diff --git a/docs/Protocol.md b/docs/Protocol.md
index c6fce029..f73a195a 100644
--- a/docs/Protocol.md
+++ b/docs/Protocol.md
@@ -115,7 +115,7 @@ Declaring constants
 Constants can also be exported. For example, the following:
 
 ```
-DECL_CONSTANT(SERIAL_BAUD, 250000);
+DECL_CONSTANT("SERIAL_BAUD", 250000);
 ```
 
 would export a constant named "SERIAL_BAUD" with a value of 250000
diff --git a/src/atsam/adc.c b/src/atsam/adc.c
index d5e74676..816b388e 100644
--- a/src/atsam/adc.c
+++ b/src/atsam/adc.c
@@ -27,7 +27,7 @@ static const uint8_t adc_pins[] = {
 };
 
 #define ADC_FREQ_MAX 20000000
-DECL_CONSTANT(ADC_MAX, 4095);
+DECL_CONSTANT("ADC_MAX", 4095);
 
 struct gpio_adc
 gpio_adc_setup(uint8_t pin)
diff --git a/src/atsam/hard_pwm.c b/src/atsam/hard_pwm.c
index 7d1881a6..0b238b24 100644
--- a/src/atsam/hard_pwm.c
+++ b/src/atsam/hard_pwm.c
@@ -54,7 +54,7 @@ static const struct gpio_pwm_info pwm_regs[] = {
 
 #define MAX_PWM 255
 
-DECL_CONSTANT(PWM_MAX, MAX_PWM);
+DECL_CONSTANT("PWM_MAX", MAX_PWM);
 
 struct gpio_pwm
 gpio_pwm_setup(uint8_t pin, uint32_t cycle_time, uint8_t val)
diff --git a/src/atsam/main.c b/src/atsam/main.c
index b6be2864..0bb9ff83 100644
--- a/src/atsam/main.c
+++ b/src/atsam/main.c
@@ -10,7 +10,7 @@
 #include "internal.h" // WDT
 #include "sched.h" // sched_main
 
-DECL_CONSTANT(MCU, CONFIG_MCU);
+DECL_CONSTANT_STR("MCU", CONFIG_MCU);
 
 
 /****************************************************************
diff --git a/src/atsam/sam4e_afec.c b/src/atsam/sam4e_afec.c
index 002e092f..4c78e958 100644
--- a/src/atsam/sam4e_afec.c
+++ b/src/atsam/sam4e_afec.c
@@ -51,7 +51,7 @@ gpio_adc_to_afec_chan(struct gpio_adc g)
 }
 
 #define ADC_FREQ_MAX 6000000UL
-DECL_CONSTANT(ADC_MAX, 4095);
+DECL_CONSTANT("ADC_MAX", 4095);
 
 static int
 init_afec(Afec* afec) {
diff --git a/src/atsamd/adc.c b/src/atsamd/adc.c
index 26465c2d..8d25d2f4 100644
--- a/src/atsamd/adc.c
+++ b/src/atsamd/adc.c
@@ -37,7 +37,7 @@ static const uint8_t adc_pins[] = {
 };
 #endif
 
-DECL_CONSTANT(ADC_MAX, 4095);
+DECL_CONSTANT("ADC_MAX", 4095);
 
 static struct gpio_adc gpio_adc_pin_to_struct(uint8_t pin)
 {
diff --git a/src/atsamd/hard_pwm.c b/src/atsamd/hard_pwm.c
index 3f510520..0b3a6ba4 100644
--- a/src/atsamd/hard_pwm.c
+++ b/src/atsamd/hard_pwm.c
@@ -41,7 +41,7 @@ static const struct gpio_pwm_info pwm_regs[] = {
 
 #define MAX_PWM 255
 
-DECL_CONSTANT(PWM_MAX, MAX_PWM);
+DECL_CONSTANT("PWM_MAX", MAX_PWM);
 
 struct gpio_pwm
 gpio_pwm_setup(uint8_t pin, uint32_t cycle_time, uint8_t val)
diff --git a/src/atsamd/main.c b/src/atsamd/main.c
index 5a5a374d..c7dbe9fd 100644
--- a/src/atsamd/main.c
+++ b/src/atsamd/main.c
@@ -8,7 +8,7 @@
 #include "internal.h" // NVIC_SystemReset
 #include "sched.h" // sched_main
 
-DECL_CONSTANT(MCU, CONFIG_MCU);
+DECL_CONSTANT_STR("MCU", CONFIG_MCU);
 
 // Return the start of memory available for dynamic allocations
 void *
diff --git a/src/avr/adc.c b/src/avr/adc.c
index 3087dce1..8b478d08 100644
--- a/src/avr/adc.c
+++ b/src/avr/adc.c
@@ -36,7 +36,7 @@ static const uint8_t adc_pins[] PROGMEM = {
 enum { ADMUX_DEFAULT = 0x40 };
 enum { ADC_ENABLE = (1<<ADPS0)|(1<<ADPS1)|(1<<ADPS2)|(1<<ADEN)|(1<<ADIF) };
 
-DECL_CONSTANT(ADC_MAX, 1023);
+DECL_CONSTANT("ADC_MAX", 1023);
 
 struct gpio_adc
 gpio_adc_setup(uint8_t pin)
diff --git a/src/avr/hard_pwm.c b/src/avr/hard_pwm.c
index a6609313..01d0bd9e 100644
--- a/src/avr/hard_pwm.c
+++ b/src/avr/hard_pwm.c
@@ -74,7 +74,7 @@ static const struct gpio_pwm_info pwm_regs[] PROGMEM = {
 #endif
 };
 
-DECL_CONSTANT(PWM_MAX, 255);
+DECL_CONSTANT("PWM_MAX", 255);
 
 struct gpio_pwm
 gpio_pwm_setup(uint8_t pin, uint32_t cycle_time, uint8_t val)
diff --git a/src/avr/main.c b/src/avr/main.c
index 57aa3c01..0523af41 100644
--- a/src/avr/main.c
+++ b/src/avr/main.c
@@ -12,7 +12,7 @@
 #include "irq.h" // irq_enable
 #include "sched.h" // sched_main
 
-DECL_CONSTANT(MCU, CONFIG_MCU);
+DECL_CONSTANT_STR("MCU", CONFIG_MCU);
 
 
 /****************************************************************
diff --git a/src/avr/timer.c b/src/avr/timer.c
index e8880a64..fb8738cc 100644
--- a/src/avr/timer.c
+++ b/src/avr/timer.c
@@ -16,7 +16,7 @@
  * Low level timer code
  ****************************************************************/
 
-DECL_CONSTANT(CLOCK_FREQ, CONFIG_CLOCK_FREQ);
+DECL_CONSTANT("CLOCK_FREQ", CONFIG_CLOCK_FREQ);
 
 // Return the number of clock ticks for a given number of microseconds
 uint32_t
diff --git a/src/basecmd.c b/src/basecmd.c
index f554c13e..95511885 100644
--- a/src/basecmd.c
+++ b/src/basecmd.c
@@ -258,7 +258,7 @@ command_get_uptime(uint32_t *args)
 DECL_COMMAND_FLAGS(command_get_uptime, HF_IN_SHUTDOWN, "get_uptime");
 
 #define SUMSQ_BASE 256
-DECL_CONSTANT(STATS_SUMSQ_BASE, SUMSQ_BASE);
+DECL_CONSTANT("STATS_SUMSQ_BASE", SUMSQ_BASE);
 
 void
 stats_update(uint32_t start, uint32_t cur)
diff --git a/src/command.h b/src/command.h
index 92315f38..c924e59d 100644
--- a/src/command.h
+++ b/src/command.h
@@ -16,8 +16,8 @@
 #define HF_IN_SHUTDOWN   0x01   // Handler can run even when in emergency stop
 
 // Declare a constant exported to the host
-#define DECL_CONSTANT(NAME, VALUE)              \
-    _DECL_CONSTANT(NAME, VALUE)
+#define DECL_CONSTANT(NAME, VALUE) _DECL_CONSTANT(NAME, __stringify(VALUE))
+#define DECL_CONSTANT_STR(NAME, VALUE) _DECL_CONSTANT(NAME, VALUE)
 
 // Send an output message (and declare a static message type for it)
 #define output(FMT, args...)                    \
@@ -88,8 +88,8 @@ uint8_t ctr_lookup_static_string(const char *str);
 #define _DECL_COMMAND(FUNC, FLAGS, MSG)                                 \
     DECL_CTR("_DECL_COMMAND " __stringify(FUNC) " " __stringify(FLAGS) " " MSG)
 
-#define _DECL_CONSTANT(NAME, VALUE)                                     \
-    DECL_CTR("_DECL_CONSTANT " __stringify(NAME) " " __stringify(VALUE))
+#define _DECL_CONSTANT(NAME, VALUE)             \
+    DECL_CTR("_DECL_CONSTANT " NAME " " VALUE)
 
 #define _DECL_ENCODER(FMT) ({                   \
     DECL_CTR("_DECL_ENCODER " FMT);             \
diff --git a/src/generic/armcm_timer.c b/src/generic/armcm_timer.c
index f1bc11fa..a9c8ab9f 100644
--- a/src/generic/armcm_timer.c
+++ b/src/generic/armcm_timer.c
@@ -11,7 +11,7 @@
 #include "command.h" // shutdown
 #include "sched.h" // sched_timer_dispatch
 
-DECL_CONSTANT(CLOCK_FREQ, CONFIG_CLOCK_FREQ);
+DECL_CONSTANT("CLOCK_FREQ", CONFIG_CLOCK_FREQ);
 
 // Return the number of clock ticks for a given number of microseconds
 uint32_t
diff --git a/src/generic/serial_irq.c b/src/generic/serial_irq.c
index 76304323..c2b23864 100644
--- a/src/generic/serial_irq.c
+++ b/src/generic/serial_irq.c
@@ -19,8 +19,8 @@
 static uint8_t receive_buf[RX_BUFFER_SIZE], receive_pos;
 static uint8_t transmit_buf[96], transmit_pos, transmit_max;
 
-DECL_CONSTANT(SERIAL_BAUD, CONFIG_SERIAL_BAUD);
-DECL_CONSTANT(RECEIVE_WINDOW, RX_BUFFER_SIZE);
+DECL_CONSTANT("SERIAL_BAUD", CONFIG_SERIAL_BAUD);
+DECL_CONSTANT("RECEIVE_WINDOW", RX_BUFFER_SIZE);
 
 // Rx interrupt - store read data
 void
diff --git a/src/generic/timer_irq.c b/src/generic/timer_irq.c
index f7e255e6..40e9336b 100644
--- a/src/generic/timer_irq.c
+++ b/src/generic/timer_irq.c
@@ -11,7 +11,7 @@
 #include "command.h" // shutdown
 #include "sched.h" // sched_timer_dispatch
 
-DECL_CONSTANT(CLOCK_FREQ, CONFIG_CLOCK_FREQ);
+DECL_CONSTANT("CLOCK_FREQ", CONFIG_CLOCK_FREQ);
 
 // Return the number of clock ticks for a given number of microseconds
 uint32_t
diff --git a/src/gpiocmds.c b/src/gpiocmds.c
index 105d9d88..1d48a40e 100644
--- a/src/gpiocmds.c
+++ b/src/gpiocmds.c
@@ -107,7 +107,7 @@ DECL_COMMAND(command_set_digital_out, "set_digital_out pin=%u value=%c");
  ****************************************************************/
 
 #define MAX_SOFT_PWM 256
-DECL_CONSTANT(SOFT_PWM_MAX, MAX_SOFT_PWM);
+DECL_CONSTANT("SOFT_PWM_MAX", MAX_SOFT_PWM);
 
 struct soft_pwm_s {
     struct timer timer;
diff --git a/src/linux/analog.c b/src/linux/analog.c
index 990f6c4a..5011f531 100644
--- a/src/linux/analog.c
+++ b/src/linux/analog.c
@@ -13,7 +13,7 @@
 #include "internal.h" // report_errno
 #include "sched.h" // sched_shutdown
 
-DECL_CONSTANT(ADC_MAX, 4095); // Assume 12bit adc
+DECL_CONSTANT("ADC_MAX", 4095); // Assume 12bit adc
 
 #define IIO_PATH "/sys/bus/iio/devices/iio:device0/in_voltage%d_raw"
 
diff --git a/src/linux/main.c b/src/linux/main.c
index f351ec1f..4c5478eb 100644
--- a/src/linux/main.c
+++ b/src/linux/main.c
@@ -13,7 +13,7 @@
 #include "internal.h" // console_setup
 #include "sched.h" // sched_main
 
-DECL_CONSTANT(MCU, "linux");
+DECL_CONSTANT_STR("MCU", "linux");
 
 
 /****************************************************************
diff --git a/src/linux/pca9685.c b/src/linux/pca9685.c
index 0b9ff73d..14eefb15 100644
--- a/src/linux/pca9685.c
+++ b/src/linux/pca9685.c
@@ -136,7 +136,7 @@ struct i2cpwm_s {
     uint32_t max_duration;
 };
 
-DECL_CONSTANT(PCA9685_MAX, VALUE_MAX);
+DECL_CONSTANT("PCA9685_MAX", VALUE_MAX);
 
 static uint_fast8_t
 pca9685_end_event(struct timer *timer)
diff --git a/src/linux/timer.c b/src/linux/timer.c
index faf6a5d2..15e5ab76 100644
--- a/src/linux/timer.c
+++ b/src/linux/timer.c
@@ -106,7 +106,7 @@ timer_check_periodic(struct timespec *ts)
  * Timers
  ****************************************************************/
 
-DECL_CONSTANT(CLOCK_FREQ, CONFIG_CLOCK_FREQ);
+DECL_CONSTANT("CLOCK_FREQ", CONFIG_CLOCK_FREQ);
 
 // Return the number of clock ticks for a given number of microseconds
 uint32_t
diff --git a/src/lpc176x/adc.c b/src/lpc176x/adc.c
index e5ce6a96..1f5fbbde 100644
--- a/src/lpc176x/adc.c
+++ b/src/lpc176x/adc.c
@@ -23,7 +23,7 @@ static const uint8_t adc_pin_funcs[] = {
 };
 
 #define ADC_FREQ_MAX 13000000
-DECL_CONSTANT(ADC_MAX, 4095);
+DECL_CONSTANT("ADC_MAX", 4095);
 
 // The lpc176x adc is extremely noisy. Implement a 5 entry median
 // filter to weed out obviously incorrect readings.
diff --git a/src/lpc176x/main.c b/src/lpc176x/main.c
index 82777bc1..1147faec 100644
--- a/src/lpc176x/main.c
+++ b/src/lpc176x/main.c
@@ -8,7 +8,7 @@
 #include "command.h" // DECL_CONSTANT
 #include "sched.h" // sched_main
 
-DECL_CONSTANT(MCU, "lpc176x");
+DECL_CONSTANT_STR("MCU", "lpc176x");
 
 
 /****************************************************************
diff --git a/src/pru/adc.c b/src/pru/adc.c
index 62aca60a..81ec7fe3 100644
--- a/src/pru/adc.c
+++ b/src/pru/adc.c
@@ -16,7 +16,7 @@
  * Analog to Digital Converter (ADC) pins
  ****************************************************************/
 
-DECL_CONSTANT(ADC_MAX, 4095);
+DECL_CONSTANT("ADC_MAX", 4095);
 
 static void
 adc_full_reset(void)
diff --git a/src/pru/main.c b/src/pru/main.c
index 6019d087..88e622a6 100644
--- a/src/pru/main.c
+++ b/src/pru/main.c
@@ -17,7 +17,7 @@
 #include "internal.h" // SHARED_MEM
 #include "sched.h" // sched_main
 
-DECL_CONSTANT(MCU, "pru");
+DECL_CONSTANT_STR("MCU", "pru");
 
 
 /****************************************************************
diff --git a/src/stepper.c b/src/stepper.c
index 8f4ec816..d8129c4a 100644
--- a/src/stepper.c
+++ b/src/stepper.c
@@ -13,7 +13,7 @@
 #include "sched.h" // struct timer
 #include "stepper.h" // command_config_stepper
 
-DECL_CONSTANT(STEP_DELAY, CONFIG_STEP_DELAY);
+DECL_CONSTANT("STEP_DELAY", CONFIG_STEP_DELAY);
 
 
 /****************************************************************
diff --git a/src/stm32f1/adc.c b/src/stm32f1/adc.c
index 8eda4f8f..fcdcb911 100644
--- a/src/stm32f1/adc.c
+++ b/src/stm32f1/adc.c
@@ -14,7 +14,7 @@
 #include "stm32f1xx_ll_gpio.h" // LL_GPIO_SetPinMode
 #include "sched.h" // sched_shutdown
 
-DECL_CONSTANT(ADC_MAX, 4095);
+DECL_CONSTANT("ADC_MAX", 4095);
 
 #define ADC_DELAY (240 * 8)
 
diff --git a/src/stm32f1/main.c b/src/stm32f1/main.c
index 3abb03a3..258578da 100644
--- a/src/stm32f1/main.c
+++ b/src/stm32f1/main.c
@@ -19,7 +19,7 @@
 #include "stm32f1xx_ll_spi.h"
 #include "sched.h" // sched_main
 
-DECL_CONSTANT(MCU, "stm32f103");
+DECL_CONSTANT_STR("MCU", "stm32f103");
 
 
 /****************************************************************