Model 4: The Radio Controlled UTC Clock

Date:2018-11-11

Intro

Design Decisions

• 128 ticks/sec
• uptime counter
• multitasker
• a battery backed real time clock is connected via i2c
• start time is read from RTC
• RTC generates 32768 Hz signal to drive clock ticks
• run epoch seconds as additional software clock
• use epoch seconds to derive times in 3 different time zones, read desired zone from 2 input pins
• conversion to and from epoch seconds: additional .short versions use cached values for some epoch, e.g. 2017
• shift register drives 7-segment digits as display
• new: DCF77 receiver connected and sampled
• new: additional software clock to track DCF77 time
• new: sync: DCF77 time is written to masterclock during startup, after valid telegrams have been received
• new: another sync is requested every hour.

Description

This clock uses the same hardware as Model 3 except for one change: the external DCF77 receiver signal is connected to Pin D.7.

The code below is a complete, working example, tested on an atmega644p controller. The syntax for the includes is such that amforth-shell.py will upload the programm and resolve all #include file directives.

Connecting to DCF77

The additions to the main program are fairly straight forward. We need to define the pin to which the receiver is connected. And while we are at it, we also define an alias name for an led to indicate dcf77 activity.

\ dcf77 RX
: led_dcf  [: led.0 ;] execute ;
PORTD 7 portpin: _dcf

We then need some more functions to control everything.

\ --- DCF77 receiver
Rdefer dcfClock>MasterClock

s" DCF" clock: dcfClock
#include ramtable_to_flash.fs
#include dcf_01.fs

: dcf.resync ( -- )
    \ request update of masterclock from dcf
;

\ copy time from dcfClock to MasterClock
: (dcfClock>MasterClock)
    \ update masterclock from dcfclock
    \ take care of time zones
;

Running dcfClock is hooked into job.tick.

: job.tick
  dcf.tick
;

Updating the counters of MasterClock needs some additional handling at the start of a minute. Please note that dcf.min is not hooked into job.min, because the end of the minute may differ between dcfClock and MasterClock.

: job.min
  f.mc.insync fclr? if
    f.dcf.insync fset? if
      \ dcfClock>MasterClock
      clock>hwclock
      -DD -DRX
      f.mc.insync fset
    then
  then
  _tz.set cd.localtime
  MasterClock min @  #58 = if dcf.resync then ;
;

And not surpisingly, all of this code needs to be activated at startup of the system:

: init
    \ ...
    ['] (dcfClock>MasterClock) to dcfClock>MasterClock
    +dcf
    \ f.dcf.dbg fset \ debug dcf
    \ f.dcf.dbg.rx fset
    f.dcf.commit fset
    led.3 on \ commit pending
    led.2 on \ dcf error unless proven otherwise
    +DD +DRX
;

The Code

\ 2017-09-24  main-30-utc-dcf-wallclock.fs
\
\ Written in 2017 by Erich Wälde <erich.waelde@forth-ev.de>
\
\ To the extent possible under law, the author(s) have dedicated
\ all copyright and related and neighboring rights to this software
\ to the public domain worldwide. This software is distributed
\ without any warranty.
\
\ You should have received a copy of the CC0 Public Domain
\ Dedication along with this software. If not, see
\ <http://creativecommons.org/publicdomain/zero/1.0/>.
\
\ include syntax for upload with amforth-shell.py
\
\     11.059200 MHz main crystal
\     32768 Hz square signal on pin T0
\     timer/counter0
\     128 ticks/second
\
\ minimal clock
\ plus i2c, i2c RTC (ds3231)
\      display: shift registers (TPIC 6B595) and 4 7-segment digits
\      MasterClock in UTC, display in 2 other timezones
\      2 pins for selection of timezone
\ plus
\     stationID, redefined ready-prompt

\ _include builds.frt
#include erase.frt
#include dot-base.frt
\ _include imove.frt
#include bitnames.frt
#include marker.frt
#include environment-q.frt
#include dot-res.frt
#include avr-values.frt
#include is.frt
\ _include dumper.frt
\ _include interrupts.frt
\ these definitions are resolved by amforth-shell.py as needed
\ include atmega644p.fs

#include flags.frt
#include 2variable.frt
#include 2constant.frt
#include 2-fetch.frt
#include 2-store.frt
#include m-star-slash.frt
#include quotations.frt
#include avr-defers.frt
#include defers.frt
#include eallot.frt
#include 2evalue.frt
#include case.frt

marker --start--

$006f Evalue stationID

PORTA $03 bitmask: _tz

\ PORTB 0 portpin: T0
\ PORTB 1 portpin: T1
PORTB 2 portpin: led.0
PORTB 3 portpin: led.1
PORTB 4 portpin: led.2
PORTB 5 portpin: led.3
: led_dcf  [: led.0 ;] execute ;
: led_utc  [: led.1 ;] execute ;
: led_mez  [: led.2 ;] execute ;
: led_mesz [: led.3 ;] execute ;

PORTC 0 portpin: i2c_scl
PORTC 1 portpin: i2c_sda

\ abakus/4x7seg display
PORTD 4 portpin: sr_data
PORTD 5 portpin: sr_clock
PORTD 6 portpin: sr_latch
\ dcf77 RX
PORTD 7 portpin: _dcf

\ --- famous includes and other words
: ms   ( n -- )       0 ?do pause 1ms loop ;
: u0.r ( u n -- )     >r 0 <# r> 0 ?do # loop #> type ;
: odd?  ( x -- t/f )  $0001 and 0= 0= ;
: even? ( x -- t/f )  $0001 and 0= ;

: .stationID_ready
  cr
  [char] ~ emit
  base @  $10 base !  stationID 2 u0.r  base !
  [char] > emit space
;

\ --- driver: status leds
#include leds.fs

\ --- driver: time zone switch
: +sw ( -- )          _tz pin_input ;

\ --- driver: i2c rtc clock
: bcd>dec  ( n.bcd -- n.dec )
  $10 /mod  #10 * + ;
: dec>bcd  ( n.dec -- n.bcd )
  #100 mod  #10 /mod  $10 * + ;

#include i2c-twi-master.frt
#include i2c.frt
#include i2c-detect.frt
: +i2c  ( -- )
  i2c_scl pin_pullup_on
  i2c_sda pin_pullup_on
  i2c.prescaler/1
  #6 \ bit rate --- 400kHz @ 11.0592 MHz
  i2c.init
;

: i2c.scan
  base @ hex
  $79 $7 do
    i i2c.ping? if i 3 .r then
  loop
  base !
  cr
;
$68 constant i2c_addr_rtc
#2000 constant Century
#include i2c_rtc_ds3231.fs

\ --- master clock
#include clocks_v0.3.fs
                                        \ newfangled clock:
                                        \ data as structure
                                        \ sec min hour day month year
                                        \ .date .time .tz
s" UTC" clock: MasterClock
                                        \ create the "master" clock
variable mcFlags
mcFlags  0 flag: f.mc.insync

\ --- timeup
#include timeup_v1.0.fs
                                        \ last_day_of_month ( year month -- last_day )
                                        \ timeup.init
                                        \ timeup
                                        \ tu.upd.limits ( Y m -- )

\ --- uptime
2variable uptime
: ++uptime ( -- )  1. uptime d+! ;
: .uptime  ( -- )  uptime 2@  decimal ud. [char] s emit ;
: du.i     ( d -- )  <# #s #> type ;
: ud.dhms  ( d:T/sec -- )
  2dup decimal du.i [char] s emit space
  &60 ud/mod  &60 ud/mod  &24 ud/mod
  du.i   [char] d emit space    \ days
  2 u0.r [char] : emit          \ hours
  2 u0.r [char] : emit          \ minutes
  2 u0.r                        \ seconds
;
: .uptime.dhms  uptime 2@ ud.dhms ;

\ --- timer0 clock tick
\ 128 ticks/sec
\ timer_0_ overflow
\ clock source pin T0 @ 32768 Hz (from ds3231)
#include clock_tick0_external.fs

                                        \ +ticks
                                        \ tick.over?  ( -- t/f )
                                        \ tick.over!
                                        \ half.second.over?  ( -- 0|1|2 )
: clock.set ( Y m d H M S -- )
  sec ! min ! hour !
  1- day !
  over over
  1- month ! year !
  ( Y m ) tu.upd.limits
;
: clock.get ( -- S M H d m Y )
  sec @ min @ hour @
  day @ 1+ month @ 1+ year @
;
: clock.dot ( S M H d m Y -- )
  #4 u0.r [char] - emit #2 u0.r [char] - emit #2 u0.r  [char] _  emit
  #2 u0.r [char] : emit #2 u0.r [char] : emit #2 u0.r  space .tz
;
: clock.show ( -- )
  clock.get
  clock.dot
;

: .date
  year  @    4 u0.r
  month @ 1+ 2 u0.r
  day   @ 1+ 2 u0.r
;
: .time
  hour @ 2 u0.r [char] : emit
  min  @ 2 u0.r [char] : emit
  sec  @ 2 u0.r
;

: hwclock>clock ( -- )
  rtc.get    \ -- sec min hour wday day month year
     year  !
  1- month !
  1- day   !
  ( wday ) drop
     hour  !
     min   !
     sec   !
  year @   month @ 1+  tu.upd.limits
;
: clock>hwclock ( -- )

  year @   month @ 1+  day @ 1+
  1 \ sunday ":-)
  hour @   min   @     sec @
  ( Y m d wday H M S ) rtc.set
;

#include shiftregister.fs
#include 7seg_1.fs

\ --- epoch seconds, timezones
: u>= ( n n -- t/f ) u< invert ;
: d>s ( d -- n ) drop ;
           variable   _last_epoch
          2variable   _last_esec

#2017        Evalue   EE_last_epoch
#1483228800. 2Evalue  EE_last_esec \ 2017

#include epochseconds.fs
2variable Esec
: ++Esec  ( -- )  1. Esec d+! ;
: .Esec   ( -- )  Esec 2@ ud. ;

2variable EsecOffset
: UTC  ( -- )     0. EsecOffset 2! ;
: MEZ  ( -- )  3600. EsecOffset 2! ;
: MESZ ( -- )  7200. EsecOffset 2! ;
: _tz.set
  _tz pin@
  dup 0 = if
    UTC
    led_utc on  led_mez off led_mesz off
  then
  dup 1 = if
    MEZ
    led_utc off led_mez on  led_mesz off
  then
  dup 2 = if
    MESZ
    led_utc off led_mez off led_mesz on
  then
  dup 3 = if
    UTC
    led_utc on  led_mez off led_mesz off
  then
  drop
;

: local.dt ( -- S M H d m Y )
  Esec 2@  EsecOffset 2@  d+  s>dt.short
;
: cd.localtime
  local.dt          \ -- S M H d m Y
  drop drop drop    \ -- S M H
  rot drop swap     \ -- H M
  >r #10 /mod swap  \ -- H.10 H.1
  r> #10 /mod swap  \ -- H.10 H.1 M.10 M.1
  #4 type.7seg      \ --
;
\ --- DCF77 receiver
Rdefer dcfClock>MasterClock

s" DCF" clock: dcfClock
#include ramtable_to_flash.fs
#include dcf_01.fs

: dcf.resync ( -- )
  f.dcf.insync fclr \ resync dcf time
  f.dcf.commit fset \ sync dcf -> MasterClock wanted
  f.dcf.dbg fset    \ dbg.min on
  f.dcf.dbg.rx fset \ dbg.sec on
;

\ copy time from dcfClock to MasterClock
: (dcfClock>MasterClock)
  dcfClock
  sec  @     min   @     hour @
  day  @ 1+  month @ 1+  year @
  MasterClock
                    \ -- sec min hour day month year
  \ convert "local time" to epoch seconds
  ut>s.short        \ -- T/sec
  \ adjust local time zone
  f.dcf.CEDT fset? if
    #3600. d-
  then
  #3600. d-
  2dup Esec 2! \ copy to Epoch seconds!

  \ convert back to "UTC date time" format
  s>dt.short        \ -- sec min hour day month year

  MasterClock
  year !  1- month !  1- day  !
  hour !  min      !  sec     !

  \ fixme: might cause wreaking havoc?
  dcfClock tick @
  dup MasterClock tick !
  ct.ticks.follow !
;

\ --- multitasker
#include multitask.frt
: +tasks  multi ;
: -tasks  single ;


\ --- timeup jobs ---------------------------
: job.tick
  dcf.tick
;
: job.sec
  ++uptime
  ++Esec
;
: job.min
  f.mc.insync fclr? if
    f.dcf.insync fset? if
      \ dcfClock>MasterClock
      clock>hwclock
      -DD -DRX
      f.mc.insync fset
    then
  then
  _tz.set cd.localtime
  MasterClock min @  #58 = if dcf.resync then ;
;
: job.hour  ;
: job.day   ;
: job.month
  \ update length of month in tu.limits
  MasterClock
  year @  month @ 1+  tu.upd.limits
;
: job.year  ;

create Jobs
  ' job.tick ,
  ' job.sec , ' job.min ,   ' job.hour ,
  ' job.day , ' job.month , ' job.year ,

variable jobCount
: jobCount++
  jobCount @
  6 < if
    1 jobCount +!
  then
;

\ --- task 2 --------------------------------
: run-masterclock
  ['] tx-poll to emit \ add emit to run-masterclock
  begin

    tick.over? if
      tick.over!
      MasterClock
      1 tick +!
      job.tick
    then

    half.second.over?
    dup 0<> if
      dup odd? if       \ half second
        led.1 off
      else              \ second
        led.1 on
        MasterClock
        timeup
        0 tick !
        1 jobCount !
      then
    then
    drop

    \ run one job per loop, not all at once
    jobCount @
    bv tu.flags fset?
    if
      jobCount @ dup
      Jobs + @i execute
      bv tu.flags fclr
    then
    jobCount++

    pause
  again
;
$80 $80 $80 task: task-masterclock \ create task space
: start-masterclock
  task-masterclock tib>tcb
  activate
  \ words after this line are run in new task
  run-masterclock
;
: starttasker
  task-masterclock task-init            \ create TCB in RAM
  start-masterclock                     \ activate tasks job

  onlytask                              \ make cmd loop task-1
  task-masterclock tib>tcb alsotask     \ start task-2
  multi                                 \ activate multitasking
;

\ --- main ----------------------------------
: init
  +sr
  $00 byte>sr $00 byte>sr $00 byte>sr $00 byte>sr
  sr_latch low sr_latch high
  +sw
  +leds leds-intro
  ['] .stationID_ready is .ready

  0. uptime 2!
  0. Esec   2!
  EE_last_epoch _last_epoch  !
  EE_last_esec  _last_esec  2!

  MasterClock
  UTC
  #2017 1 1 0 0 0 clock.set
  timeup.init
  +ticks

  +i2c
  i2c_addr_rtc i2c.ping? if
    hwclock>clock
    clock.get ut>s.short Esec 2!
  else
    _last_epoch @ 1 1 0 0 0 clock.set
    _last_esec 2@ Esec 2!
  then
  _tz.set cd.localtime

  ['] (dcfClock>MasterClock) to dcfClock>MasterClock
  +dcf
  \ f.dcf.dbg fset \ debug dcf
  \ f.dcf.dbg.rx fset
  f.dcf.commit fset
  led.3 on \ commit pending
  led.2 on \ dcf error unless proven otherwise
  +DD +DRX
;
: run
  init
  starttasker
;
: run-turnkey
  applturnkey
  init
  starttasker
;
\ ' run-turnkey to turnkey

: .dcf.diff
  \ 1 \ daylight saving time
  0 \ not daylight saving time
  dcfClock clock.get MasterClock
  dt>s 2dup ud.
  Esec 2@ 2dup ud.
  d- d.
;

: .d ( -- )
  decimal
  .uptime         space space
  clock.show      space
  tick            @ . space
  ct.ticks.follow @ . space space
  .Esec                space
  Esec 2@  EsecOffset  2@ d+
  s>dt.short      clock.dot space
  f.dcf.commit fclr? if .dcf.diff then
  cr
;