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stm32_part1 More progress on first draft, admonition fixes

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Bastian de Byl
2020-02-12 23:07:44 -05:00
parent 4f3d51cb51
commit eb50ed1e5e
7 changed files with 125 additions and 26 deletions
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5
content/about.md
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@@ -24,10 +24,9 @@ you are on a mobile device, and my full public key:
`70A4 AA02 555D BD55 9189 B4E0 F32B E05E ADAA 54FC`[^2]
</center>
{{% admonition info "Public Key" true %}}
{{< admonition info "Public Key" true >}}
```
-----BEGIN PGP PUBLIC KEY BLOCK-----
mQINBFoTpoMBEADDIjRewOTvJBQF4ZxK/LS7yBL0TuU7VbZzEH3s5YKj63P/Rmvx
8/jMm0iop+uiPNo+0imIGYsdfW77bt95I9+kBm27eVf8mDMldMiS/LBCCmnuQ19u
uCq1Fd1O9JQyqxOegianl73NqtvG1UHXmnjdskDJ0N1hP0I7//g61TQkj+Qih8oI
@@ -146,7 +145,7 @@ KpNnEkXDMtMCsNkEMzM+3/BkuxLO52zYpDe5tV7Igx0=
-----END PGP PUBLIC KEY BLOCK-----
```
{{% /admonition %}}
{{< /admonition >}}
# Resume
I do not currently keep an up-to-date version of my resume. In the past, I have

4
content/post/emacs_clang_libopencm3.md
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@@ -95,13 +95,13 @@ For an STM32F0 project, the context of the `.clang_complete` file would be:
<sub>The above assumes that `libopencm3` is also places within the project
directory</sub>
{{% admonition warning Note %}}
{{< admonition warning Note >}}
There is a strange issue that is encountered with non-working completion for new
header include statements. The workaround for this includes running `M-x irony-server-kill`after new header
additions to your current working file. Irony's server is clever enough to
restart itself after a completion request is triggered via `TAB` so this is a
fairly uninvolved workaround.
{{% /admonition %}}
{{< /admonition >}}
## Example
{{< img src="/static/img/emacs-clang-libopencm3/completion.png"

16
content/post/gpg_best_practices_and_git.md
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@@ -84,37 +84,37 @@ this via:
+ **Debian/Ubuntu, RHEL:** `sudo update-ca-certificates`
{{% admonition tip "CA Path" %}}
{{< admonition tip "CA Path" >}}
On my system the full path to the CA certs is:
- `/etc/ca-certificates/extracted/cadir/sks-keyservers.net_CA.pem`
{{% /admonition %}}
{{< /admonition >}}
Two following parameters should be added to your `~/.gnupg` configuration files:
### GnuPG Versions >2.1
{{% admonition note "gpg.conf" %}}
{{< admonition note "gpg.conf" >}}
```
keyserver hkps://hkps.pool.sks-keyservers.net
```
{{% /admonition %}}
{{< /admonition >}}
{{% admonition note "dirmngr.conf" %}}
{{< admonition note "dirmngr.conf" >}}
```
hkp-cacert /etc/ca-certificates/path/to/CA.pem
```
{{% /admonition %}}
{{< /admonition >}}
### GnuPG Versions <2.1
{{% admonition note "gpg.conf" %}}
{{< admonition note "gpg.conf" >}}
```
keyserver hkps://hkps.pool.sks-keyservers.net
keyserver-options ca-cert-file=/path/to/CA/sks-keyservers.netCA.pem
```
{{% /admonition %}}
{{< /admonition >}}
## *Optional* - Ensure keys refreshed through keyserver
To ensure no keys are pulled from insecure sources, or that an attacked would

4
content/post/humble-beginnings.md
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@@ -13,11 +13,11 @@ from WordPress)
<!--more-->
# Disclaimer
{{% admonition warning "Out of Date" %}}
{{< admonition warning "Out of Date" >}}
The information in this article is **out-of-date**. I am, and have been, using my
own fork of the [hugo-even-theme](https://gitlab.com/bdebyl/hugo-theme-even) on
my [GitLab](https://gitlab.com/bdebyl) profile.
{{% /admonition %}}
{{< /admonition >}}
---

8
content/post/password_checker.md
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@@ -62,10 +62,10 @@ It may be worth mentioning, to folks less familiar with `awk`, that the
being piped into `sha1sum`. I discovered incorrect `sha1sum` outputs **without**
`FNR==1` resulting in a useless password check!
{{% admonition note Note %}}
{{< admonition note Note >}}
`IFS=` would not have fixed the above newline issue, as the problem stems
from the output of `pass "$p"` and **not** the filenames.
{{% /admonition %}}
{{< /admonition >}}
That takes care of gathering our passwords, but we'll revisit this again in the
next part.
@@ -108,10 +108,10 @@ it's weak (_i.e. "Exists in attack dictionary", "Too short", etc._) was to use
well-documented or fully-fledged application to fully determine password
strength though for my purposes it will be good enough (_I don't care to write
my own version of this, yet.._).
{{% admonition note Note %}}
{{< admonition note Note >}}
I made this part of the script **optional**, as not every user would want to
install `cracklib` on their system.
{{% /admonition %}}
{{< /admonition >}}
This addition was made in the following order:

13
content/post/stm32-part0.md
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@@ -14,17 +14,20 @@ series: turn on the lights!
<!--more-->
{{% admonition warning "Windows Users" %}}
{{< admonition warning "Windows Users" >}}
This series of write-ups assumes the reader is on a Linux operating
system. Windows users _can_ utilize the [**Windows Subsystems for
Linux**](https://docs.microsoft.com/en-us/windows/wsl/install-win10) though your
mileage may vary!
{{% /admonition %}}
{{< /admonition >}}
# Straight to the Chase
For those that want to cut to the chase and save time, here is the full source
code with friendly names to get you started:
{{< admonition note "Source Code" true >}}
```C
#include <libopencm3/stm32/gpio.h>
#include <libopencm3/stm32/rcc.h>
@@ -41,8 +44,8 @@ int main(void) {
while (1);
}
```
{{< /admonition >}}
# Getting Started with libopencm3
[libopencm3](https://github.com/libopencm3/libopencm3) is a very powerful,
@@ -114,11 +117,11 @@ Makefile's variables of things you may want to change:
# Explanation
{{% admonition info "Naming Convention" %}}
{{< admonition info "Naming Convention" >}}
As a note to the reader: below I will not refer to the GPIO port or pins using
the `#define` friendly names from above. This is purely for the sake
of clarity in hopes of avoiding confusion.
{{% /admonition %}}
{{< /admonition >}}
Although the source code is fairly simple, lets dive into it at least
_somewhat_.

101
content/post/stm32-part1.md
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@@ -1,5 +1,5 @@
---
title: "STM32 with libopencm3 - Part 1: Simple Timer"
title: "STM32F0 with libopencm3 - Part 1: Simple Timer"
date: 2020-02-12
lastmod: 2020-02-12
draft: true
@@ -8,7 +8,7 @@ categories: ["Tutorial"]
contentCopyright: false
hideHeaderAndFooter: false
---
After having reviewed [part 0](/post/stm32-part0) of this series, we can now
After having reviewed [**Part 0**](/post/stm32-part0) of this series, we can now
explore controlling GPIO with the hardware timers! Other tutorials have used the
Systick timer as a good introduction to adding a delay for blinking an
LED. However, it is my belief that this leads to confusion for beginners and
@@ -16,3 +16,100 @@ only opens the door to misunderstandings. That being said, we will be using
timers and their associated GPIO ports with Alternate Function modes.
<!--more-->
# Straight to the Chase
For those that want to cut to the chase and save time, here is the full source
code with friendly names to get you started:
{{< admonition note "Source Code" true >}}
```C
#include <libopencm3/stm32/gpio.h>
#include <libopencm3/stm32/rcc.h>
#include <libopencm3/stm32/timer.h>
#define LED_PORT GPIOC
#define LED_PIN_BLU GPIO8
#define LED_PIN_GRN GPIO9
#define TIM_PSC_DIV 48000
#define SECONDS 1
volatile unsigned int i;
int main(void) {
rcc_clock_setup_in_hsi_out_48mhz();
rcc_periph_clock_enable(RCC_GPIOC);
rcc_periph_clock_enable(RCC_TIM3);
gpio_mode_setup(LED_PORT, GPIO_MODE_AF, GPIO_PUPD_NONE, LED_PIN_BLU | LED_PIN_GRN);
gpio_set_output_options(LED_PORT, GPIO_OTYPE_PP, GPIO_OSPEED_HIGH, LED_PIN_BLU | LED_PIN_GRN);
gpio_set_af(LED_PORT, GPIO_AF0, LED_PIN_BLU | LED_PIN_GRN);
timer_set_mode(TIM3, TIM_CR1_CKD_CK_INT, TIM_CR1_CMS_CENTER_1, TIM_CR1_DIR_UP);
// The math for seconds isn't quite right here
timer_set_prescaler(TIM3, (rcc_apb1_frequency/TIM_PSC_DIV)/2*SECONDS);
timer_disable_preload(TIM3);
timer_continuous_mode(TIM3);
timer_set_period(TIM3, TIM_PSC_DIV);
timer_set_oc_mode(TIM3, TIM_OC3, TIM_OCM_PWM1);
timer_set_oc_mode(TIM3, TIM_OC4, TIM_OCM_PWM2);
int tim_oc_ids[2] = { TIM_OC3, TIM_OC4 };
for (i = 0; i < (sizeof(tim_oc_ids)/sizeof(tim_oc_ids[0])); ++i) {
timer_set_oc_value(TIM3, tim_oc_ids[i], (TIM_PSC_DIV/2));
}
timer_enable_oc_output(TIM3, TIM_OC3);
timer_enable_oc_output(TIM3, TIM_OC4);
timer_enable_counter(TIM3);
while (1) {
;
}
return 0;
}
```
{{< /admonition >}}
# Set up the GPIO
Assuming the reader is either familiar with GPIO setup for the STM32F0, or has
reviewed [**Part 0**](/post/stm32-part0) of this series we will set up the GPIO
pins tied to the LEDs (_port C, pins 8 and 9_) in the Alternate Function mode.
## Alternate Functions
The STM32 microcontroller's GPIO has a hardware feature allowing you to tie
certain port's pins to a different register as part of the output or input
control:
{{< img src="/static/img/stm32-examples/part1/stm32-af-diagram.png"
sub="GPIO Alternate Function Diagram" >}}
For accomplishing this, a few things need to happen:
1. The desired GPIO pins need to be set to `GPIO_MODE_AF` in `gpio_mode_setup()`
1. The alternate function mode number `GPIO_AFx` has to be set for the pins using `gpio_set_af()`
{{< admonition warning "Note for Different STM32Fx Microcontrollers" >}}
Review the datasheet for the specific **STM32Fx** microcontroller being
programmed, as the Alternate Function mappings may be *significantly* different!
{{< /admonition >}}
## GPIO Alternate Function Setup
For the STM32F0 we are using in this series, the Alternate Function selection
number desired is `GPIO_AF0` for use with `TIM3_CH3` (_timer 3, channel 3_) and
`TIM3_CH4` (_timer 3, channel 4_):
{{< img src="/static/img/stm32-examples/part1/stm32-af-gpiomap.png"
sub="STM32F051 Alternate Function Mapping" >}}
Ultimately, the code with `libopencm3` becomes the following for our use case:
```C
gpio_mode_setup(GPIOC, GPIO_MODE_AF, GPIO_PUPD_NONE, GPIO8 | GPIO9);
gpio_set_output_options(GPIOC, GPIO_OTYPE_PP, GPIO_OSPEED_HIGH, GPIO8 | GPIO9);
gpio_set_af(GPIOC, GPIO_AF0, GPIO8 | GPIO9);
```