RTCK-NUS Details

RTC Details

Does not respond to normal PIF Status commands.
01 03 06	RTC status
	2	device type (LE)	[1000]
	1	status
		80	busy
		02	D Down (program time generation failure--cycle power)
		01	B Down (backup time generation failure)

02 09 07	read RTC
	send:
	1	address
		0	flags
		1	RAM
		2	time
	receive:
	8	data
	1	status

0A 01 08	write RTC
	send:
	1	address
	8	data
	receive:
	1	status

Bank details:
	Control Flags (bank 0)
		02 00 00 00 00 00 00 00	write-protect bank 2: Time
		01 00 00 00 00 00 00 00	write-protect bank 1: RAM
		00 80 00 00 00 00 00 00	Ealarm (enable alarm)
		00 20 00 00 00 00 00 00	alarm (read-only)
		00 04 00 00 00 00 00 00	modify
		00 02 00 00 00 00 00 00	child (set to stop time when reading)
		00 01 00 00 00 00 00 00	adjust (set when changing time to sync timers)
		00 00 00 00 FF 00 00 00	alarm minute
		00 00 00 00 00 FF 00 00	alarm hour
		FC 58 FF FF 00 00 FF FF	RESERVED (read-only)
	RAM (bank 1)
		Eight free bytes.  Set WPB1 in flags to modify.
	Time (bank 2)
		All time values are binary decimals; ie. 0x21 = 21, not 33.
		FF 00 00 00 00 00 00 00	seconds
		00 FF 00 00 00 00 00 00	minutes
		00 00 80 00 00 00 00 00	always set?; may not be the case with all models
		00 00 7F 00 00 00 00 00	hours
		00 00 00 FF 00 00 00 00	day
		00 00 00 00 FF 00 00 00	day of week
		00 00 00 00 00 FF 00 00	month
		00 00 00 00 00 00 FF 00	year
		00 00 00 00 00 00 00 FF	year + (100 * v)

	Initializing:
		Send Status cmd.  If ID not 0100 quit.
		If Status.busy set:
			read Flags to buffer
			if no error or Status.busy set:
				buffer &= ~(Flags.modify | Flags.child)
				Write buffer back to Flags.
		return (Status.DDown | Status.BDown)	# Neither should be set, but only DDown is fatal.

	# In practical application the adjust, child, and modify flags do not need to be toggled for the operation to be successful.
	Set Time:
		Read Flags to buffer.
		If Status clear:
			buffer &= ~Flags.WPB2
			buffer |= Flags.adjust
			Write buffer to Flags.
			If Status.busy set:
				Fill buffer with current time.
				Write buffer to Time.
				If Status.busy set:
					Write back original Flags.

	Get Time:
		Read Flags to buffer.
		If Status clear:
			buffer |= Flags.child
			Write buffer to Flags.
			If Status.busy set:
				Read Time to buffer.
				If Status.busy set:
					buffer &= ~Flags.child
					Write buffer to Flags.

	Set Data:
		Send Status cmd.
		If Status clear:
			buffer &= ~Flags.WPB1
			Write buffer to Flags.
			If Status.busy set:
				Write data to RAM.
				If Status.busy set:
					buffer |= Flags.WPB1
					Write buffer to Flags.

	Get Data:
		Send Status cmd.
		If Status clear:
			Read data from RAM.

	# Note: the 0x80 flag on the hours set on at least some models of RTC prevent the alarm from triggering.
	# Alarm should "sound" at hr:mn, just like an alarm clock.
	Set Alarm:
		Read Flags to buffer.
		Set buffer.AlarmMinute and buffer.AlarmHour
		Write buffer to Flags.

	Get Alarm:
		Read Flags to buffer.
		if buffer & (Flags.Ealarm | Flags.Alarm) == (Flags.Ealarm | Flags.Alarm):
			minutes = buffer.AlarmMinute
			hours = buffer.AlarmHour
			return True
		return False