Update README.md

Function Generator/README.md

@@ -1,18 +1,18 @@
 # Function Generator on a RP2040. #
 * Features:
   * Direct Digital Synthesis (DDS) Function Generator
-  * Serial over USB interface (Putty)
+  * Independant control of either channel through Putty terminal session over USB port
   * Dual 8 bit R-2R Digital to Analog converter
   * 1Hz => 1MHz frequency range.
-  * Variable output level (requires MCP41020 dual digital potentiometer with SPI interface)
-  * Analog clock simulator
-  * Target device = Pico (also works on Pimoroni PGA2040)
+  * X-Y mode for Analog clock
+  * Variable output level 0=>100%
   * External, 3 digit, SPI display
-  * Independant control of either channel through Putty terminal session over USB port
+  * Target device = Pico (also works on Pimoroni PGA2040)  
  
 * Limitations:
   * USB serial requires Windows (10 or later)
   * Phase sync mechanism not effective at high frequencies
+  * Target device must be overclocked for 1MHz operation
 
 **Two independanty controled, phase locked, DMA channels...**
 
@@ -22,7 +22,7 @@
 
 ![Hardware](https://github.com/oddwires/RP2040/blob/master/Function%20Generator/Images/FunctionGenerator.jpg)
 
-**Analog Clock Simulator using X-Y mode on a CRT Oscilloscope...**
+**X-Y mode for Analog Clock Simulator on a CRT Oscilloscope...**
 
 ![Hardware](https://github.com/oddwires/RP2040/blob/master/Function%20Generator/Images/IMG_E1221.JPG)