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by adun
Sun Mar 27, 2016 7:43 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: I2C mulitplexer support
Replies: 62
Views: 14673

Re: I2C mulitplexer support

That's exactly what I was thinking of, thanks for explanation ! The only downside is that the main i2c0 interface will see the HAT EEPROM, but there's not much you can do to avoid that when that is the primary use for those GPIOs. This should not be a big problem as other devices will then be attach...
by adun
Sun Mar 27, 2016 6:51 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: I2C mulitplexer support
Replies: 62
Views: 14673

Re: I2C mulitplexer support

Correct me if I'm wrong The firmware does pin muxing beetween GPIO 0,1 HAT GPIO 44,45 Cam, Display GPIO 46,47 Port Expander, SMPS I think the idea of OP was to connect the mux to one of those pins (GPIO 0,1 on RPi3 as they are the only ones direct accessible). Then the firmware could treat the mux l...
by adun
Sun Mar 27, 2016 5:38 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: I2C mulitplexer support
Replies: 62
Views: 14673

Re: I2C mulitplexer support

Interesting idea. If I understand you correctly you want to connect the mux to the i2c0 port to add multiple i2c hosts along with the native i2c1. Currently on RPi3 i2c0 is not accessible by the ARM and reserved by the GPU for cam/disp, port expander and smps control. For the mux the firmware would ...
by adun
Thu Mar 24, 2016 1:13 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: I2C mulitplexer support
Replies: 62
Views: 14673

Re: I2C mulitplexer support

Thanks for the explanation .
Basically I was only after level shifting and intended to have the EN lines unconnected.
However if needed, the port control by I2C commands is a much better approach as the GPIO solution needs additional config/wiring and is not easy portable.
by adun
Thu Mar 24, 2016 11:49 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: I2C mulitplexer support
Replies: 62
Views: 14673

Re: I2C mulitplexer support

Is there any advantage in using this I2C multiplexer over a simpler I2C HUB PCA9518A that I was planning to use ?
by adun
Wed Mar 16, 2016 9:43 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: SPI SD Card
Replies: 5
Views: 1741

Re: SPI SD Card

Hi
Yes you are right. In your circuit the CLK/CS line are completly free from any external load.
Thanks again.

Image
by adun
Tue Mar 15, 2016 8:22 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: SPI SD Card
Replies: 5
Views: 1741

Re: SPI SD Card

I added a dual buffer with schmitt trigger inputs the following way.
Image
by adun
Tue Mar 15, 2016 6:51 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: SPI SD Card
Replies: 5
Views: 1741

Re: SPI SD Card

Ok thanks for the useful hints :)
So I will add a two channel buffer to CS/CLK line.
by adun
Tue Mar 15, 2016 12:13 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: SPI SD Card
Replies: 5
Views: 1741

SPI SD Card

For an additional SD Card slot using SPI I want to add an activity LED and came up with the following circuit. Is it safe to connect the card slot and the LED directly to the SPI bus like that or should I use a buffer beetween them. I don't use a pull up resistor for the CS line as the SD Card has a...
by adun
Tue Mar 15, 2016 9:45 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: More than 2 SPI slaves
Replies: 19
Views: 8841

Re: More than 2 SPI slaves

The current spi-bcm2835 driver supports additional GPIO chip-selects. For driver performance the hardware chip-select pins (CE0,CE1) will be automatically converted to GPIO CS's pins.
by adun
Tue Mar 08, 2016 9:08 am
Forum: General discussion
Topic: Schematics of Raspberry Pi 3 Model B
Replies: 28
Views: 20106

Re: Schematics of Raspberry Pi 3 Model B

Just wanted to update this too ;)
From this thread it seems that i2c0 is now also used for SMPS control
by adun
Fri Mar 04, 2016 10:27 pm
Forum: General discussion
Topic: Datasheet/schematics Raspberry pi V3
Replies: 4
Views: 911

Re: Datasheet/schematics Raspberry pi V3

He mentioned that in an issue on github raspberrypi/documentation
https://github.com/raspberrypi/documentation/issues/321
These are good news
by adun
Wed Mar 02, 2016 2:56 pm
Forum: General discussion
Topic: Schematics of Raspberry Pi 3 Model B
Replies: 28
Views: 20106

Re: Schematics of Raspberry Pi 3 Model B

I'm pretty sure on RPi3 the ACT LED was moved to the GPIO expander like the the ones for the camera.
That's why it appears on a virtgpio

Code: Select all

+&leds {
+	act_led: act {
+		label = "led0";
+		linux,default-trigger = "mmc0";
+		gpios = <&virtgpio 0 0>;
+	};
+};
by adun
Wed Mar 02, 2016 1:43 pm
Forum: General discussion
Topic: Schematics of Raspberry Pi 3 Model B
Replies: 28
Views: 20106

Re: Schematics of Raspberry Pi 3 Model B

With B+ this GPIO was already available on P40 header
by adun
Wed Mar 02, 2016 11:33 am
Forum: General discussion
Topic: Schematics of Raspberry Pi 3 Model B
Replies: 28
Views: 20106

Re: Schematics of Raspberry Pi 3 Model B

That's strange. I hope we get soon some official input about that.
GPIO 46,47 can also be used for I2C0 (ALT0). Probably the firmware has reserved those pins.
Btw GPIO 42: GPCLK1 must be the 25 MHz clock for the LAN9514
by adun
Wed Mar 02, 2016 11:25 am
Forum: General discussion
Topic: Schematics of Raspberry Pi 3 Model B
Replies: 28
Views: 20106

Re: Schematics of Raspberry Pi 3 Model B

HDMI hotplug should still be on GPIO 46.
Assuming that GPIO 0,1 ALT0 are still for HATs and GPIO 44,45 ATL1 for csi/dsi they are controlled by GPU not CPU.
So I don't know if you can see those gpio turned to ALT from userspace.
by adun
Wed Mar 02, 2016 11:14 am
Forum: General discussion
Topic: Schematics of Raspberry Pi 3 Model B
Replies: 28
Views: 20106

Re: Schematics of Raspberry Pi 3 Model B

The USB switch is pretty much what I expected as a variant on the B+/2B. Two comments: Is R_LIM on the USB switch not set by a single R50, 19.5kOhm? Does PTRCTRL2 go to the FAULT_N input, not USB_VBUS? Yes you are right, thanks. Of cource PTRCTRL2 goes to FAULT_N and R_LIM is one single resistor. T...
by adun
Wed Mar 02, 2016 10:48 am
Forum: General discussion
Topic: Schematics of Raspberry Pi 3 Model B
Replies: 28
Views: 20106

Re: Schematics of Raspberry Pi 3 Model B

I've made some schematics how I think the circuits schould be: CVBS / PWM Audio http://pixelbanane.de/yafu/3011253659/RPI3_AV.jpg USB Current Limit Circuit http://pixelbanane.de/yafu/1420371059/RPI3_CL.jpg Please report any error or confirm for correctness ;) PS: I think GPIO 44,45 are now used for ...
by adun
Wed Mar 02, 2016 10:14 am
Forum: General discussion
Topic: The Raspberry Pi 3 Model B Q&A thread
Replies: 457
Views: 207533

Re: The Raspberry Pi 3 Model B Q&A thread

gregeric wrote:
adun wrote:Even the act led has moved to a virtgpio. I assume they needed GPIO 47 again for sd-card detect. As the pi can now boot directly from usb / pxe.
I started a new thread on RPi3B schematics for us to tease this all out: viewtopic.php?f=63&t=138280
Good idea ;)
by adun
Wed Mar 02, 2016 9:39 am
Forum: General discussion
Topic: Sense HAT wiring help-What GPIO pins go where?
Replies: 9
Views: 2623

Re: Sense HAT wiring help-What GPIO pins go where?

Sense HAT needs:
GPIO 2,3 (I2C1) for all the sensors
GPIO 8-11 (SPI0) for programming the firmware using ISP. You could leave those pins.
GPIO 23, 24 for the joystick.
And power of course.
by adun
Wed Mar 02, 2016 9:32 am
Forum: General discussion
Topic: The Raspberry Pi 3 Model B Q&A thread
Replies: 457
Views: 207533

Re: The Raspberry Pi 3 Model B Q&A thread

Would be good if did not have to spend time searching for this info.. but thanks for confirmation ;) Where's the fun in that? As adun has noticed, they ran out of GPIOs so something had to give! Even the act led has moved to a virtgpio. I assume they needed GPIO 47 again for sd-card detect. As the ...
by adun
Mon Feb 29, 2016 3:59 pm
Forum: General discussion
Topic: The Raspberry Pi 3 Model B Q&A thread
Replies: 457
Views: 207533

Re: The Raspberry Pi 3 Model B Q&A thread

I'm very interested in what the GPIOs are used for. Is there a chance we get a list to see what has changed regarding B+ B2 ? Especially for the BT/WIFI Full Pi 3 pin-mapping can be seen in bcm2710-rpi-3-b.dts over here: https://github.com/raspberrypi/linux/commit/02ce9572cc77c65f49086bbc4281233bd3...
by adun
Mon Feb 29, 2016 10:43 am
Forum: General discussion
Topic: The Raspberry Pi 3 Model B Q&A thread
Replies: 457
Views: 207533

Re: The Raspberry Pi 3 Model B Q&A thread

I'm very interested in what the GPIOs are used for.
Is there a chance we get a list to see what has changed regarding B+ B2 ?
Especially for the BT/WIFI
by adun
Sat Feb 27, 2016 1:27 pm
Forum: HATs and other add-ons
Topic: SHABPi - SDIO WiFi for Pi Zero
Replies: 7
Views: 9502

Re: SHABPi - SDIO WiFi for Pi Zero

A good to know ;)
Btw is the compute module using the Arasan sdio interface for its emmc ?
by adun
Sat Feb 27, 2016 1:01 pm
Forum: HATs and other add-ons
Topic: SHABPi - SDIO WiFi for Pi Zero
Replies: 7
Views: 9502

Re: SHABPi - SDIO WiFi for Pi Zero

Really great work :)
Have you also tested to use your sd card socket along with the uSD card of the Pi Zero?
As far as I know the SD interface is used (on GPIO 48-53) and can't be redirected to GPIO 22-27.

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