RTC I would recommend the mcp7940n-i/sn from microchip. The MCP794xx series are supported as a wakeup-source by the Pi's i2c-rtc overlay. Unfortunately, the upstream driver needs a patch to make the wakealarm sysfs entry writable. I've submitted a simple patch to allow that. Saves you having...
by gregeric
Tue Apr 11, 2017 10:49 am
Forum: General discussion
Topic: Turning on Zero W every hour
Replies: 46
Views: 13030

Re: Turning on Zero W every hour

Whether rtcwake will work with a DS3231 on Raspbian/Jessie - I don't know. rtcwake doesn't work, but the ds3231 works well as a wakeup-source with current Jessie. In config.txt, dtoverlay=i2c-rtc,ds3231,wakeup-source Clear current alarm & set new one with: sudo sh -c "echo 0 > /sys/class/rtc/rtc0/w...
by gregeric
Tue Apr 04, 2017 3:47 pm
Forum: Compute Module
Topic: bcm4339 with rasberry pi 3 (SDIO)
Replies: 4
Views: 2641

Re: bcm4339 with rasberry pi 3 (SDIO)

Sounds like all the steps are correct to me. Do you see any reference to mmc1 in your kernel logs ie dmesg | grep mmc1? Anything reported by dmesg | grep brcm?
by gregeric
Tue Apr 04, 2017 12:50 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Add an I2S mic using device tree & simple-audio-card
Replies: 37
Views: 27124

Re: Add an I2S mic using device tree & simple-audio-card

I'd guess you have LRCLK & BCLK swapped. I don't have such a module, but here's how I'd wire it:

LRCLK -> FS (BCM19, pin 35)
BCLK -> CLK (BCM18, pin 12)
DOUT -> DIN (BCM20, pin 38)

Then ground SEL, connect GND & 3V to the Pi's GND & 3V3.
by gregeric
Sat Apr 01, 2017 6:21 am
Forum: Compute Module
Topic: cm/cm3 boot-time configuration
Replies: 8
Views: 1404

Re: cm/cm3 boot-time configuration

The eeprom is polled by the GPU firmware & very early in the boot process: before the rainbow splash screen is rendered, you can see a train of pulses lasting ~3.5ms, even without an eeprom on your expansion board. Enabling kernel/arm i2c use does not enact it. You can just as well configure your ha...
by gregeric
Fri Mar 31, 2017 11:08 am
Forum: Advanced users
Topic: Difference between DWCOTG and DWC2
Replies: 2
Views: 3870

Re: Difference between DWCOTG and DWC2

dwc_otg is the driver that has been heavily patched to squeeze most performance & function in host mode on the Pi: the fiq stuff etc. So heavily patched that, despite the name, it only does host mode & not OTG. dwc2 is an upstream driver which can do the OTG host/gadget flip dictated by OTG_SENSE. I...
by gregeric
Thu Mar 30, 2017 7:57 pm
Forum: Troubleshooting
Topic: Pi Zero W as unintended 5GHz jammer?
Replies: 2
Views: 1557

Re: Pi Zero W as unintended 5GHz jammer?

No such goings on here - I have ZeroW's connected to a 2.4GHz hotspot in the vicinity of a 5GHz hotspot & connected devices. There again, I don't have an MS Surface Pro, only Motorola Moto-X to test with.

Surely any such "jamming" issues would have been picked up in the FCC testing?
by gregeric
Thu Mar 30, 2017 10:49 am
Forum: Off topic discussion
Topic: Did I just take a picture of Zero W WiFi signal?
Replies: 12
Views: 3837

Re: Did I just take a picture of Zero W WiFi signal?

The wiggly line is not present in the original photo. It seems to have been introduced in the edit process. Can you reproduce it, repeating the same image manipuluations?
by gregeric
Thu Mar 30, 2017 8:58 am
Forum: Off topic discussion
Topic: Did I just take a picture of Zero W WiFi signal?
Replies: 12
Views: 3837

Re: Did I just take a picture of Zero W WiFI signal?

I think your cat jumped on your mouse whilst your back was turned.

Kinda cute how it looks like the wiggles you draw in Feynman diagrams for photons. One clever cat!
by gregeric
Tue Mar 28, 2017 11:45 pm
Forum: General discussion
Topic: Using external pull down resistor board?
Replies: 4
Views: 1130

Re: Using external pull down resistor board?

Yes, the Zero is the same as others: 0-8 pulled high, 9-27 pulled low. If possible, choose your GPIOs so that your desired initial pull is the default one - the device tree stuff may take a second or so to become active. Failing that, install your stronger pull resistor either directly on the Pi or ...
by gregeric
Tue Mar 28, 2017 10:23 am
Forum: General discussion
Topic: Using external pull down resistor board?
Replies: 4
Views: 1130

Re: Using external pull down resistor board?

Also, only GPIOs 28,29 44 & 45 float. 0-8 have default internal 50k pulls high, the rest default pull low. Additionally, there are strong pulls up for whichever I2C peripheral appears at pins 3 & 5 on the GPIO header (GPIOs 2&3 on the majority of Pi models). The pulls on 28, 29, 44 & 45 are already ...
by gregeric
Mon Mar 27, 2017 6:14 pm
Forum: Beginners
Topic: ds3231 clock temperature sensor access?
Replies: 11
Views: 1938

Re: ds3231 clock temperature sensor access?

So, to build only the required rtc-ds1307.ko to get DS3231 temperature support in kernels <4.6. Firstly, get kernel header files: sudo apt-get update && sudo apt-get dist-upgrade sudo apt-get install -y raspberrypi-kernel-headers sudo reboot After reboot, mkdir ds1307 cd ds1307 wget https://raw.gith...
by gregeric
Mon Mar 27, 2017 4:06 pm
Forum: Beginners
Topic: ds3231 clock temperature sensor access?
Replies: 11
Views: 1938

Re: ds3231 clock temperature sensor access?

Build the module alone, not the entire kernel. I have a simple recipe for that, will post it later.
by gregeric
Mon Mar 27, 2017 3:46 pm
Forum: Beginners
Topic: ds3231 clock temperature sensor access?
Replies: 11
Views: 1938

Re: ds3231 clock temperature sensor access?

Or, cherry pick the newer rtc-ds1307.c source and build & replace rtc-ds1307.ko. That's what i did. Let me know if you need a quick run down on that.
by gregeric
Mon Mar 27, 2017 3:09 pm
Forum: Beginners
Topic: ds3231 clock temperature sensor access?
Replies: 11
Views: 1938

Re: ds3231 clock temperature sensor access?

DS3231 temperature sensor readout is in kernels >=4.6 AFAICR
by gregeric
Mon Mar 27, 2017 1:16 pm
Forum: Graphics, sound and multimedia
Topic: Raspberry PI Zero (W) - Why no audio???
Replies: 12
Views: 8415

Re: Raspberry PI Zero (W) - Why no audio???

Get one of these £3 stereo BT audio receivers with built in amp: http://www.ebay.co.uk/itm/3W-3W-Wireless-Bluetooth-4-0-Audio-Receiver-Steady-Digital-Amplifier-Board-/311747989169?hash=item4895a0ceb1:g:nTMAAOSw4GVYOBC4 It adds nothing to the size of the ZeroW. Instead, mount it inside your speaker e...
by gregeric
Sun Mar 26, 2017 9:30 pm
Forum: General discussion
Topic: dual chip pi
Replies: 19
Views: 3736

Re: dual chip pi

The questions you raise are easy to pose, but difficult to answer. Those of us who have grown up with more simple compute platforms have a good understanding of how memory & cpu are connected, and what is possible, or not, and why it seems daft to ask such questions. The Raspberry Pi is a cheap devi...
by gregeric
Fri Mar 24, 2017 9:08 pm
Forum: General discussion
Topic: dual chip pi
Replies: 19
Views: 3736

Re: dual chip pi

fruit, I think you are overlooking that the poster is possibly somewhat further down the age & learning scales than you. Your posts serve only to extinguish their enthusiasm before it has had chance to blossom. Rather than mocking, try sharing your knowledge.

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