Create README.md

Corrected typos in README

README.md

@@ -1,3 +1,9 @@
+**This library is very old and unmaintained.**
+
+There may be some good bits worth salvaging, but for new projects I recommend the [avr-c-boilerplate](https://github.com/MightyPork/avr-c-boilerplate) as a base instead. Copy and port good modules from this library if you like.
+
+---
+
 # "porklib", MightyPork's Arduino Library
 
 This library aims to make development for AVR in C easy and fun.
@@ -12,12 +18,12 @@ Pull requests to add new modules are welcome, please go ahead!
 
 ## Makefile
 
-You can use the provided Makefile to boild your project with this library.
+You can use the provided Makefile to build your project with this library.
 
 A project typically consists of one `main.c` file, and some `*_config.c` files where the
 library headers request it (those define eg. IO pin mapping).
 
-Adjust the Makefile to yoru needs!
+Adjust the Makefile to your needs!
 
 ## License
 

examples/sipo_pwm_74xx4094_595/sipo_pwm_config.h

@@ -1,10 +1,17 @@
 /* Config for SIPO PWM */
 
-// PWM pin aliases
+// --- PWM pin aliases ---
+
+// Store signal
 #define SPWM_STR  D2
+// Shift/clock signal
 #define SPWM_CLK  D3
+// Data signal
 #define SPWM_DATA D4
 
+
+// --- Other settings ---
+
 // Number of PWM levels (color depth)
 #define SPWM_COLOR_DEPTH 256
 

lib/sipo_pwm.h

@@ -2,23 +2,28 @@
 
 // --- SIPO PWM Module ---
 //
-// SIPO = Serial IN, Parallel OUT
+// SIPO = shift register with paralel output.
 //
 // This module lets you use SIPO outputs as a "software PWM".
 //
-// Tested on 74HC4094,
+// Tested to work on 74hc4094 and 74hc595
-// should also work on 74HC595 (may need some small changes)
 
 #include <stdint.h>
 
 // Your file with configs
 #include "sipo_pwm_config.h"
 /*
-	// PWM pin aliases
+	// --- PWM pin aliases ---
+	
+	// Store signal
 	#define SPWM_STR  D2
+	// Shift/clock signal
 	#define SPWM_CLK  D3
+	// Data signal
 	#define SPWM_DATA D4
 	
+	// --- Other settings ---
+	
 	// Number of PWM levels (color depth)
 	#define SPWM_COLOR_DEPTH 256
 	
@@ -38,7 +43,7 @@ extern uint8_t spwm_levels[SPWM_CHANNELS];
 void spwm_init();
 
 
-/** Display PWM channels.
+/** Perform one PWM cycle.
- * This could be called in a Timer ISR.
+ * This should be called in a Timer ISR or a loop.
  */
 void spwm_send();