--- a/dac.pio	Wed Feb 26 11:03:59 2025 +1030
+++ b/dac.pio	Thu Feb 27 13:58:37 2025 +1030
@@ -7,6 +7,7 @@
 ; Need 1 side set pin, the clock
 .side_set 1
 
+PUBLIC init:
 ; Clock in a 0 byte
     mov pins, null side 0
     nop side 1
@@ -17,12 +18,6 @@
 .wrap_target
     out pins 8 side 0 [1]
     nop side 1        [1]
-    out pins 8 side 0 [1]
-    nop side 1        [1]
-    out pins 8 side 0 [1]
-    nop side 1        [1]
-    out pins 8 side 0 [1]
-    nop side 1        [1]
 .wrap
 
 % c-sdk {
@@ -38,22 +33,27 @@
     for (int i = 0; i < 9; i++)
         pio_gpio_init(pio, pin + i);
 
+    // Configure sideset pin to use for clock
+    sm_config_set_sideset_pins(&c, pin + 8);
+
     sm_config_set_out_shift(
         &c,
         true,  // Shift-to-right
         true,  // Autopull enabled
-        32     // Autopull threshold (bits!)
+        8      // Autopull threshold (bits!)
     );
 
-    // Configure sideset pin to use for clock
-    sm_config_set_sideset_pins(&c, pin + 8);
-
     // We only send, so disable the RX FIFO to make the TX FIFO deeper.
     sm_config_set_fifo_join(&c, PIO_FIFO_JOIN_TX);
 
     sm_config_set_clkdiv(&c, clkdiv);
 
-    // Load our configuration
+    // Load our configuration (but don't start)
     pio_sm_init(pio, sm, offset, &c);
 }
+
+static inline uint dac_reset_instr (uint offset) {
+    // encode a "jmp init side 0" instruction for the state machine
+    return pio_encode_jmp (offset + dac_offset_init) | pio_encode_sideset (1, 0);
+}
 %}