diff --git a/main.c b/main.c
index 07ee024..0e54b4d 100644
--- a/main.c
+++ b/main.c
@@ -33,14 +33,16 @@
 const char help_00[] PROGMEM = "commands:\n";
 const char help_01[] PROGMEM = "\thelp                  display this help\n";
 const char help_02[] PROGMEM = "\tled on|off|toggle     change LED state\n";
-const char help_03[] PROGMEM = "\tread [B-D][0-7]       read value from pin\n";
-const char help_04[] PROGMEM = "\twrite [B-D][0-7] 0|1  write value on pin\n";
+const char help_03[] PROGMEM = "\tread [b-dB-D][0-7]       read value from pin\n";
+const char help_04[] PROGMEM = "\twrite [b-dB-D][0-7] 0|1  write value on pin\n";
+const char help_05[] PROGMEM = "\t[b-dB-D][0-7][0|1]    read/write value from/on pin\n";
 PGM_P const help_table[] PROGMEM = {
     help_00,
     help_01,
     help_02,
     help_03,
-    help_04
+    help_04,
+    help_05
 };
 
 /* global variables */
@@ -68,6 +70,87 @@ void led_toggle(void)
 	LED_PIN |= (1<<LED_IO);
 }
 
+/* write value on pin from port
+ * all parameters are ASCII encoded
+ * return -1 if failed, else value
+ */
+int8_t write_pin(char port, char pin, char value) {
+	if (((port>='b' && port<='d') || (port>='B' && port<='D')) && pin>='0' && pin<='7' && value>='0' && value<='1') {
+		uint8_t ppin = pin-'0';
+		volatile uint8_t * pport = NULL;
+		volatile uint8_t * ddr = NULL;
+		switch (port) {
+			case 'b':
+			case 'B':
+				pport = &PORTB;
+				ddr = &DDRB;
+				break;
+			case 'c':
+			case 'C':
+				pport = &PORTC;
+				ddr = &DDRC;
+				break;
+			case 'd':
+			case 'D':
+				pport = &PORTD;
+				ddr = &DDRD;
+				break;
+			default:
+				return -1;
+				break;
+		}
+		*ddr |= (1<<ppin); // set as output
+		/* write value */
+		if ('0'==value) {
+			*pport &= ~(1<<ppin);
+			return 0;
+		} else if ('1'==value) {
+			*pport |= (1<<ppin);
+			return 1;
+		} else {
+			return -1;
+		}
+	} else {
+		return -1;
+	}
+}
+
+/* read value from pin from port
+ * all parameters are ASCII encoded
+ * return -1 if failed, else value
+ */
+int8_t read_pin(char port, char pin) {
+	if (((port>='b' && port<='d') || (port>='B' && port<='D')) && pin>='0' && pin<='7') {
+		uint8_t ppin = pin-'0';
+		volatile uint8_t * pport = NULL;
+		volatile uint8_t * ddr = NULL;
+		switch (port) {
+			case 'b':
+			case 'B':
+				pport = &PINB;
+				ddr = &DDRB;
+				break;
+			case 'c':
+			case 'C':
+				pport = &PINC;
+				ddr = &DDRC;
+				break;
+			case 'd':
+			case 'D':
+				pport = &PIND;
+				ddr = &DDRD;
+				break;
+			default:
+				return -1;
+				break;
+		}
+		*ddr &= ~(1<<ppin); // set as input
+		return ((*pport>>ppin)&0x1);
+	} else {
+		return -1;
+	}
+}
+
 void help(void)
 {
 	char* str;
@@ -145,69 +228,43 @@ void command_action()
 	} else if (0==strcmp(word,"read")) {
 		/* expecting pin */
 		word = strtok(NULL,delimiter);
-		if (!word) {
+		if (!word || strlen(word)!=2) {
 			goto error;
 		}
-		if (2==strlen(word) && word[0]>='B' && word[0]<='D' && word[1]>='0' && word[1]<='7') {
-			volatile uint8_t * pin = NULL;
-			volatile uint8_t * ddr = NULL;
-			switch (word[0]) {
-				case 'B':
-					pin = &PINB;
-					ddr = &DDRB;
-					break;
-				case 'C':
-					pin = &PINC;
-					ddr = &DDRC;
-					break;
-				case 'D':
-					pin = &PIND;
-					ddr = &DDRD;
-					break;
-			}
-			*ddr &= ~(1<<(word[1]-'0')); // set as input
-			printf("%s: %u\n", word, (*pin>>(word[1]-'0'))&0x1); // print value
+		int8_t value = read_pin(word[0],word[1]);
+		if (value>=0) {
+			printf("%s: %d\n", word, value);
 		} else {
 			goto error;
 		}
 	} else if (0==strcmp(word,"write")) {
 		/* expecting pin */
-		word = strtok(NULL,delimiter);
-		if (!word) {
+		char * pin = strtok(NULL,delimiter);
+		if (!pin || strlen(pin)!=2) {
 			goto error;
 		}
-		if (2==strlen(word) && word[0]>='B' && word[0]<='D' && word[1]>='0' && word[1]<='7') {
-			uint8_t pin = word[1]-'0';
-			volatile uint8_t * port = NULL;
-			volatile uint8_t * ddr = NULL;
-			switch (word[0]) {
-				case 'B':
-					port = &PORTB;
-					ddr = &DDRB;
-					break;
-				case 'C':
-					port = &PORTC;
-					ddr = &DDRC;
-					break;
-				case 'D':
-					port = &PORTD;
-					ddr = &DDRD;
-					break;
-			}
-			*ddr |= (1<<pin); // set as output
-			/* expecting value */
-			word = strtok(NULL,delimiter);
-			if (!word || strlen(word)!=1) {
-				goto error;
-			}
-			/* write value */
-			if ('0'==word[0]) {
-				*port &= ~(1<<pin);
-			} else if ('1'==word[0]) {
-				*port |= (1<<pin);
-			} else {
-				goto error;
-			}
+		/* expecting value */
+		char* value = strtok(NULL,delimiter);
+		if (!value || strlen(value)!=1) {
+			goto error;
+		}		
+		int8_t rc = write_pin(pin[0],pin[1],value[0]);
+		if (rc>=0) {
+			printf("%s: %s\n", pin, value);
+		} else {
+			goto error;
+		}
+	} else if (2==strlen(word)) { // read value
+		int8_t value = read_pin(word[0],word[1]);
+		if (value>=0) {
+			printf("%s: %d\n", word, value);
+		} else {
+			goto error;
+		}
+	} else if (3==strlen(word)) { // write value
+		int8_t value = write_pin(word[0],word[1],word[2]);
+		if (value>=0) {
+			printf("%c%c: %d\n", word[0],word[1],value);
 		} else {
 			goto error;
 		}