formatting corrections

UNIT_DO.md

@@ -5,38 +5,40 @@
 - Supports generating output pulses of precise length.
 
 Pins are ordered in a descending order (DOWNTO) and accessed in a packed format,
-e.g. if pins 1 and 4 are selected (0b10010 on the port), the control word has
-two bits (4)(1) and e.g. 0b10 means pin 4, 0b11 both. This makes accessing the
+e.g. if pins 1 and 4 are selected (`0b10010` on the port), the control word has
+two bits `(4)(1)` and e.g. `0b10` means pin 4, `0b11` both. This makes accessing the
 block of pins easier, e.g. when using them to drive a parallel bus.
 
 ## Commands
 
-### WRITE
+### WRITE (0x00)
 Write a value to all defined pins.
 
 *Payload:*
 - u16 - new value (packed)
 
-### SET
+### SET (0x01)
 Set pins high
 
 *Payload:*
 - u16 - pins to set high (packed)
 
-### CLEAR
+### CLEAR (0x02)
 Set pins low
 
 *Payload:*
 - u16 - pins to set low (packed)
 
-### TOGGLE
+### TOGGLE (0x03)
 Toggle selected pins (high - low)
 
 *Payload:*
 - u16 - pins to toggle (packed)
 
-### PULSE
-Send a pulse. The start will be aligned to 1 us or 1 ms (based on pulse length) of the internal timebase to ensure the highest length precision. (This alignment reduces time jitter.)
+### PULSE (0x04)
+Send a pulse.
+
+The start will be aligned to 1 us or 1 ms (based on pulse length) of the internal timebase to ensure the highest length precision. This alignment reduces jitter in the pulse duration. A jitter of the pulse start time is less significant, as there's already some unpredictable delay caused by the USB connection and the PC OS scheduler.
 
 *Payload:*
 - u16 - pins to generate the pulse on (packed)
@@ -44,7 +46,7 @@ Send a pulse. The start will be aligned to 1 us or 1 ms (based on pulse length)
 - u8 - range (0 - milliseconds, 1 - microseconds)
 - u16 - duration in the selected range
 
-*NOTE:* The microsecond range supports durations only up to 999 (1 ms), higher
+*NOTE:* The microsecond range supports durations only up to 999 us, higher
 numbers will be divided by 1000 and use the millisecond range instead.
 
 ## Events