README remove most fn/mode references for simplicity

Author: clockspot

README.md

@@ -4,65 +4,65 @@
 
 **A digital clock for the Arduino Nano and a nixie tube display.**
 
-* Features a perpetual calendar, day counter, sunrise/sunset, alarm, timer, and automatic DST change.
+* Features perpetual calendar with day counter and sunrise/sunset, alarm with skip/snooze, and countdown timer.
+* Supports automatic DST change, hourly chimes, LED lighting control, piezo beeper, and switchable relay.
 * Supports four- or six-digit displays of Nixie tubes multiplexed in pairs via two SN74141 driver chips.
-* Supports switchable LED backlighting, a piezo beeper, and a relay (to switch an appliance or impulse device).
-* Timekeeping currently requires a DS3231 real-time clock via I2C, which is battery-backed and thermocompensated.
+* Timekeeping requires a DS3231 real-time clock via I2C, which is battery-backed and thermocompensated.
 * Written for [RLB Designs’](http://rlb-designs.com/) Universal Nixie Driver Board (UNDB), with LED control for v8+ and relay for v9+.
 
-[The latest release can be downloaded here.](https://github.com/clockspot/arduino-nixie/releases/latest) Skip to [Hardware Configuration](#hardware-configuration) for details on how to tweak the sketch.
+[The latest release can be downloaded here.](https://github.com/clockspot/arduino-nixie/releases/latest) Skip to [Hardware Configuration](#hardware-configuration) for details on tweaking the sketch.
 
 ## Operating Instructions, v1.6.0
 
 When first powered up, the clock will display its software version (as of v1.6). [Instructions for earlier versions are here.](https://github.com/clockspot/arduino-nixie/releases)
 
-Press **Select** to cycle through the clock’s modes: [Time](#time), [Calendar](#calendar), [Alarm](#alarm), and [Timer](#timer).
+Press **Select** to cycle through [Time of Day](#time-of-day), [Calendar](#calendar), [Alarm](#alarm), and [Countdown Timer](#countdown-timer).
 
 To set something, simply hold **Select** until it flashes; use **Up/Down** to set, and **Select** to save.
 
-### Time Mode
+### Time of Day
 
-This displays the time of day. You can specify 12h or 24h format in the [options menu](#options-menu), but when setting, it will display in 24h so you can tell AM from PM.
+The time of day can be displayed in either 12h or 24h format per the [options menu](#options-menu), but when setting, it will display in 24h so you can tell AM from PM.
 
-In the [options menu](#options-menu), you can enable automatic daylight saving time adjustment, an hourly chime, and dimming/shutoff of the display at certain times, among other things.
+In the [options menu](#options-menu), you can also enable automatic daylight saving time adjustment, an hourly chime, and dimming/shutoff of the display at certain times, among other things.
 
-### Calendar Mode
+### Calendar
 
-The calendar cycles through several displays, before returning to the Time mode:
+The calendar cycles through several displays, before returning to the time of day:
 
-* **The date.** You can specify its format in the [options menu](#options-menu). When setting, it will ask for year, then month, then date. 
+* **The date.** Several formats are available in the [options menu](#options-menu). When setting, it will ask for year, then month, then date.
 
 * **Day counter.** This will count down to, or up from, a date of your choice, repeating every year. When setting, it will ask for month, then date, then direction (0 = count down, 1 = count up).
 
   * TIP: To display the day of the year, set it to count up from December 31.
 
-* **Sunrise and sunset.** These two displays show the previous and next sunrise or sunset (indicated by `1` or `0` on the seconds tubes). For this to work correctly, set your latitude, longitude, and UTC offset in the [options menu](#options-menu).
+* **Sunrise and sunset.** These two displays show the previous and next sunrise or sunset (indicated by `1` or `0` on the seconds tubes). For this to work correctly, set your latitude, longitude, and UTC offset in the [options menu](#options-menu). They will display in the same 12h/24h format as the time of day.
 
-### Alarm Mode
+### Alarm
 
-The alarm is always shown in 24h format so you can tell AM from PM. Use **Up/Down** to switch the alarm between **on, skip, and off** (indicated by `1`/`01`/`0` on the seconds tubes, and high/medium/low beeps).
+The alarm is always shown in 24h format so you can tell AM from PM. Use **Up/Down** to switch the alarm between **on, skip, and off** (indicated by `1`/`01`/`0` on the seconds tubes, and/or high/medium/low beeps).
 
-When the alarm sounds, press any button to snooze it, or briefly hold any button to silence it for the day (it will give a short beep, and the display will blink once).
+When the alarm sounds, press any button to snooze it, or briefly hold any button to silence it (it will give a short beep, and the display will blink once).
 
-**Skip** will silence the next alarm in advance — useful if you’re taking a day off tomorrow, or you wake up before your alarm. In the [options menu](#options-menu), you can program the alarm to skip automatically during the work week or on weekends – and when this is active, you can also _unskip_ the next alarm by switching it to `1`. If you have an [Alt button](#the-alt-button), you can set it to toggle the skip setting.
+**Skip** will silence the next alarm in advance — useful if you’re taking a day off, or you wake up before your alarm. In the [options menu](#options-menu), you can program the alarm to skip automatically during the work week or on weekends – and when this is active, you can also _unskip_ the next alarm by simply switching it back on. The [Alt button](#the-alt-button) can be set to toggle the skip setting.
 
 In the [options menu](#options-menu), you can set the snooze length and the alarm sound. If your clock has a [relay in switched mode](#hardware-configuration), you can also choose to switch on the relay at alarm time (like a clock radio) instead of sounding the beeper.
 
-### Timer Mode
+### Countdown Timer
 
-This countdown timer can be set up to 18 hours. It begins running as soon as you finish setting it, and will continue to run in the background if you change to a different mode. To cancel the running timer, hold **Select**. When the timer runs out, press any button to silence. If power is lost, the timer will clear.
+The countdown timer can be set up to 18 hours. It begins running as soon as you finish setting it, and will continue to run in the background if you switch to a different display. To cancel the running timer, hold **Select** while the timer is displayed. When the timer runs out, press any button to silence. If power is lost, the timer will clear.
 
 In the [options menu](#options-menu), you can set it to be an interval timer (restarting when it reaches zero), and can also select the timer sound. If your clock has a [relay in switched mode](#hardware-configuration), you can also choose to switch on the relay while the timer is running (like the “sleep” function on a clock radio) instead of sounding the beeper.
 
 ### The Alt Button
 
 If your clock is equipped with an **Alt** button, it will do one of two things (depending on your [hardware configuration](#hardware-configuration)):
 
-* If your clock has a switched relay with soft power switch enabled, the **Alt** button acts as the power switch.
+* If your clock has a switched relay with soft power switch enabled (such as for a radio), the **Alt** button acts as the power switch.
 
-* Otherwise, the **Alt** button works as a mode preset, similar to a preset button in a car radio. While viewing the mode you want quick access to, hold **Alt** until it beeps twice; then you can use **Alt** to jump straight to that mode. It works best for Alarm or Timer.
+* Otherwise, it works as a preset button. While viewing the display you want quick access to (such as the alarm or countdown timer), hold **Alt** until it beeps twice; then you can use **Alt** to jump straight there.
 
-  * TIP: If used with Alarm, the **Alt** button will also toggle the skip setting – so to skip (or unskip) the next alarm, you only need to press the **Alt** button twice: once to display it, and once to change it.
+  * TIP: If used with the alarm, the **Alt** button will also toggle the skip setting – so to skip (or unskip) the next alarm, you only need to press the **Alt** button twice: once to display it, and once to change it.
 
 ### Options Menu
 
@@ -79,7 +79,7 @@ If your clock is equipped with an **Alt** button, it will do one of two things (
 | 4 | Leading zero in hour, date, and month? | 0 = no<br/>1 = yes |
 | 5 | Digit fade | 0–20 (in hundredths of a second) |
 | 6 | Auto DST | Add 1h for daylight saving time between these dates (at 2am):<br/>0 = off<br/>1 = second Sunday in March to first Sunday in November (US/CA)<br/>2 = last Sunday in March to last Sunday in October (UK/EU)<br/>3 = first Sunday in April to last Sunday in October (MX)<br/>4 = last Sunday in September to first Sunday in April (NZ)<br/>5 = first Sunday in October to first Sunday in April (AU)<br/>6 = third Sunday in October to third Sunday in February (BZ)<br/>(If the clock is not powered at the time, it will correct itself when connected to power.) |
-| 7 | LED behavior | 0 = always off<br/>1 = always on<br/>2 = on, but follow night/away shutoff if enabled<br/>3 = off, but on when alarm/timer sounds</br>4 = off, but on with switched relay (if equipped)<br/>(Clocks with LED backlighting only) |
+| 7 | LED behavior | 0 = always off<br/>1 = always on<br/>2 = on, but follow night/away shutoff if enabled<br/>3 = off, but on when alarm/timer sounds</br>4 = off, but on with switched relay (if equipped)<br/>(Clocks with LED lighting only) |
 | 8 | Anti-cathode poisoning | Briefly cycles all digits to prevent [cathode poisoning](http://www.tube-tester.com/sites/nixie/different/cathode%20poisoning/cathode-poisoning.htm)<br/>0 = once a day, either at midnight or when night shutoff starts (if enabled)<br/>1 = at the top of every hour<br/>2 = at the top of every minute<br/>(Will not trigger during night/away shutoff) |
 |  | **Alarm** |  |
 | 10 | Alarm auto-skip | 0 = alarm triggers every day<br/>1 = work week only, skipping weekends (per settings below)<br/>2 = weekend only, skipping work week |
@@ -117,7 +117,7 @@ A number of hardware-related settings are specified in config files, so you can
 These settings include:
 
 * **Number of digits** in the display module. Default is 6; small display adjustments are made for 4-tube clocks.
-* **Which modes** are enabled.
+* **Which functions** are enabled (calendar, alarm, etc).
 * **Which pins** are associated with the inputs (controls) and outputs (displays and signals).
   * If your clock includes LED backlighting (e.g. UNDB v8+), specifying an LED pin will enable the LED-related options in the options menu. LEDs should be connected to a PWM pin.
 * **What type of Up/Down controls** are equipped: pushbuttons (default) or rotary encoder (TBD).
@@ -127,8 +127,8 @@ These settings include:
     * In switched mode (default), the relay will be switched to control an appliance like a radio or lamp. If used with timer, it will switch on while timer is running (like the “sleep” function on a clock radio). If used with alarm, it will switch on when alarm trips and stay on for **relay switch duration** (default 2 hours). In this case, the **Alt** button (if equipped) will shut it off immediately, skipping snooze. This mode also enables the option for the LED backlighting, if equipped, to switch with the relay (great for a radio!).
     * In pulse mode, the relay will be pulsed, like the beeper is, to control an intermittent signaling device like a solenoid or indicator lamp; specify **relay pulse duration** (default 200ms).
 * **Soft alarm switch** enabled: default is yes; it is switched with **Up** (on) and **Down** (off) while viewing the alarm time. Change to no if the signal output/appliance has its own switch on this relay circuit; the software alarm will be permanently on.
-* **Soft power switch** enabled (switched relay only): default is yes; appliance can be toggled on/off with **Alt**. Change to no if the appliance has its own power switch (independent of this relay circuit) or does not need to be manually switched. (If set to no, or not using a switched relay, **Alt** acts as a mode preset, as above.)
-* **Various other durations** for things like scrolling speed, set mode timeouts, short and long button holds, “hold to set faster” thresholds, etc.
+* **Soft power switch** enabled (switched relay only): default is yes; appliance can be toggled on/off with **Alt**. Change to no if the appliance has its own power switch (independent of this relay circuit) or does not need to be manually switched. (If set to no, or not using a switched relay, **Alt** acts as a function preset, as above.)
+* **Various other durations** for things like scrolling speed, set function/display timeouts, short and long button holds, “hold to set faster” thresholds, etc.
 
 You can also set the **defaults for the options menu** (in main code, currently) to better suit the clock’s intended use.