Hi AmForth List,
on the weekend I've run the "Arduino Hello World" recipe and found
two
issues:
a) the recipe jumps from pin 5 to pin 7 of Port B in the middle of
the
recipe, that was confusing
b) modern AmForth does not seem to include the word "ms" in the
kernel
Attached is a patch that changes to Port to use Digital-13 on the
Arduino all the time (to be consistent) and gives information
where to
find the word "ms" (or how to quickly define it).
<https://git.sr.ht/~cstrotm/AmForth/commit/a2a968b7c02aff5afd622f842aeda9a21ddcdc92.patch>
Greetings
Carsten
From a2a968b7c02aff5afd622f842aeda9a21ddcdc92 Mon Sep 17 00:00:00
2001
From: Carsten Strotmann <cars...@strotmann.de>
Date: Mon, 1 Mar 2021 13:55:20 +0100
Subject: [PATCH] Fix port number in example and add information on
word "ms"
---
.../TG/recipes/Arduino-HelloWorld.rst.txt | 52
+++++++++++--------
1 file changed, 29 insertions(+), 23 deletions(-)
diff --git
a/doc/htdocs/_sources/TG/recipes/Arduino-HelloWorld.rst.txt
b/doc/htdocs/_sources/TG/recipes/Arduino-HelloWorld.rst.txt
index 7de8045..93bb471 100644
--- a/doc/htdocs/_sources/TG/recipes/Arduino-HelloWorld.rst.txt
+++ b/doc/htdocs/_sources/TG/recipes/Arduino-HelloWorld.rst.txt
@@ -9,7 +9,7 @@ attached to the port Digital-13. For this recipe,
the amforth system
is already loaded onto the ardiuno. Instructions to do it are in
the
:ref:`User Guide`.
-To quickly test the hardware start a terminal (e.g. screen
/dev/ttyACM0 38400)
+To quickly test the hardware start a terminal (e.g. screen
/dev/ttyACM0 38400)
and enter the following commands (assuming an Arduino Uno)
.. code-block:: forth
@@ -19,12 +19,12 @@ and enter the following commands (assuming an
Arduino Uno)
> $00 $25 c!
The LED turned on until the last command is executed. The
character
-:command:`>` is the command prompt, if you see it, you can enter
-any commands. You'll never enter that character yourselves. A
+:command:`>` is the command prompt, if you see it, you can enter
+any commands. You'll never enter that character yourselves. A
command line can be up to 80 characters long.
The commands above are pretty obscure. To make them easier to
-understand we define labels for some numbers, so called
+understand we define labels for some numbers, so called
constants:
.. code-block:: forth
@@ -35,24 +35,24 @@ constants:
The arduino uses its own numbering schema for pins, but
for now we use the atmega one: digial-13 is the same as
bit 7 of port B. Port B has 8 pins and three registers to
-configure them. we need two of them: The Data Direction
-Register (DDR) and the PORT (Output) Register. The third
+configure them. we need two of them: The Data Direction
+Register (DDR) and the PORT (Output) Register. The third
register is used for reading from the port (PIN).
The above commands can now be written as
.. code-block:: forth
- > $20 DDRB c!
+ > $20 DDRB c!
> $20 PORTB c!
> $00 PORTB c!
Technically the same but easier to read.
Next we do not want to enter all commands interactively. Forth
-has the reputation of an extendible command set.
+has the reputation of an extendible command set.
-Good forth coding style means to have many small words which do
exactly
+Good forth coding style means to have many small words which do
exactly
one thing. Most forth commands are built with only a handful
other commands.
The first command in this example sets up the Data Direction
Register DDR
@@ -68,7 +68,7 @@ The same in Forth is:
.. code-block:: forth
- > : led-init $80 DDRB c! ;
+ > : led-init $20 DDRB c! ;
ok
>
@@ -81,17 +81,17 @@ With this command line the interpreter learns
a new command:
ok
>
-It writes the number 128 (hex 80) to the register DDRB (hex 24)
-as defined above. This makes the 7th bit of PORTB an Output pin.
+It writes the number 32 (hex 20) to the register DDRB (hex 24)
+as defined above. This makes the 5th bit of PORTB an Output pin.
Calling our newly defined word does not change anything
visible. But with the next word, the LED will turn on:
.. code-block:: forth
- : led-on $80 PORTB c! ;
+ : led-on $20 PORTB c! ;
-Here the 7th bit will be set to 1, and that makes the led to be
connected
+Here the 5th bit will be set to 1, and that makes the led to be
connected
to VCC (5V) and it will turn on (the LED is connected to ground
already).
If the led-on command does not turn on the LED just call the
@@ -123,9 +123,15 @@ Our next word will simplify this and gives
the real blink experience:
: led-blink led-on 500 ms led-off 500 ms ;
-Calling this command will turn on the led, waits for half a
second, turn it
-off again and waits another half a second before returning to the
command
-prompt.
+Calling this command will turn on the led, waits for half a
second,
+turn it off again and waits another half a second before
returning to
+the command prompt. If the word `ms` is not found, it can be
loaded
+from `<AmForth>/common/lib/forth2012/facility/ms.frt` or defined
+assembler
+
+.. code-block:: forth
+
+ : ms 0 ?do 1ms loop ;
With this command you can blink the led a few times
@@ -148,11 +154,11 @@ To make it blink "forever", we define
another command word:
led-blink
key?
until
- key drop
+ key drop
;
-Since this is our first command which needs more than 1 line, the
-interpreter acts more complex. It changes the command prompt
until
+Since this is our first command which needs more than 1 line, the
+interpreter acts more complex. It changes the command prompt
until
the end of the command definition is reached (the command ``;``)
The ouput in the terminal window looks like
@@ -167,7 +173,7 @@ The ouput in the terminal window looks like
okkey drop
ok;
ok
- >
+ >
This word first prints some text ("press any key to stop") and
starts a loop.
This loop lets the led blink once and checks for a keystroke. If
no key
@@ -185,7 +191,7 @@ Where to go next
................
This example is very basic. Next steps may involve library code
-like :ref:`Digital Ports`. Related to it are the :ref:`Upload`
for
+like :ref:`Digital Ports`. Related to it are the :ref:`Upload`
for
files with forth code.
-More Arduino related stuff is in :ref:`Arduino Analog`.
+More Arduino related stuff is in :ref:`Arduino Analog`.
--
2.30.1
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