Bugfix, refactor, cleanup

Author: clockspot

README.md

@@ -1,38 +1,30 @@
 # arduino-nixie
 Code for Arduino Nano in [RLB Designs](http://rlb-designs.com/) IN-12/17 clock v5.0
 
-Featuring timekeeping by DS1307 real-time clock and six digits multiplexed 3x2 via two SN74141 driver chips
+Featuring timekeeping by DS3231 real-time clock and six digits multiplexed 3x2 via two SN74141 driver chips
 
 **This is an alternate codebase that is very much in progress!**
 
 ## Instructions
 
-_In these instructions, "Select" is the main pushbutton, and "Adjust" can be either a knob (rotary encoder) or a pair of up/down buttons (hold to set faster). Other variations may apply depending on the options selected in the code._
+_In these instructions, **Select** is the main pushbutton, and **Adjust** can be a pair of up/down buttons (hold to set faster), or a knob (rotary encoder). Other variations may apply depending on the options selected in the code._
 
-**Use Adjust to see each of the clock's functions:** *(Alarm and Timer not yet implemented)*
+Press **Select** to cycle through the clock's functions. Some functions return to Time after a few seconds.
 
-* **Time**
-  * Shows the current time of day. (Choose 12h or 24h format in Setup.)
-  * To set time, hold Select 'til display flashes; use Adjust to set (in 24h format), and push Select to save at the top of minute (seconds will set to :00).
-* **Date**
-  * Shows month, date, and weekday as 0=Sunday, 6=Saturday. (Choose month/date or date/month in Setup.)
-  * To set date, hold Select 'til display flashes; then set year, then month, then date, pushing Select to save each.
-* **Alarm**
-  * Shows alarm time (in 24h format) and whether the alarm is on (1) or off (0).
-  * To turn alarm on or off, press Select.
-  * To set alarm, hold Select 'til display flashes; use Adjust to set (in 24h format), and push Select to save.
-  * When alarm goes off, push Select to snooze, or hold to silence until tomorrow.
-* **Timer**
-  * Shows a countdown timer (or 0min 00sec when idle).
-  * To set timer, hold Select 'til display flashes; set time (in hrs, min, sec); and push Select to start. Hold to cancel.
-  * When timer goes off, push Select to silence.
+To set a function, hold **Select** 'til the display flashes; use **Adjust** to set, and **Select** to save.
 
-**Additional settings are available in the Setup menu.**
+| Function | Notes |
+| --- | --- |
+| **Time** shows the time of day, e.g. `12 34 56` for 12:34:56. | You can choose 12h or 24h format in Options. When setting, it's in 24h format (so you can tell AM from PM) and the seconds will reset to :00 when you save. |
+| **Date** shows the month, date, and weekday. e.g. `_2 _4 _0` for Sunday, February 4th. | The weekday is 0=Sunday, 6=Saturday. You can choose month/date or date/month format in Options. Setting is done in three stages: first year, then month, then date. |
+| **Day counter** shows the number of days until/since a date you specify, e.g. `_1 23 __` for 123 days. | The target date is set the same way as **Date.** |
+| **Thermometer** shows the temperature of the onboard DS3231 chip, e.g. `__ 38 25` for 38.25°C (I think). | This may not be very useful as it tends to read higher than ambient temperature and its tolerance is low. |
+| **Alarm** | _Not yet implemented_ |
+| **Timer** | _Not yet implemented_ |
 
-* To enter **Setup**, hold Select for 3 seconds, until "1" appears on the small tubes, which indicates you are viewing the first option (see below). Its current setting is shown on the big tubes.
-  * Push Select to cycle through options; use Adjust to set; hold Select to exit.
+Additional settings are available in the options menu. To access this, hold **Select** for 3 seconds until the display flashes something like `__ _0 _1`. The right tubes indicate you are viewing option 1, and the left tubes indicate its current setting. Use **Select** to cycle through options; **Adjust** to change the setting; and hold **Select** to exit.
 
-| Option | Possible Settings |
+| Option | Settings |
 | --- | --- |
 | 1. Time format | 1 = 12-hour<br/>2 = 24-hour<br/>(time-of-day display only; setting times is always done in 24h) |
 | 2. Date display | 1 = month/date/weekday<br/>2 = date/month/weekday |
@@ -41,7 +33,7 @@ _In these instructions, "Select" is the main pushbutton, and "Adjust" can be eit
 
 **Setup options not implemented yet**
 
-| Option | Possible Settings |
+| Option | Settings |
 | --- | --- |
 | 5. Transition fade | 0–50 (in hundredths of a second) |
 | 6. Digit cycle (prevents [cathode poisoning](http://www.tube-tester.com/sites/nixie/different/cathode%20poisoning/cathode-poisoning.htm)) | 0 = before midnight and/or before day-off<br/>1 = every hour before :01 minute |