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by LukeW
Sat Jan 23, 2021 12:29 am
Forum: General
Topic: Names when multiple pico boards are connected
Replies: 1
Views: 81

Re: Names when multiple pico boards are connected

No, all RP2040s are identical, and the bootloader is etched permanently into the chip. Generally not too confusing as you're only programming one board at a time (or at least that is all my brain can manage)
by LukeW
Fri Jan 22, 2021 8:48 pm
Forum: General
Topic: [Confirmed] UF2 programming
Replies: 13
Views: 374

Re: UF2 programming

Never thought to try this, but yes your mental model is correct as far as I know :D

This gives me a blinky light:

Code: Select all

$ make blink
$ umount /dev/sda1
$ sudo bash -c "cat blink/blink.uf2 > /dev/sda1"
by LukeW
Fri Jan 22, 2021 7:35 pm
Forum: General
Topic: Why does the RP2040 processor have dual cores?
Replies: 35
Views: 991

Re: Why does the RP2040 processor have dual cores?

I'd like to think in a small company like RPT that the hardware group do ask for opinions on hardware choices from the software people and don't just throw the finished design over the wall and say "program that". One thing we do that is quite unusual is we force hardware engineers to wri...
by LukeW
Fri Jan 22, 2021 12:53 pm
Forum: General
Topic: Oddities in PIO section of manual
Replies: 21
Views: 567

Re: Oddities in PIO section of manual

Also on page 325 is the same example code twice and without any identifier like "example x.yz" (which would allow the text to refer to it twice without it appearing twice) Good point, doesn't flow well and as you say causes unnecessary confusion. Will caption the first instance and replac...
by LukeW
Fri Jan 22, 2021 12:39 pm
Forum: General
Topic: Oddities in PIO section of manual
Replies: 21
Views: 567

Re: Oddities in PIO section of manual

But that doesn't really make sense. I would want as follows: wait for TX FIFO data assert a 0 on TX line (start bit) shift out data assert a 1 on TX line (stop bit) Why would I use IFEMPTY for that instead of BLOCK? Well the short answer is that I hadn't used that particular side set trick when I w...
by LukeW
Thu Jan 21, 2021 11:36 am
Forum: General
Topic: precision timer for external event capture
Replies: 1
Views: 135

Re: precision timer for external event capture

You could write a PIO program like this: .program measure_pulse mov x, ~null wait 1, pin 0 loop: jmp x-- next next: jmp pin loop mov isr, ~x push (note this is a sketch, I haven't tried this). This would measure the width of every pulse it sees, with a resolution of 2 clock cycles (2 x 8 ns for defa...
by LukeW
Thu Jan 31, 2019 11:52 am
Forum: General discussion
Topic: RISC-V
Replies: 131
Views: 20660

Re: RISC-V

As far as I can see the visible ISA is just the tip of the iceberg as far as the complexity of the CPU is concerned. ISA and microarchitecture are separate, but ISA has significant impact on how cheaply and effectively you can implement the microarchitectural features you mentioned. For example, pa...
by LukeW
Thu Jan 31, 2019 10:54 am
Forum: General discussion
Topic: RISC-V
Replies: 131
Views: 20660

Re: RISC-V

I have no idea why 'ld' got terminated; I had just left it running. It's eaten up 5.6GB since starting but plenty free. Out of memory ? I don't know. Another one to add to the ever growing 'didn't work' list. Does anyone have instructions for building any RISC-V compiler on a Pi 3B which they know ...
by LukeW
Wed Jul 18, 2018 6:09 pm
Forum: Device Tree
Topic: Connecting external raw nand using GPIO - RPI3b
Replies: 16
Views: 9912

Re: Connecting external raw nand using GPIO - RPI3b

SMI has a 6 bit "address" bus (SA0 to SA5), which I think is misnamed. These pins idle high in between transactions, and seem to be useful mainly for enables, not addresses. This is what they are used for in the SMI NAND driver, which is a small shim sitting between Linux's MTD (NAND) stac...
by LukeW
Mon Jul 11, 2016 4:29 pm
Forum: General programming discussion
Topic: SMI Documentation ?
Replies: 17
Views: 9982

Re: SMI Documentation ?

Thought I'd reply to this old thread as it is the first result on google, so other people may come here too, looking for info. There is now an SMI driver -- see these commits: https://github.com/raspberrypi/linux/commit/e19c303e7d54d986e0bd3e47107a83e30329c1d0 https://github.com/raspberrypi/linux/co...
by LukeW
Sat Aug 22, 2015 9:22 pm
Forum: C/C++
Topic: Build tools that exploit quad core CPUs
Replies: 10
Views: 2589

Re: Build tools that exploit quad core CPUs

No, the minimum for GPU memory is 16. The GPU is responsible for some initial setup.
by LukeW
Thu Jul 23, 2015 2:05 pm
Forum: Raspberry Pi OS
Topic: Bluetooth Manager
Replies: 1
Views: 2787

Re: Bluetooth Manager

As an alternative to running as root, you can consider adding your username to the group "bluetooth" to get the required permissions.

e.g.

Code: Select all

sudo adduser pi bluetooth
For username "pi".
by LukeW
Tue Jul 07, 2015 3:39 pm
Forum: Compute Module
Topic: SDIO for Wifi/Bluetooth module
Replies: 94
Views: 53176

Re: SDIO for Wifi/Bluetooth module

Thank you Phil! I think I pulled the file from the 4.0 repo a couple of weeks ago.
by LukeW
Tue Jul 07, 2015 2:47 pm
Forum: Compute Module
Topic: SDIO for Wifi/Bluetooth module
Replies: 94
Views: 53176

Re: SDIO for Wifi/Bluetooth module

Sorry for resurrecting an old thread, but I thought it would be useful to add some information. SDIO is supported by the mmc (SD1) driver. In order to use SD1 for SDIO, you'll need to use SD0 (sdhost) for booting, as SD1 is currently being used for this. Phil has written a device tree overlay which ...

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