2017-10-09 21:06:47 +02:00
|
|
|
README
|
|
|
|
======
|
|
|
|
|
2017-10-09 21:40:54 +02:00
|
|
|
This README file discusses the port of NuttX to the Raspberry Pi Zero.
|
|
|
|
The Raspberry Pi Zero is based on the Broadcom BCM2835 CPU. This is the
|
|
|
|
same Broadcom chip used in the Raspberry Pi Model A, B, B+, the Compute
|
|
|
|
Module.
|
|
|
|
|
|
|
|
STATUS
|
|
|
|
======
|
|
|
|
|
|
|
|
2017-10-09: This is a work in progress. The port is not complete and
|
|
|
|
will not build to completion. Missing logic includes:
|
|
|
|
|
|
|
|
- GPIO support,
|
|
|
|
- System timer initialization, and
|
|
|
|
- Serial driver.
|
|
|
|
|
2017-10-20 00:14:18 +02:00
|
|
|
2017-10-19: Much of that logic is in place but there are a few things
|
|
|
|
still missing.
|
|
|
|
|
|
|
|
- Mini-UART Baud divisor calculation,
|
2018-10-12 22:52:05 +02:00
|
|
|
- Start-up logic. My understand from what I have read on the Internet
|
2017-10-20 00:14:18 +02:00
|
|
|
is the PiZero OS starts up in hypervisor mode with the MMU and I- and
|
2018-10-12 22:52:05 +02:00
|
|
|
D-Caches enabled. This probably means that the standard, classic ARM
|
2017-10-20 00:14:18 +02:00
|
|
|
startup logic at at arch/arm/src/arm/up_head.S will need to be replaced
|
|
|
|
with some custom logic.
|
|
|
|
|
|
|
|
No testing has yet been performed.
|
|
|
|
|
2017-10-09 21:06:47 +02:00
|
|
|
Basic Setup
|
|
|
|
===========
|
|
|
|
|
|
|
|
+------------+
|
|
|
|
| |
|
|
|
|
| +--+
|
|
|
|
| USB | | <----------------------------> USB Power Source
|
|
|
|
| +--+ +------------+
|
|
|
|
| | | +--+
|
|
|
|
| +--+ | | | <---> Keyboard
|
|
|
|
| USB | | <-------->| USB +--+
|
|
|
|
| +--+ | HUB |
|
|
|
|
| | | +--+
|
|
|
|
| | | | | <---> Mouse
|
|
|
|
| | | +--+
|
|
|
|
| | +------------+
|
|
|
|
| Mini +--+
|
|
|
|
| HDMI | | <----------------------------> Monitor/TV
|
|
|
|
| +--+
|
|
|
|
| |
|
|
|
|
+------------+
|
|
|
|
|
|
|
|
You might be able to use the hub to power the Pi Zero, but I was not
|
|
|
|
able to do that; my hub would not switch on power until it was enumerated
|
|
|
|
by the host (the Raspberry Pi Zero), but then I could not power the Pi
|
|
|
|
with the hub because it was not providing power. Chicken'n'Egg.
|
2017-10-09 21:40:54 +02:00
|
|
|
|
|
|
|
NuttX Boot Sequence
|
|
|
|
===================
|
|
|
|
|
|
|
|
To be provided.
|
|
|
|
|
|
|
|
Configurations
|
|
|
|
==============
|
|
|
|
|
|
|
|
Information Common to All Configurations
|
|
|
|
----------------------------------------
|
|
|
|
Each Raspberry Pi Zero configuration is maintained in a sub-directory
|
|
|
|
and can be selected as follow:
|
|
|
|
|
|
|
|
tools/configure.sh [OPTIONS] pizero/<subdir>
|
|
|
|
|
|
|
|
Where [OPTIONS] include -l to configure for a Linux host platform and
|
|
|
|
-c means to configure for a Windows Cygwin host platform. -h will give
|
|
|
|
you the list of all options.
|
|
|
|
|
|
|
|
Before building, make sure the PATH environment variable includes the
|
|
|
|
correct path to the directory than holds your toolchain binaries.
|
|
|
|
|
|
|
|
And then build NuttX by simply typing the following. At the conclusion of
|
|
|
|
the make, the nuttx binary will reside in an ELF file called, simply, nuttx.
|
|
|
|
|
|
|
|
make
|
|
|
|
|
|
|
|
The <subdir> that is provided above as an argument to the tools/configure.sh
|
|
|
|
must be is one of the following.
|
|
|
|
|
|
|
|
NOTES:
|
|
|
|
|
|
|
|
1. These configurations use the mconf-based configuration tool. To
|
|
|
|
change any of these configurations using that tool, you should:
|
|
|
|
|
|
|
|
a. Build and install the kconfig-mconf tool. See nuttx/README.txt
|
|
|
|
see additional README.txt files in the NuttX tools repository.
|
|
|
|
|
|
|
|
b. Execute 'make menuconfig' in nuttx/ in order to start the
|
|
|
|
reconfiguration process.
|
|
|
|
|
|
|
|
Configuration Sub-directories
|
|
|
|
-----------------------------
|
|
|
|
|
|
|
|
nsh:
|
|
|
|
|
|
|
|
This simple configuration directory provide the NuttShell (NSH).
|