HT95R45 datasheet(47/76 Pages) HOLTEK

47 / 76 page

HT95R45

Rev. 1.00

March 12, 2010

Idle Mode

When the device enters this mode, the normal operating

current, will be reduced to an extremely low standby cur-

rent level. This occurs because when the device enters

the Power Down Mode, both the HCLK and 32768Hz

system oscillators are stopped which reduces the power

consumption to extremely low levels, however, as the

device maintains its present internal condition, it can be

woken up at a later stage and continue running, without

requiring a full reset. This feature is extremely important

in application areas where the microcontroller must

have its power supply constantly maintained to keep the

device in a known condition but where the power supply

capacity is limited such as in battery applications.

Sleep Mode

In the Sleep Mode is similar to the mode, except here

the 32768Hz oscillator continues running after after the

HALT instruction has been executed. This feature en-

ables the device to continue with instruction execution

immediately after wake-up.

Green Mode

In the Green Mode, the 32768Hz oscillator is used as

the system clock for instruction execution. The following

conditions will force the microcontroller enter the Green

Mode:

· Any reset condition from any operational mode

· Any interrupt occurring during the Sleep Mode or Idle

mode

· A Port A Wake-up from the Sleep Mode or Idle Mode

Normal Mode

In the Normal mode the device uses the HCLK gener-

ated by the frequency-up conversion circuit as the sys-

tem clock for instruction execution.

There are four high frequency HCLK system clock se-

lections which are 3.58MHz, 7.16MHz, 10.74MHz and

14.32MHz. When the system is in the Normal Mode

care must be taken when dynamically changing the

HCLK system clock, and for which the following proce-

dure is recommended:

1. Clear bit MODE1 to

²0² to select the Slow Mode

2. Clear UPEN bit to

²0²

3. Program the MODE_1 register bits to select the

required HCLK frequency

4. Set the UPEN bit to

²1²

5. Implement a 20ms software delay to allow the high

frequency clock to stabilise

6. Set the MODE1 bit to

²1² to select the HCLK system

clock

After step 6 above is executed the system clock will be

changed to that defined in the MODE_1 register.

Changing the Operational Mode

Holtek

¢s telephone controllers support two system

clocks and four operational modes. The system clock

can be either 32768Hz or HCLK and the operational

mode can be either Normal, Green, Sleep or Idle mode.

The operation mode is selected using software in the

following way:

· Normal mode to Green mode:

Clear bit MODE1 to

²0², which will change the opera-

tional mode to the Green mode.

The UPEN bit status is not changed. However, the

UPEN bit can be cleared by software.

· Normal mode or Green mode to Sleep mode:

Step 1: Clear bit MODE0 to

²0²

Step 2: Clear bit MODE1 to

²0²

Step 3: Clear bit UPEN to

²0²

Step 4: Execute the HALT instruction

After Step 4, the operational mode will be changed to

the Sleep mode.

· Normal mode or Green mode to Idle Mode:

Step 1: Set bit MODE0 to

²1²

Step 2: Clear bit MODE1 to

²0²

Step 3: Clear bit UPEN to

²0²

Step 4: Execute the HALT instruction

After Step 4, the operational mode will be changed to

the Idle Mode.

· Green Mode to Normal Mode:

Step 1: Set bit UPEN to

²1²

Step 2: Execute a 20ms software delay

Step 3: Set bit MODE1 to

²1²

After Step 3, the operational mode will be changed to

the Normal mode.

· Sleep mode or Idle mode to Green mode:

Method 1: The occurrence of any reset condition

Method 2: Any active interrupt

Method 3: A Port A wake-up

Note that a Timer/Event Counter 0/1 and RTC interrupt

will not be generated when in the Idle mode as the

32768Hz crystal oscillator is stopped.

HT95R45 Datasheet(PDF) 47 Page - Holtek Semiconductor Inc

HT95R45 Datasheet(HTML) 47 Page - Holtek Semiconductor Inc

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76

Datasheet Download

Link URL