diff --git a/books/beaglebone-cookbook/11misc/figures/boot-modes.png b/books/beaglebone-cookbook/11misc/figures/boot-modes.png new file mode 100644 index 0000000000000000000000000000000000000000..3acf99651239aab91c7988ec6e7f05c916539f3d Binary files /dev/null and b/books/beaglebone-cookbook/11misc/figures/boot-modes.png differ diff --git a/books/beaglebone-cookbook/11misc/figures/bootstrap.png b/books/beaglebone-cookbook/11misc/figures/bootstrap.png new file mode 100644 index 0000000000000000000000000000000000000000..f7c245d1fa0fc277257ceafbe5d8ae8fa3b9a6ac Binary files /dev/null and b/books/beaglebone-cookbook/11misc/figures/bootstrap.png differ diff --git a/books/beaglebone-cookbook/11misc/figures/init-process.png b/books/beaglebone-cookbook/11misc/figures/init-process.png new file mode 100644 index 0000000000000000000000000000000000000000..4b6570a8e4099acd0f49dbf0935c17763ddb8232 Binary files /dev/null and b/books/beaglebone-cookbook/11misc/figures/init-process.png differ diff --git a/books/beaglebone-cookbook/11misc/figures/pin-mapping.png b/books/beaglebone-cookbook/11misc/figures/pin-mapping.png new file mode 100644 index 0000000000000000000000000000000000000000..34e1b7755959346d34d55cfcda4426b97955afc7 Binary files /dev/null and b/books/beaglebone-cookbook/11misc/figures/pin-mapping.png differ diff --git a/books/beaglebone-cookbook/11misc/misc.rst b/books/beaglebone-cookbook/11misc/misc.rst index bb7c0eb5427e20bf7046b96ab717b476c91b4761..ff04c920495d6c49c86ebbc72f698856c484388f 100644 --- a/books/beaglebone-cookbook/11misc/misc.rst +++ b/books/beaglebone-cookbook/11misc/misc.rst @@ -624,3 +624,43 @@ By default, *P9_14* is set as an input. Switch it to an output and turn it on: The LED turns on when a *1* is written to *value* and turns off when a *0* is written. + +Notes on the boot sequence +========================== + +Here are some notes on what the BeagleBoard Play does when it boots up. Many of the booting +details come from the AM62x Technical Reference Manual +(https://www.ti.com/product/AM625, https://www.ti.com/lit/pdf/spruiv7). Page 2456 shows +the Initialization Process. + +.. figure:: figures/init-process.png + :align: center + :alt: Initialization Process + + Initialization Process + +We are interested in what happens in the **ROM code**. +Page 2457 shows the different ROM Bode Boot Modes. + +.. figure:: figures/boot-modes.png + :align: center + :alt: ROM Code Boot Modes + + ROM Code Boot Modes + +Page 2465 shows the BOOTMODE pins. + +.. figure:: figures/pin-mapping.png + :align: center + :alt: BOOTMODE Pin Mapping + + BOOTMODE Pin Mapping + +Page 14 of https://git.beagleboard.org/beagleplay/beagleplay/-/blob/main/BeaglePlay_sch.pdf +shows how the BOOTMODE pins are set during boot. + +.. figure:: figures/bootstrap.png + :align: center + :alt: bootstrap + + Bootstrap