<7/19> SMPC User's Manual / 2.5 RTC Command

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SMPC User's Manual / Chapter 2 SMPC Commands

■ 2.5 RTC command

The details of the RTC command are shown in tabular form. How to read the table of each command and notes are as follows. You can also manage the double issuance of commands by using the status flag in all commands.

● SMPC interrupt

Those described as "occurred" generate an SMPC interrupt to SH-2 via the SCU at the end of the command. In addition, interrupts can be enabled / disabled by setting the SCU.

● IREG, OREG

Shows the details of IREG and OREG used in the command.
Command parameters are parameters that are set in IREG before the command is issued.
The result parameter is a parameter that is set in OREG by command execution.
The result parameter OREG31 is set by SMPC at the start of command processing. The command code is output to OREG31. By using with the status flag (SF)

By using with the status flag (SF)

Which command is being executed ( SF = 1 )
Which command ended ( SF = 0 )

Can be judged.

● Execution time

Shows the execution time calculated from the number of steps in the SMPC internal firmware. If it collides with an internal task such as RTC increment, the command execution time will change, so it is described in the range of the minimum value and the maximum value.

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No.1

SETTIME

Time setting

Command code 16H SMPC interrupt cannot occur IREG 0 to 6 ORAG 31 Execution time max = xxx 　　　　　　　　min = 70μsec

Function content

Set the RTC time.

Command parameters

		bit7	bit3
OREG0	20100001H	Year 1000 (BCD)	Year 100th (BCD)
OREG1	20100003H	Year 10th (BCD)	First place in the Christian era (BCD)
OREG2	20100005H	Day of the week (hexadecimal) Note 1	Month (hexadecimal) Note 2
OREG3	20100007H	Day 10 (BCD)	First place in the day (BCD)
OREG4	20100009H	Toki tenth place (BCD)	First place in time (BCD)
OREG5	2010000BH	Tenth place (BCD)	1st place (BCD)
OREG6	2010000DH	Second place (BCD)	First place in seconds (BCD)

Note 1

day of week	Sunday	Monday	Tuesday	Wednesday	Thursday	Friday	Saturday
value	0H	1H	2H	3H	4H	5H	6H

Note 2

Month	January	February	March	April	May	June	July	August	September	October	November	December
value	1H	2H	3H	4H	5H	6H	7H	8H	9H	AH	BH	CH

Result parameters

OREG31	bit7	bit6	bit5	bit4	bit3	bit2	bit1	bit0
2010005FH	0	0	0	1	0	1	1	0

remarks

● The time is initialized to "Friday, December 31, 1993 23:59:59 " at the time of SMPC cold reset, and counting starts.

SMPC cold reset occurs under the following conditions

When the reset switch in the battery box on the back of Sega Saturn is pressed
When the main power is turned on (ON) when the battery is not installed or when it is exhausted
When the battery is inserted while the power is off

● actually non-existent data, 7 or more days of the week, more than 13 of the month, a date that does not correspond to the month (leap year correction correction until 2099), in the case of setting the 24 or more of the time, more than 60 minutes, and seconds, The set value and the subsequent count are undefined.

● If the power is turned off (OFF) while issuing the SET TIME command,

If the internal processing of the SETTIME command can be executed before the power off sequence, all data will be updated.
If the power off sequence is executed first, the data before issuing the command is retained.

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