diff --git a/include/arch/arduino-nano/driver/gpio.h b/include/arch/arduino-nano/driver/gpio.h
index 47cb7dcfcd2b5bb07ca81a5e70e75463a7a8edaa..4fc9c639ce7930ef931cb739cad34304222619ca 100644
--- a/include/arch/arduino-nano/driver/gpio.h
+++ b/include/arch/arduino-nano/driver/gpio.h
@@ -57,13 +57,13 @@ class GPIO {
 			return _BV(pin % 8);
 		}
 #pragma GCC diagnostic ignored "-Wunused-parameter"
-		inline void led_on(unsigned char id) {
+		inline void led_on(unsigned char id = 0) {
 			PORTB |= _BV(PB5);
 		}
-		inline void led_off(unsigned char id) {
+		inline void led_off(unsigned char id = 0) {
 			PORTB &= ~_BV(PB5);
 		}
-		inline void led_toggle(unsigned char id) {
+		inline void led_toggle(unsigned char id = 0) {
 			PINB = _BV(PB5);
 		}
 		inline void input(unsigned char const pin) {
diff --git a/include/arch/atmega2560/driver/gpio.h b/include/arch/atmega2560/driver/gpio.h
index b163ea08e5923c9db068070231a1e39f9a5a93b9..fa400a16dea4d537994de86b43e5e2a861cd4cdb 100644
--- a/include/arch/atmega2560/driver/gpio.h
+++ b/include/arch/atmega2560/driver/gpio.h
@@ -123,13 +123,13 @@ class GPIO {
 			return _BV(pin % 8);
 		}
 #pragma GCC diagnostic ignored "-Wunused-parameter"
-		inline void led_on(unsigned char id) {
+		inline void led_on(unsigned char id = 0) {
 			PORTB |= _BV(PB7);
 		}
-		inline void led_off(unsigned char id) {
+		inline void led_off(unsigned char id = 0) {
 			PORTB &= ~_BV(PB7);
 		}
-		inline void led_toggle(unsigned char id) {
+		inline void led_toggle(unsigned char id = 0) {
 			PINB = _BV(PB7);
 		}
 		inline void input(unsigned char const pin) {
diff --git a/include/arch/blinkenrocket/driver/gpio.h b/include/arch/blinkenrocket/driver/gpio.h
index 0d76521271140f01d01c4dfb70357298306d0675..af2648d5128e50cfb5c1e317756e16a921293655 100644
--- a/include/arch/blinkenrocket/driver/gpio.h
+++ b/include/arch/blinkenrocket/driver/gpio.h
@@ -51,13 +51,13 @@ class GPIO {
 			PORTD = 0x7f;
 			DDRD = 0xff;
 		}
-		inline void led_on(unsigned char id) {
+		inline void led_on(unsigned char id = 0) {
 			PORTB |= _BV(id);
 		}
-		inline void led_off(unsigned char id) {
+		inline void led_off(unsigned char id = 0) {
 			PORTB &= ~_BV(id);
 		}
-		inline void led_toggle(unsigned char id) {
+		inline void led_toggle(unsigned char id = 0) {
 			PORTB ^= _BV(id);
 		}
 		inline void input(unsigned char const pin) {
diff --git a/include/arch/esp8266/driver/gpio.h b/include/arch/esp8266/driver/gpio.h
index b609f76a8aa5f26e0b24fa9714c7a25c186fef8c..29e79506ca7e5fcedab0544e43827e8adcbeeb81 100644
--- a/include/arch/esp8266/driver/gpio.h
+++ b/include/arch/esp8266/driver/gpio.h
@@ -20,9 +20,9 @@ class GPIO {
 		};
 
 		void setup();
-		void led_on(unsigned char id);
-		void led_off(unsigned char id);
-		void led_toggle(unsigned char id);
+		void led_on(unsigned char id = 0);
+		void led_off(unsigned char id = 0);
+		void led_toggle(unsigned char id = 0);
 		void input(unsigned char const pin);
 		void input(unsigned char const pin, bool pullup);
 		void output(unsigned char const pin);
diff --git a/include/arch/lm4f120h5qr-stellaris/driver/gpio.h b/include/arch/lm4f120h5qr-stellaris/driver/gpio.h
index f71164e6b57368d46954ce0a950a09c12e731064..3c99eb9b6fb23d9fd1ead545868741e224099a82 100644
--- a/include/arch/lm4f120h5qr-stellaris/driver/gpio.h
+++ b/include/arch/lm4f120h5qr-stellaris/driver/gpio.h
@@ -30,13 +30,13 @@ class GPIO {
 		inline void setup() {
 			mp_gpio_setup();
 		}
-		inline void led_on(unsigned char id) {
+		inline void led_on(unsigned char id = 0) {
 			mp_gpio_write(pf_1 + id, 1);
 		}
-		inline void led_off(unsigned char id) {
+		inline void led_off(unsigned char id = 0) {
 			mp_gpio_write(pf_1 + id, 0);
 		}
-		inline void led_toggle(unsigned char id) {
+		inline void led_toggle(unsigned char id = 0) {
 			mp_gpio_write(pf_1 + id, !mp_gpio_read(pf_1 + id));
 		}
 		inline void input(unsigned char const pin) {
diff --git a/include/arch/lora32u4ii/driver/gpio.h b/include/arch/lora32u4ii/driver/gpio.h
index 8bbaa4073ee936d7d27b1a706ea88aca2d05fa50..7c03f3d6f744c33b09318222750e8b46e5312926 100644
--- a/include/arch/lora32u4ii/driver/gpio.h
+++ b/include/arch/lora32u4ii/driver/gpio.h
@@ -62,13 +62,13 @@ class GPIO {
 			return _BV(pin % 8);
 		}
 #pragma GCC diagnostic ignored "-Wunused-parameter"
-		inline void led_on(unsigned char id) {
+		inline void led_on(unsigned char id = 0) {
 			PORTC |= _BV(PC7);
 		}
-		inline void led_off(unsigned char id) {
+		inline void led_off(unsigned char id = 0) {
 			PORTC &= ~_BV(PC7);
 		}
-		inline void led_toggle(unsigned char id) {
+		inline void led_toggle(unsigned char id = 0) {
 			PINC = _BV(PC7);
 		}
 		inline void input(unsigned char const pin) {
diff --git a/include/arch/msp430fr5969lp/driver/gpio.h b/include/arch/msp430fr5969lp/driver/gpio.h
index 0b8058b3ebe4fdb7aa37e7b4ff5f01967a9cc6aa..7f2a3f78b9923c411f8c194f2b013e0376b0d87a 100644
--- a/include/arch/msp430fr5969lp/driver/gpio.h
+++ b/include/arch/msp430fr5969lp/driver/gpio.h
@@ -47,21 +47,21 @@ class GPIO {
 			P4REN = 0xff & ~BIT6; // red LED
 			PJREN = BIT6 | BIT7; // HFXT (not populated)
 		}
-		inline void led_on(unsigned char id) {
+		inline void led_on(unsigned char id = 0) {
 			if (id == 0) {
 				P1OUT |= BIT0;
 			} else {
 				P4OUT |= BIT6;
 			}
 		}
-		inline void led_off(unsigned char id) {
+		inline void led_off(unsigned char id = 0) {
 			if (id == 0) {
 				P1OUT &= ~BIT0;
 			} else {
 				P4OUT &= ~BIT6;
 			}
 		}
-		inline void led_toggle(unsigned char id) {
+		inline void led_toggle(unsigned char id = 0) {
 			if (id == 0) {
 				P1OUT ^= BIT0;
 			} else {
diff --git a/include/arch/msp430fr5994lp/driver/gpio.h b/include/arch/msp430fr5994lp/driver/gpio.h
index c3f1abf03e61fbd1c04213ebf87858ff15f65aa7..d8048c0463724476bcde7a7c3bac5db62f9f69f1 100644
--- a/include/arch/msp430fr5994lp/driver/gpio.h
+++ b/include/arch/msp430fr5994lp/driver/gpio.h
@@ -63,21 +63,21 @@ class GPIO {
 			P8REN = 0xff;
 			PJREN = BIT6 | BIT7; // HFXT (not populated)
 		}
-		inline void led_on(unsigned char id) {
+		inline void led_on(unsigned char id = 0) {
 			if (id == 0) {
 				P1OUT |= BIT0;
 			} else {
 				P1OUT |= BIT1;
 			}
 		}
-		inline void led_off(unsigned char id) {
+		inline void led_off(unsigned char id = 0) {
 			if (id == 0) {
 				P1OUT &= ~BIT0;
 			} else {
 				P1OUT &= ~BIT1;
 			}
 		}
-		inline void led_toggle(unsigned char id) {
+		inline void led_toggle(unsigned char id = 0) {
 			if (id == 0) {
 				P1OUT ^= BIT0;
 			} else {
diff --git a/include/arch/posix/driver/gpio.h b/include/arch/posix/driver/gpio.h
index c630b469682ba9e4f8435ab30f09451af114fd1c..b1a7706fea55e873a8fae461fd8e6d951a526dc8 100644
--- a/include/arch/posix/driver/gpio.h
+++ b/include/arch/posix/driver/gpio.h
@@ -66,19 +66,19 @@ class GPIO {
 		inline void setup() {
 			pin_dir |= 0x0000ff;
 		}
-		inline void led_on(unsigned char id) {
+		inline void led_on(unsigned char id = 0) {
 			if (id <= pl7) {
 				pin_out |= (1 << id);
 			}
 			print_pinstate();
 		}
-		inline void led_off(unsigned char id) {
+		inline void led_off(unsigned char id = 0) {
 			if (id <= pl7) {
 				pin_out &= ~(1 << id);
 			}
 			print_pinstate();
 		}
-		inline void led_toggle(unsigned char id) {
+		inline void led_toggle(unsigned char id = 0) {
 			if (id <= pl7) {
 				if (pin_out & (1 << id)) {
 					led_off(id);
diff --git a/include/arch/stm32f446re-nucleo/driver/gpio.h b/include/arch/stm32f446re-nucleo/driver/gpio.h
index d2fb40a60fd911e98c2c884c03ce352132d410df..c07f96d10b83c52f11c40d4da938f61b8068d3a0 100644
--- a/include/arch/stm32f446re-nucleo/driver/gpio.h
+++ b/include/arch/stm32f446re-nucleo/driver/gpio.h
@@ -35,13 +35,13 @@ class GPIO {
 			gpio_mode_setup(GPIOA, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, GPIO5);
 		}
 #pragma GCC diagnostic ignored "-Wunused-parameter"
-		inline void led_on(unsigned char id) {
+		inline void led_on(unsigned char id = 0) {
 			gpio_set(GPIOA, GPIO5);
 		}
-		inline void led_off(unsigned char id) {
+		inline void led_off(unsigned char id = 0) {
 			gpio_clear(GPIOA, GPIO5);
 		}
-		inline void led_toggle(unsigned char id) {
+		inline void led_toggle(unsigned char id = 0) {
 			gpio_toggle(GPIOA, GPIO5);
 		}
 #pragma GCC diagnostic pop