--- a/modulator.c	Tue Feb 25 15:56:49 2025 +1030
+++ b/modulator.c	Tue Feb 25 16:47:00 2025 +1030
@@ -16,7 +16,7 @@
 ** Create modulation shape
 **
 */
-//#define WITH_TRIGGER
+#define WITH_TRIGGER
 
 #include <stdio.h>
 #include <string.h>
@@ -51,8 +51,9 @@
 // Base of ctrl pins
 #define CTRLOUT_GPIO	16
 // PWM output pin
-#define TRIGOUT_GPIO	23
+#define TRIGOUT_GPIO	22
 // PIO SM trigger input pin (connected to above for testing)
+// Also outputs trigger on next pin
 #define TRIGIN_GPIO	27
 
 // Pulse control bits
@@ -119,7 +120,6 @@
   dma_channel_set_read_addr(ctrl_dma_chan, pulse_ctrl, true);
 }
 
-
 void
 pwm_wrap(void) {
   pwm_clear_irq(slice_num);
@@ -426,6 +426,7 @@
     uint trigger_sm = pio_claim_unused_sm(pulse_pio, true);
     trigger_program_init(pulse_pio, trigger_sm, trigger_pio_sm_offset, TRIGIN_GPIO, 2);
 #endif
+
     //
     // Setup PWM
     // Used here to output a trigger which gets fed back into the trigger SM

--- a/trigger.pio	Tue Feb 25 15:56:49 2025 +1030
+++ b/trigger.pio	Tue Feb 25 16:47:00 2025 +1030
@@ -3,15 +3,19 @@
 ;
 
 .program trigger
-.define TRIGGER_IRQ 0
+.define DAC_TRIGGER_IRQ 0
+.define CTRL_TRIGGER_IRQ 1
+; Use 1 side set pin for debugging
+.side_set 1
 
 .wrap_target
 ; Wait for trigger to be low
-    wait 0 pin 0
+    wait 0 pin 0 side 0
 ; Wait for rising edge
-    wait 1 pin 0
-; Signal other state machine
-    irq nowait TRIGGER_IRQ
+    wait 1 pin 0 side 0
+; Signal other state machines
+    irq nowait DAC_TRIGGER_IRQ side 1
+    irq nowait CTRL_TRIGGER_IRQ side 1
 .wrap
 
 % c-sdk {
@@ -25,6 +29,13 @@
     // Connect this GPIO to this PIO block
     pio_gpio_init(pio, pin);
 
+    // Configure side pin mapping to point to debug pin
+    sm_config_set_sideset_pins(&c, pin + 1);
+    // Set to output
+    pio_sm_set_consecutive_pindirs(pio, sm, pin + 1, 1, true);
+    // Connect this GPIO to this PIO block
+    pio_gpio_init(pio, pin + 1);
+
     sm_config_set_clkdiv(&c, clkdiv);
 
     // Load our configuration, and start the program from the beginning