This is part IV of a brief tutorial about the i.MX51′s SDMA core. The SDMA for other i.MX devices, e.g. i.MX25, i.MX53 and i.MX6 is exactly the same, with changes in the registers’ addresses and different chapters in the Reference Manual. This is by no means a replacement for reading the Reference Manual, but rather [...]
This is part III of a brief tutorial about the i.MX51′s SDMA core. The SDMA for other i.MX devices, e.g. i.MX25, i.MX53 and i.MX6 is exactly the same, with changes in the registers’ addresses and different chapters in the Reference Manual. This is by no means a replacement for reading the Reference Manual, but rather [...]
This is part II of a brief tutorial about the i.MX51′s SDMA core. The SDMA for other i.MX devices, e.g. i.MX25, i.MX53 and i.MX6 is exactly the same, with changes in the registers’ addresses and different chapters in the Reference Manual. This is by no means a replacement for reading the Reference Manual, but rather [...]
This is part I of a brief tutorial about the i.MX51′s SDMA core. The SDMA for other i.MX devices, e.g. i.MX25, i.MX53 and i.MX6 is exactly the same, with changes in the registers’ addresses and different chapters in the Reference Manual. Freescale’s Linux drivers for DMA also vary significantly across different kernel releases. It looks [...]
This is a small, but annoying thing about WordPress. They obviously didn’t consider the “0x” hexadecimal notation. What they did consider, was that if someone says “2x2″ that surely means “2 times 2″, so why not making that “x” in the middle fancy? Well, maybe because that makes “0x123″, which is a hexadecimal number, look [...]
It may help investigating the interrupt descriptors. For a 2.6.38 kernel, putting this in a kernel module load supplies some information (includes, declarations and code mixed below. Organize properly in your own module) #include <linux/irq.h> #include <linux/interrupt.h> #include <asm/irq.h> int i; struct irq_desc *desc; for_each_irq_desc(i, desc) { if (!desc) continue; printk(KERN_INFO “%d: status=%08x, chip=%08x, handle_irq=%08x\n”, [...]
What we have here As one can guess from my notes about the i.MX51′s external bus and the oscilloscope shots I’ve published, I made myself a small dissection kit for watching the bus’ lines activity with a digital oscilloscope. This is a good time to mention, that the kit was done quickly and dirty, so [...]
These are a few oscilloscope samples, some of which are pretty crude, showing Freescale’s i.MX51 accessing its address/data bus. I worked with an Armadeus APF51 board, which has a 16-bit multiplexed bus connected to the Xilinx Spartan-6 FPGA. The FPGA was used to wire bus signals to a pin header, so 1-2 ns skews between [...]
These are my notes as I made my way in grasping how the EIM bus works. Unfortunately, the information in the reference manual was far from complete, so except for the list of acronyms, this page consists of things I found out by reverse engineering the bus. The actual bus cycle outlines and timings are [...]
Scope This post was spun off the main post regarding setting up the Armadeus board for Embedded Linux on ARM and Xilinx Spartan-6 FPGA. It covers my own little war story as I set up the Buildroot SDK, so I could have my own cross compiler and Linux kernel to work with. As kernel.org happened [...]
