diff --git a/TinyFrame/TF_Integration.c b/TinyFrame/TF_Integration.c
index 1828963..01fd4af 100644
--- a/TinyFrame/TF_Integration.c
+++ b/TinyFrame/TF_Integration.c
@@ -20,7 +20,7 @@ void TF_WriteImpl(TinyFrame *tf, const uint8_t *buff, uint32_t len)
 #define CHUNK 64 // same as TF_SENDBUF_LEN, so we should always have only one run of the loop
     int32_t total = (int32_t) len;
     while (total > 0) {
-        assert_param(osOK == osSemaphoreWait(semVcomTxReadyHandle, 5000));
+        assert_param(osOK == osSemaphoreWait(semVcomTxReadyHandle, 1000));
         uint16_t chunksize = (uint16_t) MIN(total, CHUNK);
         assert_param(USBD_OK == CDC_Transmit_FS((uint8_t *) buff, chunksize));
 
diff --git a/platform/hw_utils.c b/platform/hw_utils.c
index 5c0c9fb..a14c33b 100644
--- a/platform/hw_utils.c
+++ b/platform/hw_utils.c
@@ -2,14 +2,67 @@
 // Created by MightyPork on 2017/11/26.
 //
 
+#include "platform.h"
 #include <utils/avrlibc.h>
 #include "hw_utils.h"
 #include "macro.h"
 
-#define PINS_COUNT 16
+const uint32_t LL_SYSCFG_EXTI_PORTS[PORTS_COUNT] = {
+    LL_SYSCFG_EXTI_PORTA,
+    LL_SYSCFG_EXTI_PORTB,
+    LL_SYSCFG_EXTI_PORTC,
+    LL_SYSCFG_EXTI_PORTD,
+    LL_SYSCFG_EXTI_PORTE,
+#if PORTS_COUNT>5
+    LL_SYSCFG_EXTI_PORTF,
+#endif
+#if PORTS_COUNT>6
+    LL_SYSCFG_EXTI_PORTG,
+#endif
+};
+
+const uint32_t LL_SYSCFG_EXTI_LINES[16] = {
+    LL_SYSCFG_EXTI_LINE0,
+    LL_SYSCFG_EXTI_LINE1,
+    LL_SYSCFG_EXTI_LINE2,
+    LL_SYSCFG_EXTI_LINE3,
+    LL_SYSCFG_EXTI_LINE4,
+    LL_SYSCFG_EXTI_LINE5,
+    LL_SYSCFG_EXTI_LINE6,
+    LL_SYSCFG_EXTI_LINE7,
+    LL_SYSCFG_EXTI_LINE8,
+    LL_SYSCFG_EXTI_LINE9,
+    LL_SYSCFG_EXTI_LINE10,
+    LL_SYSCFG_EXTI_LINE11,
+    LL_SYSCFG_EXTI_LINE12,
+    LL_SYSCFG_EXTI_LINE13,
+    LL_SYSCFG_EXTI_LINE14,
+    LL_SYSCFG_EXTI_LINE15,
+};
+COMPILER_ASSERT(16 == ELEMENTS_IN_ARRAY(LL_SYSCFG_EXTI_LINES));
+
+const uint32_t LL_EXTI_LINES[16] = {
+    LL_EXTI_LINE_0,
+    LL_EXTI_LINE_1,
+    LL_EXTI_LINE_2,
+    LL_EXTI_LINE_3,
+    LL_EXTI_LINE_4,
+    LL_EXTI_LINE_5,
+    LL_EXTI_LINE_6,
+    LL_EXTI_LINE_7,
+    LL_EXTI_LINE_8,
+    LL_EXTI_LINE_9,
+    LL_EXTI_LINE_10,
+    LL_EXTI_LINE_11,
+    LL_EXTI_LINE_12,
+    LL_EXTI_LINE_13,
+    LL_EXTI_LINE_14,
+    LL_EXTI_LINE_15,
+};
+COMPILER_ASSERT(16 == ELEMENTS_IN_ARRAY(LL_EXTI_LINES));
 
 /** Pin number to LL bitfield mapping */
-static const uint32_t ll_pins[PINS_COUNT] = {
+const uint32_t LL_GPIO_PINS[16] = {
     LL_GPIO_PIN_0,
     LL_GPIO_PIN_1,
     LL_GPIO_PIN_2,
@@ -27,10 +80,10 @@ static const uint32_t ll_pins[PINS_COUNT] = {
     LL_GPIO_PIN_14,
     LL_GPIO_PIN_15,
 };
-COMPILER_ASSERT(16 == ELEMENTS_IN_ARRAY(ll_pins));
+COMPILER_ASSERT(16 == ELEMENTS_IN_ARRAY(LL_GPIO_PINS));
 
 /** Port number (A=0) to config struct pointer mapping */
-static GPIO_TypeDef * const port_periphs[] = {
+GPIO_TypeDef * const GPIO_PERIPHS[PORTS_COUNT] = {
     GPIOA,
     GPIOB,
     GPIOC,
@@ -43,20 +96,20 @@ static GPIO_TypeDef * const port_periphs[] = {
     GPIOG,
 #endif
 };
-COMPILER_ASSERT(PORTS_COUNT == ELEMENTS_IN_ARRAY(port_periphs));
+COMPILER_ASSERT(PORTS_COUNT == ELEMENTS_IN_ARRAY(GPIO_PERIPHS));
 
 /** Convert pin number to LL bitfield */
 uint32_t hw_pin2ll(uint8_t pin_number, bool *suc)
 {
     assert_param(suc != NULL);
 
-    if(pin_number >= PINS_COUNT) {
+    if(pin_number > 15) {
         dbg("Bad pin: %d", pin_number);
         // TODO proper report
         *suc = false;
         return 0;
     }
-    return ll_pins[pin_number];
+    return LL_GPIO_PINS[pin_number];
 }
 
 /** Convert port name (A,B,C...) to peripheral struct pointer */
@@ -71,7 +124,7 @@ GPIO_TypeDef *hw_port2periph(char port_name, bool *suc)
     }
 
     uint8_t num = (uint8_t) (port_name - 'A');
-    return port_periphs[num];
+    return GPIO_PERIPHS[num];
 }
 
 /** Convert a pin to resource handle */
@@ -85,7 +138,7 @@ Resource hw_pin2resource(char port_name, uint8_t pin_number, bool *suc)
         return R_NONE;
     }
 
-    if(pin_number >= PINS_COUNT) {
+    if(pin_number > 15) {
         dbg("Bad pin: %d", pin_number); // TODO proper report
         *suc = false;
         return R_NONE;
@@ -261,14 +314,27 @@ uint16_t pinmask_pack(uint16_t spread, uint16_t mask)
     return result;
 }
 
+/** Convert spread port pin number to a packed index using a mask */
+uint8_t pinmask_translate(uint16_t mask, uint8_t index)
+{
+    int cnt = 0;
+    for (int i = 0; i<16; i++) {
+        if (mask & (1<<i)) {
+            if (i == index) return (uint8_t) cnt;
+            cnt++;
+        }
+    }
+    return 0;
+}
+
 /** Configure unit pins as analog (part of unit teardown) */
 void hw_deinit_unit_pins(Unit *unit)
 {
     for (uint32_t rsc = R_PA0; rsc <= R_PF15; rsc++) {
         if (RSC_IS_HELD(unit->resources, rsc)) {
             rsc_dbg("Freeing pin %s", rsc_get_name((Resource)rsc));
-            GPIO_TypeDef *port = port_periphs[(rsc-R_PA0) / 16];
-            uint32_t ll_pin = ll_pins[(rsc-R_PA0)%16];
+            GPIO_TypeDef *port = GPIO_PERIPHS[(rsc-R_PA0) / 16];
+            uint32_t ll_pin = LL_GPIO_PINS[(rsc-R_PA0)%16];
             LL_GPIO_SetPinMode(port, ll_pin, LL_GPIO_MODE_ANALOG);
         }
     }
diff --git a/platform/hw_utils.h b/platform/hw_utils.h
index 678ca14..15baecd 100644
--- a/platform/hw_utils.h
+++ b/platform/hw_utils.h
@@ -11,6 +11,12 @@
 #include "platform.h"
 #include "resources.h"
 
+extern const uint32_t LL_SYSCFG_EXTI_PORTS[PORTS_COUNT];
+extern const uint32_t LL_SYSCFG_EXTI_LINES[16];
+extern GPIO_TypeDef * const GPIO_PERIPHS[PORTS_COUNT];
+extern const uint32_t LL_GPIO_PINS[16];
+extern const uint32_t LL_EXTI_LINES[16];
+
 /**
  * Convert pin number to LL driver bitfield for working with the pin.
  *
@@ -97,6 +103,13 @@ uint16_t pinmask_spread(uint16_t packed, uint16_t mask);
  */
 uint16_t pinmask_pack(uint16_t spread, uint16_t mask);
 
+/**
+ * Convert spread port pin number to a packed index using a mask
+ *
+ * eg. with a mask 0b1010 and index 3, the result is 1 (bit 1 of the packed - 0bX0)
+ */
+uint8_t pinmask_translate(uint16_t mask, uint8_t index);
+
 /**
  * Set all GPIO resources held by unit to analog.
  * This is a part of unit teardown.
diff --git a/platform/irq_dispatcher.c b/platform/irq_dispatcher.c
index 6935efe..ee87364 100644
--- a/platform/irq_dispatcher.c
+++ b/platform/irq_dispatcher.c
@@ -2,9 +2,29 @@
 // Created by MightyPork on 2018/01/14.
 //
 
-#include <utils/hexdump.h>
 #include "platform.h"
 #include "irq_dispatcher.h"
+#include "hw_utils.h"
+
+void * const EXTIS[16] = {
+    // dumym values for easier debug - those are used instead of periph addresses because EXTIs have no dedicated periph control blocks
+    (void *const) 0x9000,
+    (void *const) 0x9001,
+    (void *const) 0x9002,
+    (void *const) 0x9003,
+    (void *const) 0x9004,
+    (void *const) 0x9005,
+    (void *const) 0x9006,
+    (void *const) 0x9007,
+    (void *const) 0x9008,
+    (void *const) 0x9009,
+    (void *const) 0x900A,
+    (void *const) 0x900B,
+    (void *const) 0x900C,
+    (void *const) 0x900D,
+    (void *const) 0x900E,
+    (void *const) 0x900F,
+};
 
 struct cbslot {
     IrqCallback callback;
@@ -12,6 +32,8 @@ struct cbslot {
 };
 
 static struct callbacks_ {
+    struct cbslot exti[16];
+
     struct cbslot usart1;
     struct cbslot usart2;
     struct cbslot usart3;
@@ -51,9 +73,9 @@ void irqd_init(void)
 //    NVIC_EnableIRQ(RTC_IRQn);                   /*!< RTC Interrupt through EXTI Lines 17, 19 and 20                  */
 //    NVIC_EnableIRQ(FLASH_IRQn);                 /*!< FLASH global Interrupt                                          */
 //    NVIC_EnableIRQ(RCC_CRS_IRQn);               /*!< RCC & CRS global Interrupt                                      */
-//    NVIC_EnableIRQ(EXTI0_1_IRQn);               /*!< EXTI Line 0 and 1 Interrupt                                     */
-//    NVIC_EnableIRQ(EXTI2_3_IRQn);               /*!< EXTI Line 2 and 3 Interrupt                                     */
-//    NVIC_EnableIRQ(EXTI4_15_IRQn);              /*!< EXTI Line 4 to 15 Interrupt                                     */
+    NVIC_EnableIRQ(EXTI0_1_IRQn);               /*!< EXTI Line 0 and 1 Interrupt                                     */
+    NVIC_EnableIRQ(EXTI2_3_IRQn);               /*!< EXTI Line 2 and 3 Interrupt                                     */
+    NVIC_EnableIRQ(EXTI4_15_IRQn);              /*!< EXTI Line 4 to 15 Interrupt                                     */
 //    NVIC_EnableIRQ(TSC_IRQn);                   /*!< Touch Sensing Controller Interrupts                             */
     NVIC_EnableIRQ(DMA1_Channel1_IRQn);         /*!< DMA1 Channel 1 Interrupt                                        */
     NVIC_EnableIRQ(DMA1_Channel2_3_IRQn);       /*!< DMA1 Channel 2 and Channel 3 Interrupt                          */
@@ -107,6 +129,10 @@ static struct cbslot *get_slot_for_periph(void *periph)
         else if (periph == USART5) slot = &callbacks.usart5;
 #endif
 
+    else if (periph >= EXTIS[0] && periph <= EXTIS[15]) {
+        slot = &callbacks.exti[periph - EXTIS[0]];
+    }
+
         // --- DMA1 ---
     else if (periph == DMA1_Channel1) slot = &callbacks.dma1_1;
     else if (periph == DMA1_Channel2) slot = &callbacks.dma1_2;
@@ -154,12 +180,16 @@ void irqd_attach(void *periph, IrqCallback callback, void *arg)
     slot->arg = arg;
 }
 
-void irqd_detach(void *periph, IrqCallback callback)
+void* irqd_detach(void *periph, IrqCallback callback)
 {
+    void *oldArg = NULL;
     struct cbslot *slot = get_slot_for_periph(periph);
     if (slot->callback == callback) {
+        oldArg = slot->arg;
         slot->callback = NULL;
         slot->arg = NULL;
+
+        return oldArg;
     } else {
         trap("Detach IRQ %p() from %p but %p() bound instead", callback, periph, slot->callback);
     }
@@ -167,6 +197,8 @@ void irqd_detach(void *periph, IrqCallback callback)
 
 #define CALL_IRQ_HANDLER(slot) do { if (slot.callback) slot.callback(slot.arg); } while (0)
 
+// ------------ USARTS ------------
+
 void USART1_IRQHandler(void)
 {
     CALL_IRQ_HANDLER(callbacks.usart1);
@@ -177,32 +209,6 @@ void USART2_IRQHandler(void)
     CALL_IRQ_HANDLER(callbacks.usart2);
 }
 
-#if 0
-static bool usart_check_irq(USART_TypeDef *USARTx)
-{
-    uint32_t isrflags   = USARTx->ISR;
-    uint32_t cr1its     = USARTx->CR1;
-    uint32_t cr2its     = USARTx->CR2;
-    uint32_t cr3its     = USARTx->CR3;
-
-    if ((cr1its & USART_CR1_RTOIE) && (isrflags & USART_ISR_RTOF)) return true;
-    if ((cr1its & USART_CR1_RXNEIE) && (isrflags & USART_ISR_RXNE)) return true;
-    if ((cr1its & USART_CR1_TCIE) && (isrflags & USART_ISR_TC)) return true;
-    if ((cr1its & USART_CR1_TXEIE) && (isrflags & USART_ISR_TXE)) return true;
-    if ((cr3its & USART_CR3_EIE) && (isrflags & (USART_ISR_PE | USART_ISR_FE | USART_ISR_ORE | USART_ISR_NE))) return true;
-
-    if ((cr1its & USART_CR1_IDLEIE) && (isrflags & USART_ISR_IDLE)) return true;
-    if ((cr1its & USART_CR1_PEIE) && (isrflags & USART_ISR_PE)) return true;
-    if ((cr1its & USART_CR1_CMIE) && (isrflags & USART_ISR_CMF)) return true;
-    if ((cr1its & USART_CR1_EOBIE) && (isrflags & USART_ISR_EOBF)) return true;
-    if ((cr2its & USART_CR2_LBDIE) && (isrflags & USART_ISR_LBDF)) return true;
-    if ((cr3its & USART_CR3_CTSIE) && (isrflags & USART_ISR_CTS)) return true;
-    if ((cr3its & USART_CR3_WUFIE) && (isrflags & USART_ISR_WUF)) return true;
-
-    return false;
-}
-#endif
-
 void USART3_4_IRQHandler(void)
 {
     // we won't check the flags here, both can be pending and it's better to let the handler deal with it
@@ -210,6 +216,8 @@ void USART3_4_IRQHandler(void)
     CALL_IRQ_HANDLER(callbacks.usart4);
 }
 
+// ------------ DMA --------------
+
 void DMA1_Channel1_IRQHandler(void)
 {
     CALL_IRQ_HANDLER(callbacks.dma1_1);
@@ -229,43 +237,57 @@ void DMA1_Channel4_5_6_7_IRQHandler(void)
     if (LL_DMA_IsActiveFlag_GI7(DMA1)) CALL_IRQ_HANDLER(callbacks.dma1_7);
 }
 
-#if 0
-void WWDG_IRQHandler(void)
+// ------------ EXTI ------------
+
+static void fire_exti_cb(uint8_t start, uint8_t end)
 {
-    //
+    for (int i = start; i <= end; i++) {
+        if (LL_EXTI_IsActiveFlag_0_31(LL_EXTI_LINES[i])) {
+            CALL_IRQ_HANDLER(callbacks.exti[i]);
+        }
+    }
 }
 
-void PVD_VDDIO2_IRQHandler(void)
+void EXTI0_1_IRQHandler(void)
 {
-    //
+    fire_exti_cb(0, 1);
 }
 
-void RTC_IRQHandler(void)
+void EXTI2_3_IRQHandler(void)
 {
-    //
+    fire_exti_cb(2, 3);
 }
 
-void FLASH_IRQHandler(void)
+void EXTI4_15_IRQHandler(void)
+{
+    fire_exti_cb(4, 15);
+}
+
+
+// other ISRs...
+
+#if 0
+void WWDG_IRQHandler(void)
 {
     //
 }
 
-void RCC_CRS_IRQHandler(void)
+void PVD_VDDIO2_IRQHandler(void)
 {
     //
 }
 
-void EXTI0_1_IRQHandler(void)
+void RTC_IRQHandler(void)
 {
     //
 }
 
-void EXTI2_3_IRQHandler(void)
+void FLASH_IRQHandler(void)
 {
     //
 }
 
-void EXTI4_15_IRQHandler(void)
+void RCC_CRS_IRQHandler(void)
 {
     //
 }
diff --git a/platform/irq_dispatcher.h b/platform/irq_dispatcher.h
index e278998..9a6ebc0 100644
--- a/platform/irq_dispatcher.h
+++ b/platform/irq_dispatcher.h
@@ -7,6 +7,9 @@
 #ifndef GEX_F072_IRQ_DISPATCHER_H
 #define GEX_F072_IRQ_DISPATCHER_H
 
+// Dummy peripherals for use with the
+extern void * const EXTIS[16];
+
 /**
  * Initialize the interrupt dispatcher
  */
@@ -35,7 +38,8 @@ void irqd_attach(void *periph, IrqCallback callback, void *data);
  *
  * @param periph - peripheral we're attaching to
  * @param callback - callback to remove, if it doesn't match, do nothing
+ * @return the arg, if any
  */
-void irqd_detach(void *periph, IrqCallback callback);
+void* irqd_detach(void *periph, IrqCallback callback);
 
 #endif //GEX_F072_IRQ_DISPATCHER_H
diff --git a/platform/plat_compat.h b/platform/plat_compat.h
index 2ef70c4..bd6d7b3 100644
--- a/platform/plat_compat.h
+++ b/platform/plat_compat.h
@@ -24,7 +24,7 @@
 #define FLASH_SAVE_BUF_LEN  128 // Malloc'd buffer for saving to flash
 
 #define MSG_QUE_SLOT_SIZE 64 // FIXME this should be possible to lower, but there's some bug with bulk transfer / INI parser
-#define RX_QUE_CAPACITY    8 // TinyFrame rx queue size (64 bytes each)
+#define RX_QUE_CAPACITY    16 // TinyFrame rx queue size (64 bytes each)
 
 #define TF_MAX_PAYLOAD_RX 512 // TF max Rx payload
 #define TF_SENDBUF_LEN     64 // TF transmit buffer (can be less than a full frame)
diff --git a/tasks/sched_queue.h b/tasks/sched_queue.h
index e9aa118..ec4ebdd 100644
--- a/tasks/sched_queue.h
+++ b/tasks/sched_queue.h
@@ -30,10 +30,12 @@ struct sched_que_item {
     union {
         TF_ID frame_id; // typically used to pass frame id to the callback
         void *data1; // arbitrary pointer or int
+        uint32_t d32_1; // passing a number
     };
     /** Data word 2 */
     union {
         uint32_t d32; // passing a number
+        uint32_t d32_2; // passing a number
         uint8_t *buf; // uchar buffer
         const uint8_t *cbuf; // const uchar buffer
         const char *str; // string
@@ -43,6 +45,7 @@ struct sched_que_item {
     union {
         uint32_t len; // typically length of the buffer
         void *data3; // arbitrary pointer
+        uint32_t d32_3; // passing a number
     };
 };
 
diff --git a/tasks/task_msg.c b/tasks/task_msg.c
index 510ef9e..3ceaf71 100644
--- a/tasks/task_msg.c
+++ b/tasks/task_msg.c
@@ -17,11 +17,12 @@ static void que_safe_post(struct rx_sched_combined_que_item *slot)
     if (inIRQ()) {
         BaseType_t xHigherPriorityTaskWoken = pdFALSE;
         assert_param(pdPASS == xQueueSendFromISR(queMsgJobHandle, slot, &xHigherPriorityTaskWoken));
-        portYIELD_FROM_ISR(xHigherPriorityTaskWoken);
 
         #if USE_STACK_MONITOR
             count = (uint32_t) uxQueueMessagesWaitingFromISR(queMsgJobHandle);
         #endif
+
+        portYIELD_FROM_ISR(xHigherPriorityTaskWoken);
     } else {
         assert_param(pdPASS == xQueueSend(queMsgJobHandle, slot, MSG_QUE_POST_TIMEOUT));
 
diff --git a/units/digital_in/unit_din.c b/units/digital_in/unit_din.c
index d4df042..f279700 100644
--- a/units/digital_in/unit_din.c
+++ b/units/digital_in/unit_din.c
@@ -2,10 +2,12 @@
 // Created by MightyPork on 2017/11/25.
 //
 
-#include <stm32f072xb.h>
-#include "comm/messages.h"
 #include "unit_base.h"
+#include "utils/avrlibc.h"
+#include "platform/irq_dispatcher.h"
+#include "comm/messages.h"
 #include "unit_din.h"
+#include "tasks/task_msg.h"
 
 /** Private data structure */
 struct priv {
@@ -13,7 +15,11 @@ struct priv {
     uint16_t pins; // pin mask
     uint16_t pulldown; // pull-downs (default is pull-up)
     uint16_t pullup; // pull-ups
+    uint16_t trig_rise;
+    uint16_t trig_fall;
+    uint16_t trig_holdoff; // ms
 
+    uint16_t holdoff_countdowns[16];
     GPIO_TypeDef *port;
 };
 
@@ -32,7 +38,11 @@ static void DI_loadBinary(Unit *unit, PayloadParser *pp)
     priv->pulldown = pp_u16(pp);
     priv->pullup = pp_u16(pp);
 
-    dbg("load bin, pulldown = %X", priv->pulldown);
+    if (version >= 1) {
+        priv->trig_rise = pp_u16(pp);
+        priv->trig_fall = pp_u16(pp);
+        priv->trig_holdoff = pp_u16(pp);
+    }
 }
 
 /** Write to a binary buffer for storing in Flash */
@@ -40,12 +50,15 @@ static void DI_writeBinary(Unit *unit, PayloadBuilder *pb)
 {
     struct priv *priv = unit->data;
 
-    pb_u8(pb, 0); // version
+    pb_u8(pb, 1); // version
 
     pb_char(pb, priv->port_name);
     pb_u16(pb, priv->pins);
     pb_u16(pb, priv->pulldown);
     pb_u16(pb, priv->pullup);
+    pb_u16(pb, priv->trig_rise);
+    pb_u16(pb, priv->trig_fall);
+    pb_u16(pb, priv->trig_holdoff);
 }
 
 // ------------------------------------------------------------------------
@@ -68,6 +81,15 @@ static error_t DI_loadIni(Unit *unit, const char *key, const char *value)
     else if (streq(key, "pull-down")) {
         priv->pulldown = parse_pinmask(value, &suc);
     }
+    else if (streq(key, "trig-rise")) {
+        priv->trig_rise = parse_pinmask(value, &suc);
+    }
+    else if (streq(key, "trig-fall")) {
+        priv->trig_fall = parse_pinmask(value, &suc);
+    }
+    else if (streq(key, "trig-hold-off")) {
+        priv->trig_holdoff = (uint16_t) avr_atoi(value);
+    }
     else {
         return E_BAD_KEY;
     }
@@ -93,6 +115,15 @@ static void DI_writeIni(Unit *unit, IniWriter *iw)
     iw_comment(iw, "Pins with pull-down");
     iw_entry(iw, "pull-down", "%s", pinmask2str(priv->pulldown, unit_tmp512));
 
+    iw_comment(iw, "Trigger pins activated by rising edge");
+    iw_entry(iw, "trig-rise", "%s", pinmask2str(priv->trig_rise, unit_tmp512));
+
+    iw_comment(iw, "Trigger pins activated by falling edge");
+    iw_entry(iw, "trig-fall", "%s", pinmask2str(priv->trig_fall, unit_tmp512));
+
+    iw_comment(iw, "Trigger hold-off time (ms)");
+    iw_entry(iw, "trig-hold-off", "%d", (int)priv->trig_holdoff);
+
 #if PLAT_NO_FLOATING_INPUTS
     iw_comment(iw, "NOTE: Pins use pull-up by default.\r\n");
 #endif
@@ -112,9 +143,60 @@ static error_t DI_preInit(Unit *unit)
     priv->pulldown = 0x0000;
     priv->pullup = 0x0000;
 
+    priv->trig_rise = 0x0000;
+    priv->trig_fall = 0x0000;
+    priv->trig_holdoff = 20;
+
     return E_SUCCESS;
 }
 
+static void ID_SendTriggerReportToMaster(Job *job)
+{
+    Unit *unit = job->data1;
+
+    PayloadBuilder pb = pb_start(unit_tmp512, UNIT_TMP_LEN, NULL);
+    pb_u8(&pb, unit->callsign);
+    pb_u8(&pb, 0x00); // report type "Trigger"
+    pb_u16(&pb, (uint16_t) job->d32_2); // packed, 1 on the triggering pin
+    pb_u16(&pb, (uint16_t) job->d32_3); //
+    assert_param(pb.ok);
+    com_send_pb(MSG_UNIT_REPORT, &pb);
+}
+
+static void DI_handleExti(void *arg)
+{
+    Unit *unit = arg;
+    struct priv *priv = unit->data;
+    uint16_t snapshot = (uint16_t) priv->port->IDR;
+
+    uint16_t trigger_map = 0;
+
+    uint16_t mask = 1;
+    for (int i = 0; i < 16; i++, mask <<= 1) {
+        if ((priv->trig_rise|priv->trig_fall) & mask) {
+            if (LL_EXTI_ReadFlag_0_31(LL_EXTI_LINES[i])) {
+                if (priv->holdoff_countdowns[i] == 0) {
+                    trigger_map |= 1<<i;
+                    priv->holdoff_countdowns[i] = priv->trig_holdoff;
+                }
+
+                LL_EXTI_ClearFlag_0_31(LL_EXTI_LINES[i]);
+            }
+        }
+    }
+
+    // FIXME the job is not correctly handled, somehow. queue fills but is not collected
+    if (trigger_map != 0) {
+        Job j = {
+            .data1 = unit,
+            .d32_2 = pinmask_pack(trigger_map, priv->pins),
+            .d32_3 = snapshot,
+            .cb = ID_SendTriggerReportToMaster
+        };
+        scheduleJob(&j);
+    }
+}
+
 /** Finalize unit set-up */
 static error_t DI_init(Unit *unit)
 {
@@ -150,9 +232,29 @@ static error_t DI_init(Unit *unit)
             if (priv->pulldown & mask) pull = LL_GPIO_PULL_DOWN;
             if (priv->pullup & mask) pull = LL_GPIO_PULL_UP;
             LL_GPIO_SetPinPull(priv->port, ll_pin, pull);
+
+            if ((priv->trig_rise|priv->trig_fall) & mask) {
+                LL_EXTI_EnableIT_0_31(LL_EXTI_LINES[i]);
+
+                if (priv->trig_rise & mask) {
+                    LL_EXTI_EnableRisingTrig_0_31(LL_EXTI_LINES[i]);
+                }
+                if (priv->trig_fall & mask) {
+                    LL_EXTI_EnableFallingTrig_0_31(LL_EXTI_LINES[i]);
+                }
+
+                LL_SYSCFG_SetEXTISource(LL_SYSCFG_EXTI_PORTS[priv->port_name-'A'], LL_SYSCFG_EXTI_LINES[i]);
+
+                irqd_attach(EXTIS[i], DI_handleExti, unit);
+            }
         }
     }
 
+    // request ticks if we have triggers
+    if (priv->trig_rise|priv->trig_fall) {
+        unit->tick_interval = 1;
+    }
+
     return E_SUCCESS;
 }
 
@@ -160,8 +262,23 @@ static error_t DI_init(Unit *unit)
 /** Tear down the unit */
 static void DI_deInit(Unit *unit)
 {
+    struct priv *priv = unit->data;
+
     // pins are de-inited during teardown
 
+    if (unit->status == E_SUCCESS) {
+        // Detach EXTI handlers and disable interrupts
+        if (priv->trig_rise | priv->trig_fall) {
+            uint16_t mask = 1;
+            for (int i = 0; i < 16; i++, mask <<= 1) {
+                if ((priv->trig_rise | priv->trig_fall) & mask) {
+                    LL_EXTI_DisableIT_0_31(LL_EXTI_LINES[i]);
+                    irqd_detach(EXTIS[i], DI_handleExti);
+                }
+            }
+        }
+    }
+
     // Release all resources
     rsc_teardown(unit);
 
@@ -203,6 +320,22 @@ static error_t DI_handleRequest(Unit *unit, TF_ID frame_id, uint8_t command, Pay
     }
 }
 
+/**
+ * Decrement all the hold-off timers on tick
+ *
+ * @param unit
+ */
+static void DI_updateTick(Unit *unit)
+{
+    struct priv *priv = unit->data;
+
+    for (int i = 0; i < 16; i++) {
+        if (priv->holdoff_countdowns[i] > 0) {
+            priv->holdoff_countdowns[i]--;
+        }
+    }
+}
+
 // ------------------------------------------------------------------------
 
 /** Unit template */
@@ -220,4 +353,5 @@ const UnitDriver UNIT_DIN = {
     .deInit = DI_deInit,
     // Function
     .handleRequest = DI_handleRequest,
+    .updateTick = DI_updateTick,
 };
diff --git a/units/usart/unit_usart.c b/units/usart/unit_usart.c
index 40983fc..f5f2d00 100644
--- a/units/usart/unit_usart.c
+++ b/units/usart/unit_usart.c
@@ -19,7 +19,8 @@ static void UUSART_SendReceivedDataToMaster(Job *job)
     uint32_t readpos = job->d32;
     uint32_t count = job->len;
 
-    // TODO modify TF to allow writing in multiple chunks to avoid this useless buffer copying
+    // TODO use TF's Multipart sending
+    // TODO add API for building reports
     PayloadBuilder pb = pb_start(unit_tmp512, UNIT_TMP_LEN, NULL);
     pb_u8(&pb, unit->callsign);
     pb_u8(&pb, 0x00); // report type "Data received"