Updated Clocking (markdown)

Clocking.md

@@ -4,8 +4,17 @@ HackRF clock signals are generated by the Si5351.  The plan so far:
 * optional clock input frequency: 10 MHz recommended (supports 10 to 40 MHz, or higher with division)
 * VCO frequency: 800 MHz (supports 600 to 900 MHz)
 * MAX2837 clock: 40 MHz
-* preferred MAX5864 clocks: 8, 10, 12.5, 16, 20 MHz
-* A DDR clock at double the MAX5864 will be delivered to the CPLD.
-* LPC43xx clock: 20 MHz (from integer-only output)
+* preferred MAX5864 clocks: 8, 10, 12.5, 20 MHz
+* A clock at quadruple the MAX5864 rate will be delivered to the CPLD.
+* LPC43xx clock: 12 MHz (from separate crystal so the ROM-based USB DFU will work)
 
-The LPC43xx will start up on its internal RC oscillator, activate the Si5351, and then switch to the 20 MHz clock coming from the Si5351.
+Future Si5351 output mapping:
+
+CLK0 -> none
+CLK1 -> none
+CLK2 -> RFFC5071
+CLK3 -> MAX2837
+CLK4 -> MAX5864
+CLK5 -> external clock output
+CLK6 -> CPLD
+CLK7 -> CPLD