Update 'USB protocol'

USB-protocol.md

@@ -137,9 +137,7 @@ Commands are typically a one-byte command ID, followed by a variable amount of d
   * Arguments: as many trigger step blobs (32 bits each) as specified in the settings blob (see below for both).
   * No response
 
-#### Blob formats
-
-##### Settings
+#### Settings blob
 
 This blob is 24 bytes in size.
 
@@ -193,7 +191,7 @@ The first byte of the voltage is equal to `floor(voltage * 39.2)`. In idle mode,
 
 The default settings blob used seems to be `01 04 00 00 00 90 d0 03 90 d0 03 e8 6e f3 00 00 f0 0f 0f 81 4b 32 01 00`.
 
-##### Trigger step
+#### Trigger step blob
 
 Every trigger step is 32 bits (4 bytes) in size. Unlike the above settings blob, this one does not distinguish different functionalities in different bytes as much. Therefore, we will represent it here as a single 32-bit bitmap. This bitmap is still sent as little-endian over the FTDI serial->FIFO USB protocol!
 
@@ -222,8 +220,6 @@ field: |LVL|0 |          pw_max '        |OVRL|0 |        ' pw_min          |IGN
 * 1: `HIRI2`: set to 1 trigger on channel 2 high or rising, 0 for low or falling. (Edge or level depends on bits 31 and 20)
 * 0: `HIRI1`: set to 1 trigger on channel 1 high or rising, 0 for low or falling. (Edge or level depends on bits 31 and 20)
 
-```
-
 ### Example transfers
 
 #### Spartan-3AN internal SPI flash read ID and status