diff --git a/lcd_hept/Makefile b/lcd_hept/Makefile
index 7d5678e..b5b61fd 100644
--- a/lcd_hept/Makefile
+++ b/lcd_hept/Makefile
@@ -2,7 +2,7 @@ CC = avr-gcc
 OBJCOPY = avr-objcopy
 AVRDUDE = avrdude
 CFLAGS = -Os -DF_CPU=16000000UL -mmcu=atmega328p 
-SERIAL = /dev/cu.usbmodem143401
+SERIAL = /dev/cu.usbmodem141401
 ADDR = $(shell heptc -where)/c
 TARGET = prog
 LIB = arduinolib
diff --git a/lcd_hept/arduinolib.c b/lcd_hept/arduinolib.c
index 4757f5d..357a6eb 100644
--- a/lcd_hept/arduinolib.c
+++ b/lcd_hept/arduinolib.c
@@ -54,12 +54,6 @@ void Arduinolib__lcd_init_step(Arduinolib__lcd_init_out *out){
     Arduinolib__lcd_cmd_step(LCD_DISPLAY_ON, o9);
     _delay_us(80); //more than 39us
 
-
-    // if we use this code the msg is printed ///
-    /*uint8_t msg[] = "Arduino";
-    Arduinolib__lcd_string_out *o;
-    Arduinolib__lcd_string_step(msg, o);*/
-
 }
 
 /* send an 8bit information to the LCD register in order to be written */
@@ -104,9 +98,9 @@ void Arduinolib__lcd_cmd_step(uint8_t cmd, Arduinolib__lcd_cmd_out *out){
     LCD_RS_PORT &= ~(1 << LCD_RS_PIN); //low
     LCD_E_PORT &= ~(1 << LCD_E_PIN); //low
     Arduinolib__lcd_write_out *o1;
-    Arduinolib__lcd_write_step(cmd, o1); // upper 4 bits
+    Arduinolib__lcd_write_step(cmd, o1); // write upper 4 bits
     Arduinolib__lcd_write_out *o2;
-    Arduinolib__lcd_write_step(cmd << 4, o2); // lower 4 bits
+    Arduinolib__lcd_write_step(cmd << 4, o2); // write lower 4 bits
 }
 
 /* send an 8bit data character to the LCD register */
@@ -115,9 +109,9 @@ void Arduinolib__lcd_char_step(uint8_t char_data, Arduinolib__lcd_char_out *out)
     LCD_RS_PORT |= (1 << LCD_RS_PIN); //high
     LCD_E_PORT &= ~(1 << LCD_E_PIN); //low
     Arduinolib__lcd_write_out *o1;
-    Arduinolib__lcd_write_step(char_data, o1); // upper 4 bits
+    Arduinolib__lcd_write_step(char_data, o1); //write upper 4 bits
     Arduinolib__lcd_write_out *o2;
-    Arduinolib__lcd_write_step(char_data << 4, o2); // lower 4 bits
+    Arduinolib__lcd_write_step(char_data << 4, o2); //write lower 4 bits
 }
 
 /* give a string to display to the LCD*/ 
@@ -126,10 +120,10 @@ void Arduinolib__lcd_string_step(uint8_t lstring[], int line, Arduinolib__lcd_st
     Arduinolib__lcd_cmd_out *o2;
     if (line == 1) { 
         Arduinolib__lcd_cmd_step(LCD_CURSOR_SET | LCD_START_LINE2, o1);
-        _delay_us(80); //more than 
+        _delay_us(80); //more than 39us
     } else {
         Arduinolib__lcd_cmd_step(LCD_CURSOR_SET | LCD_START_LINE1, o2);
-        _delay_us(80);
+        _delay_us(80); //more than 39us
     }
     volatile int i = 0;
     for (i = 0; lstring[i] != 0 ; i++) {
@@ -141,9 +135,61 @@ void Arduinolib__lcd_string_step(uint8_t lstring[], int line, Arduinolib__lcd_st
 
 /* gice a number to display to the LCD */
 void Arduinolib__lcd_int_step(uint8_t numb, int line, Arduinolib__lcd_int_out *out){
-    char lstring[80];
+    char lstring[80]; //buffer
     itoa(numb, lstring, 10);
     Arduinolib__lcd_string_out *o;
     Arduinolib__lcd_string_step(lstring, line, o);
 }
 
+/* a general read pin function. it is assuming the user uses distinct pins to read/write */
+void Arduinolib__dread_step(int p, Arduinolib__dread_out *out){
+    if (8 <= p && p <= 13){
+        int pin = p - 8;
+        DDRB &= ~(1 << pin);
+        if ((PINB & (1 << pin)) == (1 << pin) ) {
+            out -> v = 1; //pin high so it is pressed
+        }
+        else {
+            out -> v = 0; //pin low so it is not pressed
+        }
+    }
+    else if ( 0 <= p && p <= 7){
+        DDRD &= ~(1 << p);
+        if ((PIND & (1 << p)) == (1 << p) ) {
+            out -> v = 1; //pin high so it is pressed
+        } else {
+            out -> v = 0; //pin low so it is not pressed
+        }
+    }
+    else { //by default to pin 13 of arduino
+        DDRB &= ~(1 << 5);
+        if ((PINB & (1 << 5)) == (1 << 5) ) {
+            out -> v = 1; //pin high so it is pressed
+        }
+        else {
+            out -> v = 0; //pin low so it is not pressed
+        }
+    }
+    return;
+}
+
+void Arduinolib__dwrite_step(int p, int v, Arduinolib__dwrite_out *out){
+
+    if (8 <= p && p <= 13){
+        int pin = p - 8;
+        DDRB |= (1 << pin);
+        PORTB |= (1 << pin);
+        if (v == 0) PORTB &= ~(1 << pin);
+    }
+    else if ( 0 <= p && p <= 7){
+        DDRD |= (1 << p);
+        PORTD |= (1 << p);
+        if (v == 0) PORTD &= ~(1 << p);
+    }
+    else { //by default
+        DDRB |= (1 << 5);
+        PORTB |= (1 << 5);
+        if (v == 0) PORTB &= ~(1 << 5);
+    }
+    return;
+}
diff --git a/lcd_hept/arduinolib.epi b/lcd_hept/arduinolib.epi
index 067bb6e..8f86a7f 100644
--- a/lcd_hept/arduinolib.epi
+++ b/lcd_hept/arduinolib.epi
@@ -6,3 +6,5 @@ fun lcd_cmd(cmd:uint8_t) returns ()
 fun lcd_char(char_data:uint8_t) returns ()
 fun lcd_string (lstring:string; line:int) returns ()
 fun lcd_int (numb:uint8_t; line:int) returns ()
+fun dread(buttonpin: int) returns (v : int)
+fun dwrite(p:int; v:int) returns ()
\ No newline at end of file
diff --git a/lcd_hept/arduinolib_types.h b/lcd_hept/arduinolib_types.h
index 7180505..8f2c4fa 100644
--- a/lcd_hept/arduinolib_types.h
+++ b/lcd_hept/arduinolib_types.h
@@ -1,16 +1,6 @@
 #ifndef ARDUINOLIB_H
 #define ARDUINOLIB_H
 
-//typedef struct string {
-//    const char *msg
-//} Arduinolib__string_out;
-
-typedef struct byte_out {
-  uint8_t value ;
-} byte_out ;
-
-typedef byte_out Arduinolib__bitOr_out ;
-
 typedef struct Arduinolib__lcd_init {
 } Arduinolib__lcd_init_out;
 
@@ -29,6 +19,13 @@ typedef struct Arduinolib__lcd_string {
 typedef struct Arduinolib__lcd_int {
 } Arduinolib__lcd_int_out;
 
+typedef struct Arduinolib__dread {
+  int v;
+} Arduinolib__dread_out;
+
+typedef struct Arduinolib__dwrite {
+} Arduinolib__dwrite_out;
+
 void Arduinolib__lcd_init_step(Arduinolib__lcd_init_out *o);
 
 void Arduinolib__lcd_write_step(uint8_t info, Arduinolib__lcd_write_out *o);
@@ -41,4 +38,8 @@ void Arduinolib__lcd_string_step(uint8_t lstring[], int line, Arduinolib__lcd_st
 
 void Arduinolib__lcd_int_step(uint8_t numb, int line, Arduinolib__lcd_int_out *o);
 
+void Arduinolib__dread_step(int p, Arduinolib__dread_out *out);
+
+void Arduinolib__dwrite_step(int p, int v, Arduinolib__dwrite_out *out);
+
 #endif
\ No newline at end of file
diff --git a/lcd_hept/prog.ept b/lcd_hept/prog.ept
index be1444e..18a6d9e 100644
--- a/lcd_hept/prog.ept
+++ b/lcd_hept/prog.ept
@@ -23,14 +23,18 @@ let
     () = lcd_int(count/period, line);
 tel
 
-node main() returns ()
-var start : bool;
+node button (bpin, ledpin : int) returns ()
+var value : int;
+    i : int;
 let
-  start = true fby false;
-  () = lcd_init() when start;
+  i = 0 fby (i+1);
+  value = dread(bpin);
+  () = dwrite((ledpin, value));
+tel
 
-  () = lcd_blink_msg ((2, 1, "hello world!", 0) when not start);
-  () = lcd_counter ((1, 1) when not start);
 
+node main() returns ()
+let 
+    () = button (8, 13);
 tel
 
diff --git a/led_button/Makefile b/led_button/Makefile
new file mode 100644
index 0000000..b5b61fd
--- /dev/null
+++ b/led_button/Makefile
@@ -0,0 +1,42 @@
+CC = avr-gcc
+OBJCOPY = avr-objcopy
+AVRDUDE = avrdude
+CFLAGS = -Os -DF_CPU=16000000UL -mmcu=atmega328p 
+SERIAL = /dev/cu.usbmodem141401
+ADDR = $(shell heptc -where)/c
+TARGET = prog
+LIB = arduinolib
+MAIN = main
+
+
+.PHONY: all clean flash
+
+all: $(TARGET).hex
+
+flash: $(TARGET).hex
+	$(AVRDUDE) -F -V -c arduino -p ATMEGA328P -P $(SERIAL) -b 115200 \
+	    -U flash:w:$<
+
+
+$(TARGET).hex: $(TARGET)
+	$(OBJCOPY) -O ihex -R .eeprom $< $@
+
+
+$(TARGET): $(TARGET).o
+	$(CC) $(CFLAGS) -o $@ *.o
+
+$(TARGET).o : $(TARGET).c
+	$(CC) -g $(CFLAGS) -c -I $(ADDR) -I . $(LIB).c $(TARGET)_c/*.c $(MAIN).c
+
+
+$(TARGET).c:
+	heptc $(LIB).epi
+	heptc -target c $(TARGET).ept
+
+
+clean:
+	rm -f $(TARGET) $(TARGET).hex $(TARGET).o $(TARGET).log $(TARGET).mls
+	rm -f *.o *.epci
+	rm -r $(TARGET)_c
+
+
diff --git a/led_button/arduinolib.c b/led_button/arduinolib.c
new file mode 100644
index 0000000..fad2a12
--- /dev/null
+++ b/led_button/arduinolib.c
@@ -0,0 +1,55 @@
+#include <avr/io.h>
+#include <util/delay.h>
+#include "arduinolib.h"
+
+void Arduinolib__dwrite_step(int p, int v, Arduinolib__dwrite_out *out){
+
+    if (8 <= p && p <= 13){
+        int pin = p - 8;
+        DDRB |= (1 << pin);
+        PORTB |= (1 << pin);
+        if (v == 0) PORTB &= ~(1 << pin);
+    }
+    else if ( 0 <= p && p <= 7){
+        DDRD |= (1 << p);
+        PORTD |= (1 << p);
+        if (v == 0) PORTD &= ~(1 << p);
+    }
+    else { //by default
+        DDRB |= (1 << 5);
+        PORTB |= (1 << 5);
+        if (v == 0) PORTB &= ~(1 << 5);
+    }
+    return;
+}
+
+void Arduinolib__dread_step(int p, Arduinolib__dread_out *out){
+    if (8 <= p && p <= 13){
+        int pin = p - 8;
+        DDRB &= ~(1 << pin);
+        if ((PINB & (1 << pin)) == (1 << pin) ) {
+            out -> v = 1; //pin high so it is pressed
+        }
+        else {
+            out -> v = 0; //pin low so it is not pressed
+        }
+    }
+    else if ( 0 <= p && p <= 7){
+        DDRD &= ~(1 << p);
+        if ((PIND & (1 << p)) == (1 << p) ) {
+            out -> v = 1; //pin high so it is pressed
+        } else {
+            out -> v = 0; //pin low so it is not pressed
+        }
+    }
+    else { //by default to pin 13 of arduino
+        DDRB &= ~(1 << 5);
+        if ((PINB & (1 << 5)) == (1 << 5) ) {
+            out -> v = 1; //pin high so it is pressed
+        }
+        else {
+            out -> v = 0; //pin low so it is not pressed
+        }
+    }
+    return;
+}
diff --git a/led_button/arduinolib.epi b/led_button/arduinolib.epi
new file mode 100644
index 0000000..515e324
--- /dev/null
+++ b/led_button/arduinolib.epi
@@ -0,0 +1,3 @@
+fun dwrite(p:int; v:int) returns ()
+fun dread(p:int) returns (v: int)
+
diff --git a/led_button/arduinolib.h b/led_button/arduinolib.h
new file mode 100644
index 0000000..74ec448
--- /dev/null
+++ b/led_button/arduinolib.h
@@ -0,0 +1 @@
+#include "arduinolib_types.h"
diff --git a/led_button/arduinolib_types.h b/led_button/arduinolib_types.h
new file mode 100644
index 0000000..0d89945
--- /dev/null
+++ b/led_button/arduinolib_types.h
@@ -0,0 +1,15 @@
+#ifndef ARDUINOLIB_H
+#define ARDUINOLIB_H
+
+typedef struct Arduinolib__dwrite {
+} Arduinolib__dwrite_out;
+
+typedef struct Arduinolib__dread {
+    int v;
+} Arduinolib__dread_out;
+
+void Arduinolib__dwrite_step(int p, int v,Arduinolib__dwrite_out *o);
+
+void Arduinolib__dread_step(int p, Arduinolib__dread_out *o);
+
+#endif
diff --git a/led_button/main.c b/led_button/main.c
new file mode 100644
index 0000000..5ac2302
--- /dev/null
+++ b/led_button/main.c
@@ -0,0 +1,15 @@
+#include <avr/io.h>
+#include <util/delay.h>
+#include "main.h"
+
+int main (void)
+{
+ Prog__main_mem mem;
+ Prog__main_reset(&mem);
+ while(1){
+     Prog__main_out _res;
+     Prog__main_step(&_res, &mem);
+    _delay_ms(1);
+}
+return 0;
+}
\ No newline at end of file
diff --git a/led_button/main.h b/led_button/main.h
new file mode 100644
index 0000000..7269ffa
--- /dev/null
+++ b/led_button/main.h
@@ -0,0 +1,4 @@
+#ifndef MAIN_H
+#define MAIN_H
+#include "prog_c/prog.h"
+#endif
diff --git a/led_button/prog.ept b/led_button/prog.ept
new file mode 100644
index 0000000..ffd79c1
--- /dev/null
+++ b/led_button/prog.ept
@@ -0,0 +1,16 @@
+open Arduinolib
+
+node button (bpin, ledpin : int) returns ()
+var value : int;
+    i : int;
+let
+  i = 0 fby (i+1);
+  value = dread(bpin);
+  () = dwrite((ledpin, value));
+tel
+
+node main() returns ()
+let
+  () = button(8, 13);
+tel
+
diff --git a/parallel_led/Makefile b/parallel_led/Makefile
index 7d5678e..b5b61fd 100644
--- a/parallel_led/Makefile
+++ b/parallel_led/Makefile
@@ -2,7 +2,7 @@ CC = avr-gcc
 OBJCOPY = avr-objcopy
 AVRDUDE = avrdude
 CFLAGS = -Os -DF_CPU=16000000UL -mmcu=atmega328p 
-SERIAL = /dev/cu.usbmodem143401
+SERIAL = /dev/cu.usbmodem141401
 ADDR = $(shell heptc -where)/c
 TARGET = prog
 LIB = arduinolib