FOR AUTOMOTIVE 125°C OPERATION 2-WIRE CONVENIENCE TIMER

S-35710 Series

15

2. 2 Read mode

After the timer starts to operate, if write operation is not performed to the wake-up time register, the interrupt signal is

not output from the INT pin. The timer stops at "FFFFFF h". The timer value during timing can be confirmed by

reading the time register. This operation is called "read mode".

In order for the timer to operate again, set the RST

_______

pin from "L" to "H" or perform write operation to the wake-up

time register. Regarding the operation, refer to Figure 14 and Figure 15.

Figure 20 and Figure 21 show the status transition diagram about the handshake time-out operation.

Timing status

INT pin = "H"

Timing stop status

INT pin = "H"

Timing status

INT pin = "H"

Timing stop status

INT pin = "L"

Initial status

Wake-up time register = "0 h"

Timer = "0 h"

INT pin = "H"

Timer reset

Timer = "0 h"

INT pin = "H"

Read mode

Write

Write

Write

Read

Read

Read

Power-on

RST pin = "L"

RST pin = "H"

Count up every

second

RST pin = "L"

RST pin = "L"

RST pin = "L"

Write

Read

Timer = "FFFFFF h"

Timer

= Wake-up time register

Automatic

migration

Count up every

second

Timer reset

Wake-up time register = "0 h"

Timer = "0 h"

INT pin = "L"

Write mode

RST pin = "H"

Read

Write

RST pin = "L"

Remark Write: Wake-up time register write command

Read: Time register read command

Write

Figure 20 Status Transition Diagram of Handshake Time-out (Nch Open-drain Output)