Spiffed up the VT100 demo pages

devices/pc8080/machine/vt100/README.md

@@ -15,12 +15,41 @@ This is a PCjs work-in-progress emulation of another 8080-based machine: the VT1
 
 Unlike other VT100 emulators, it is not simply an emulation of VT100 protocols.  It is a simulation of the original VT100
 machine, running the [VT100 Firmware](/devices/pc8080/rom/vt100/) inside the [PC8080](/modules/pc8080/) CPU emulator.
+A [Debugger Configuration](/devices/pc8080/machine/vt100/debugger/) is also available.
 
 Admittedly, terminals aren't that useful in isolation, since they're designed to be connected to other (host) machines.
 But once this PCjs VT100 Terminal simulation is fully operational, you can expect to see it used in conjunction with a variety
 of other PCjs machines. 
 
-For now, play with the [Debugger Configuration](/devices/pc8080/machine/vt100/debugger/), which also provides information
-about VT100 internals and links to other technical resources.
-
 {% include machine.html id="vt100" %}
+
+VT100 Keys
+----------
+
+Function keys are mapped as follows:
+
+- F1: PF1
+- F2: PF2
+- F3: PF3
+- F4: PF4
+- F6: BREAK
+- F7: LINE FEED
+- F8: NO SCROLL
+- F9: SET-UP
+
+From the SET-UP screen, you can press **4** to switch to LOCAL mode and verify local operation of most VT100
+keys.  The following keys have special meaning inside SET-UP Mode.
+
+### SET-UP Mode Keys
+
+- 0: RESET
+- 2: SET/CLEAR TAB
+- 3: CLEAR ALL TABS
+- 4: ONLINE/LOCAL
+- 5: SET-UP A/B
+- 6: TOGGLE FEATURE
+- 7: TRANSMIT SPEED
+- 8: RECEIVE SPEED
+- 9: 80/132 COLUMNS
+- SHIFT-S: Save SET-UP Features
+- SHIFT-R: Restore SET-UP Features