Bits marked with "" are RAM bits that can contain any value and are read/write-accessible.

RX 8801 SA / JE

8.5.2. Related registers

Address

Function

bit 7

bit 6

bit 5

 

bit 4

bit 3

 

bit 2

 

bit 1

 

bit 0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1

 

MIN

{

40

20

10

8

4

2

1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2

 

HOUR

{

{

20

10

8

4

2

1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

3

 

WEEK

{

6

5

4

3

2

1

0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

4

 

DAY

{

{

20

 

10

8

 

4

 

2

 

1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

8

 

MIN Alarm

AE

40

20

10

8

4

2

1

9

 

HOUR Alarm

AE

20

10

8

4

2

1

A

 

WEEK Alarm

AE

6

5

4

3

2

1

0

 

DAY Alarm

20

10

8

4

2

1

 

 

 

D

 

Extension Register

TEST

WADA

USEL

 

TE

FSEL1

 

FSEL0

 

TSEL1

 

TSEL0

E

 

Flag Register

{

{

UF

 

TF

AF

{

 

VLF

 

VDET

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

F

 

Control Register

CSEL1

CSEL0

UIE

 

TIE

 

 

 

 

 

 

RESET

 

 

AIE

{

{

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1) "o" indicates write-protected bits. A zero is always read from these bits. 2)

Before entering settings for operations, we recommend writing a "0" to the AIE bit to prevent hardware interrupts from occurring inadvertently while entering settings.

When the RESET bit value is "1" alarm interrupt events do not occur.

When the alarm interrupt function is not being used, the Alarm registers (Reg - 8 to A) can be used as a RAM register. In such cases, be sure to write "0" to the AIE bit.

When the AIE bit value is "1" and the Alarm registers (Reg - 8 to A) is being used as a RAM register, /INT may be changed to low level unintentionally.

1) WADA (Week Alarm /Day Alarm) bit

The alarm interrupt function uses either "Day" or "Week" as its target. The WADA bit is used to specify either WEEK or DAY as the target for alarm interrupt events.

WADA

Data

Description

 

0

Sets WEEK as target of alarm function

 

(DAY setting is ignored)

Write/Read

 

 

 

1

Sets DAY as target of alarm function

 

 

(WEEK setting is ignored)

 

 

 

 

 

2) Alarm registers (Reg - 8 to A)

Address

Function

bit 7

bit 6

bit 5

bit 4

bit 3

bit 2

bit 1

bit 0

 

 

 

 

 

 

 

 

 

 

8

MIN Alarm

AE

40

20

10

8

4

2

1

9

HOUR Alarm

AE

20

10

8

4

2

1

A

WEEK Alarm

AE

6

5

4

3

2

1

0

DAY Alarm

20

10

8

4

2

1

 

 

The hour, minute, date or day when an alarm interrupt event will occur is set using this register and the WADA bit.

In the WEEK alarm /Day alarm register (Reg - A), the setting selected via the WADA bit determines whether WEEK alarm data or DAY alarm data will be set. If WEEK has been selected via the WADA bit, multiple days can be set (such as Monday, Wednesday, Friday, Saturday).

When the settings made in the alarm registers and the WADA bit match the current time, the AF bit value is changed to "1". At that time, if the AIE bit value has already been set to "1", the /INT pin goes low.

1) The register that "1" was set to "AE" bit, doesn't compare alarm.(Example) Write 80h (AE = "1") to the WEEK Alarm /DAY Alarm register (Reg - A):

Only the hour and minute settings are used as alarm comparison targets. The week and date settings are not used as alarm comparison targets.

As a result, alarm occurs if only an hour and minute accords with alarm data.

2) If all three AE bit values are "1" the week/date settings are ignored and an alarm interrupt event will occur once per minute.

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ETM26E-03