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by sean.lawless
Fri Jul 19, 2019 10:12 pm
Forum: Bare metal, Assembly language
Topic: Raspberry Pi 4
Replies: 59
Views: 6007

Re: Raspberry Pi 4

You are welcome. LPAE/MMU is needed for xHCI in any case in AArch32, because access to 0x600000000 (above 4 GB boundary) is needed. The Act LED is at GPIO42 on RPi 4. The base address of most peripherals, known from the BCM2835, is at 0xFE000000 on ARM side now. Thanks again, this is excellent info...
by sean.lawless
Fri Jul 19, 2019 7:20 am
Forum: Bare metal, Assembly language
Topic: Raspberry Pi 4
Replies: 59
Views: 6007

Re: Raspberry Pi 4

The kernel7l.img file does not really need to be LPAE enabled for bare-metal operation. You can take a normal non-LPAE-kernel image and rename it to kernel7l.img . LPAE only means, that the kernel can access memory locations above the 32-bit 4GB boundary. On the RPi 4 this is only needed for access...
by sean.lawless
Fri Jul 19, 2019 6:59 am
Forum: Bare metal, Assembly language
Topic: RPi 2 and OpenOCD
Replies: 25
Views: 12578

Re: RPi 2 and OpenOCD

I spent quite a bit of time trying to get GDB to work with RPi2 in this scenario but it never quite did. Could halt and use OpenOCD for debugging, but GDB was never really happy.
https://www.raspberrypi.org/forums/view ... D#p1477394
by sean.lawless
Wed Jul 17, 2019 11:26 pm
Forum: Bare metal, Assembly language
Topic: Raspberry Pi 4
Replies: 59
Views: 6007

Re: Raspberry Pi 4

For boot kernel execution, the RPi 4 will execute the new file kernel7l.img (lpae is enabled on RPi 4). If this file is not present on the boot partition Raspbian will not boot. For bare metal compiling with arm-none-eabi-gcc compiler, a kernel7.img file is not compatible; the Raspbian kernel7.img i...
by sean.lawless
Fri Jun 14, 2019 1:50 am
Forum: Bare metal, Assembly language
Topic: Openocd setup is OK but breakpoints are ignored..
Replies: 2
Views: 478

Re: Openocd setup is OK but breakpoints are ignored..

Did you try software breakpoints? Also, sharing your OpenOCD configuration file(s) might also help others see the problem, for example, what is causing the "unable to receive message" in the output you posted, this is an unfamiliar message to me.
by sean.lawless
Thu Jun 06, 2019 7:10 pm
Forum: Bare metal, Assembly language
Topic: OpenOCD BCM2835 GPIO JTAG bitbang driver
Replies: 0
Views: 539

OpenOCD BCM2835 GPIO JTAG bitbang driver

Thank you for having such a great forum to ask questions. Based on other online tutorials I created a procedure to use one RPi running Raspbian to act as a OpenOCD JTAG controller to debug a different RPi executing bare metal software. When I follow the procedure below, the OpenOCD BCM2835 GPIO JTAG...

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