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by adun
Fri Apr 27, 2018 8:59 am
Forum: Compute Module
Topic: WiFi chip for Compute Module 3
Replies: 22
Views: 19309

Re: WiFi chip for Compute Module 3

We discussed this also here Which Wifi/Bluetooth chip does the RPi 3 model B integrates?
Soc:
=====
GPIO 32-33 UART0 for BT
GPIO 34-38 SD1 for Wifi
GPIO 42 GPCLK1 for Ethernet 25MHz output
GPIO 43 GPCLK2 for Wifi 32kHz output

Port Expander
=============
GPIO 128 BT_ON
GPIO 129 WL_ON
by adun
Wed Apr 25, 2018 4:29 pm
Forum: Advanced users
Topic: Which Wifi/Bluetooth chip does the RPi 3 model B integrates?
Replies: 13
Views: 13176

Re: Which Wifi/Bluetooth chip does the RPi 3 model B integrates?

I found it thanks. Configuring the pull resistors on the FXL6408 on CM3 So those pins could directly be used by the firmware via dt-blob.bin for e.g. POWER_LOW. Could the CAM GPIOs be controlled from linux since they are only for ON/OFF and a CAM LEDs ? Basically, which functions are mandatory to be...
by adun
Wed Apr 25, 2018 3:42 pm
Forum: Advanced users
Topic: Which Wifi/Bluetooth chip does the RPi 3 model B integrates?
Replies: 13
Views: 13176

Re: Which Wifi/Bluetooth chip does the RPi 3 model B integrates?

Interesting information thank you !
So if the firmware would (also) need to access the port expander a custom option in the dt-blob would be necessary to let the firmware handle the external GPIOs like internal ones?
by adun
Wed Apr 25, 2018 3:16 pm
Forum: Advanced users
Topic: Which Wifi/Bluetooth chip does the RPi 3 model B integrates?
Replies: 13
Views: 13176

Re: Which Wifi/Bluetooth chip does the RPi 3 model B integrates?

Yes, I meant if you also add Wifi/BT togehter with Audio and I2C0 this would use most of the GPIOs from Bank 1. It will certainly be more expensive to replicate a 3+ this way but as mostly with a CM it's a form factor thing. Just curious about what you said of adding an own GPIO expander. If doing s...
by adun
Wed Apr 25, 2018 12:32 pm
Forum: Advanced users
Topic: Which Wifi/Bluetooth chip does the RPi 3 model B integrates?
Replies: 13
Views: 13176

Re: Which Wifi/Bluetooth chip does the RPi 3 model B integrates?

But there's no real reasons for a GPIO expander on the user side of the CM3 as you have all the GPIOs available. Choose one you like the look of and connect up to that (if needed). There is a GPIO expander on the CM3 as an I2C bus was required to the SMPS, so two lines bit-bash I2C to the SMPS and ...
by adun
Tue Apr 24, 2018 8:39 am
Forum: Advanced users
Topic: Which Wifi/Bluetooth chip does the RPi 3 model B integrates?
Replies: 13
Views: 13176

Re: Which Wifi/Bluetooth chip does the RPi 3 model B integrates?

What can be read out from the firmware dt-blob: Soc: ===== GPIO 32-33 UART0 for BT GPIO 34-38 SD1 for Wifi GPIO 42 GPCLK1 for Ethernet 25MHz output GPIO 43 GPCLK2 for Wifi 32kHz output Port Expander ============= GPIO 128 BT_ON GPIO 129 WL_ON Sadly the port expander GPIOs don't come through the SODI...
by adun
Wed Apr 18, 2018 2:10 pm
Forum: Compute Module
Topic: CM3 and I2C to MXL7704 PMIC
Replies: 5
Views: 783

Re: CM3 and I2C to MXL7704 PMIC

Thanks a lot for clearing this up.
So would I still have to use a GPIO for the firmware to detect undervoltage since the MXL7704 will only be controlled by linux ?
by adun
Wed Apr 18, 2018 12:25 pm
Forum: Compute Module
Topic: CM3 and I2C to MXL7704 PMIC
Replies: 5
Views: 783

CM3 and I2C to MXL7704 PMIC

Hi, If one would want to use the new MXL7704 PMIC on a custom CM carrier board how should the connection to the VC I2C bus be? The firmware is bitbashing I2C on GPIO 46/47 but those pins are not accessible on CM3. Can the MXL7704 be connected to two other GPIO pins and will there be an option to let...
by adun
Sun Apr 15, 2018 10:56 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: Push buttons - should I be using a resistor or not? (yes)
Replies: 24
Views: 65187

Re: Push buttons - should I be using a resistor or not? (yes)

If I recall correctly there were two push buttons (sw2 and sw3) on the Raspberry Pi alpha board connected to the GPIOs. If one could tell how they were wired up there we could do it the same way.
by adun
Sun Mar 25, 2018 12:43 pm
Forum: Compute Module
Topic: Faster LAN via RasPi 3B+ LAN chip?
Replies: 11
Views: 2491

Re: Faster LAN via RasPi 3B+ LAN chip?

The only information about the LAN7515 chip I could find was the microchip product compare page for LAN7515/LAN9514 https://www.microchip.com/wwwproducts/ProductCompare/LAN7515/LAN9514 Additionally, the given specs about the LAN7515 chip are a bit confusing. In the description they mention: USB 2.0 ...
by adun
Mon Mar 19, 2018 12:51 pm
Forum: Advanced users
Topic: RPI 3B+ backpowering protection circuit
Replies: 1
Views: 666

RPI 3B+ backpowering protection circuit

By looking at the reduced schematics of the 3B+ if saw that compared to the 3B the backpowering circuit has been removed.
Is there any reason why this was done? Is there now no “ideal diode” protection anymore?
https://raw.githubusercontent.com/raspb ... ircuit.png
by adun
Sun May 15, 2016 8:04 pm
Forum: General discussion
Topic: A picture from The Pi Hut
Replies: 283
Views: 46121

Re: A picture from The Pi Hut

gregeric wrote:Looks real enough to me, and matches what I see in firmware.
How did you get that? The firmware dt-blob.dts on github has not yet been updated.
Did you decompile the firmware .ELF file ?
by adun
Sat Apr 16, 2016 8:58 pm
Forum: Compute Module
Topic: Compute Module 3 Cluster
Replies: 19
Views: 18721

Re: Compute Module 3 Cluster

Interesting project!
The communication beetwen the CMs is done over ethernet right. What speed benefit do you get from using GIGe controller? As it goes still over the USB 2 port.
And what does the board management controller CM exactly do?
by adun
Sat Apr 16, 2016 8:47 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: More than 2 SPI slaves on RPI3
Replies: 7
Views: 3695

Re: More than 2 SPI slaves on RPI3

With current bcm2835 driver you can use any other GPIO as additional chip select pins without needing additional hardware. You simply have to write an overlay to enable the additional CS pins. I've made an overlay for SPI0 for the miscap pHAT for the Pi-Zero, where GPIO 5 and 6 are enabled as CE3 an...
by adun
Tue Apr 12, 2016 5:37 pm
Forum: Advanced users
Topic: Pi 3 sata controller
Replies: 21
Views: 80240

Re: Pi 3 sata controller

A right that's why it's marked as CCP2TX.
I got ball data from the elinux.org and the connections from the CM schematics. Of course it might contain errors.
Image
by adun
Tue Apr 12, 2016 3:43 pm
Forum: Advanced users
Topic: Pi 3 sata controller
Replies: 21
Views: 80240

Re: Pi 3 sata controller

Very interesting, thanks 6by9 (Yes, the balls for the CCP2TX will be there somewhere under BCM283[5|6|7], but I very much doubt they'll ever be routed out, even on the Compute Module. I'm expecting that they're dedicated connections too, so no options for muxing them) I dont know if some of the "und...
by adun
Tue Apr 12, 2016 12:26 pm
Forum: Advanced users
Topic: Pi 3 sata controller
Replies: 21
Views: 80240

Re: Pi 3 sata controller

The host port is primarily a slave port. It requires external processor attention to read/write data to/from BCM2835. In theory you could use FPGA glue to come up with a bidirectional data path, but adding any sort of decent-speed FPGA puts 10s of dollars of cost on a board. SMI Linux drivers are a...
by adun
Mon Apr 11, 2016 7:32 pm
Forum: General discussion
Topic: voltage and current sensors
Replies: 7
Views: 2839

Re: voltage and current sensors

I suggest you use a mcp3422 adc that will be attached to the Pi's i2c bus. there is a good reference design in the datasheet for using mcp3422 as a battery gauge. Basically you use a voltage divider to get the voltage and measure the voltage drop over a very small resistor where you can calculate th...
by adun
Sun Apr 10, 2016 11:36 pm
Forum: Advanced users
Topic: Pi 3 sata controller
Replies: 21
Views: 80240

Re: Pi 3 sata controller

Actually there are two fast data buses on the soc. SMI: The pins are available on the GPIO header as alt function. As mikronauts has mentioned there is still no documentation available for it. However an overlay exists to talk to NAND flash https://github.com/raspberrypi/linux/blob/rpi-4.1.y/arch/ar...
by adun
Sun Apr 10, 2016 11:00 pm
Forum: HATs and other add-ons
Topic: Miscap - PiZero Ethernet pHAT
Replies: 86
Views: 21632

Re: Miscap - PiZero Ethernet pHAT

dtparam=i2c_vc=on is to get acces to i2c0 from userspace. This means that i2c0 is now controlled by ARM no longer by the GPU (firmware) as it usually is. You can safely remove this line after the code is written to the eeprom. The firmware loads the stuff from the eeprom during boot by muxing i2c0 ...
by adun
Sat Apr 09, 2016 9:03 pm
Forum: HATs and other add-ons
Topic: Miscap - PiZero Ethernet pHAT
Replies: 86
Views: 21632

Re: Miscap - PiZero Ethernet pHAT

Nice to hear that everything is working ;)
The tutorial you made is very good, also for general information how HAT eeprom works.
If the additional SPI0 CS are no longer needed for the final version, I can remove them from the code as those were just for testing.
by adun
Wed Apr 06, 2016 5:00 pm
Forum: General discussion
Topic: Schematics of Raspberry Pi 3 Model B
Replies: 28
Views: 19326

Re: Schematics of Raspberry Pi 3 Model B

Partial schematics of RPi3 Rev1.2 are now available:
https://www.raspberrypi.org/documentati ... EDUCED.pdf.
Too bad the part about the port expander is missing.
by adun
Tue Apr 05, 2016 11:15 am
Forum: Compute Module
Topic: USB Gadget Mode on Compute Module
Replies: 12
Views: 5165

Re: USB Gadget Mode on Compute Module

On Pi Zero the USB OTG pin is connected to the micro USB port. On CM the OTG pin is accessible on the GPIO bank where it can be tied to ground. Usually if a external USB device pulls this signal to GND, then the OTG controller will switch to Host mode. If this signal is floating when the external US...
by adun
Mon Mar 28, 2016 3:15 pm
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: I2C mulitplexer support
Replies: 62
Views: 13830

Re: I2C mulitplexer support

I So address 0x50 and the mux address are not available on any of the virtual busses - there's no way around that one. (The camera and display are on different GPIOs, so you already effectively have a mux there controlled by the GPU). I understand, that's because they are on the bus before the mux ...
by adun
Mon Mar 28, 2016 9:58 am
Forum: Interfacing (DSI, CSI, I2C, etc.)
Topic: I2C mulitplexer support
Replies: 62
Views: 13830

Re: I2C mulitplexer support

Nice to see it is working! The adafruit board has 10k pull up resistors on the i2c lines. On GPIO 0,1 with the 3k9 from a attached HAT this will result in approximate 2k8 ohm what is lower than the recommended for the HAT EEPROM. On compute module the i2c0 line for CSI/DSI has 1k8 pull ups. What wou...

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