ST72325AR7-Auto datasheet(49/243 Pages) STMICROELECTRONICS

49 / 243 page

Obsolete

Product(s)

- Obsolete

Product(s)

ST72325xxx-Auto

Supply, reset and clock management

Doc ID 13770 Rev 3

49/243

In the case of a drop in voltage, the AVD interrupt acts as an early warning, allowing

software to shut down safely before the LVD resets the microcontroller. See Figure 16.

The interrupt on the rising edge is used to inform the application that the VDD warning state

is over.

If the voltage rise time trv is less than 256 or 4096 CPU cycles (depending on the reset delay

selected by option byte), no AVD interrupt will be generated when VIT+(AVD) is reached.

If trv is greater than 256 or 4096 cycles

●

two AVD interrupts will be received if the AVD interrupt is enabled before the VIT+(AVD)

threshold is reached: the first when the AVDIE bit is set, and the second when the

threshold is reached.

●

only one AVD interrupt will occur if the AVD interrupt is enabled after the VIT+(AVD)

threshold is reached.

Figure 16.

Using the AVD to monitor VDD (AVDS bit = 0)

Monitoring a voltage on the EVD pin

This mode is selected by setting the AVDS bit in the SICSR register.

The AVD circuitry can generate an interrupt when the AVDIE bit of the SICSR register is set.

This interrupt is generated on the rising and falling edges of the comparator output. This

means it is generated when either one of these two events occur:

●

VEVD rises up to VIT+(EVD)

●

VEVD falls down to VIT-(EVD)

The EVD function is illustrated in Figure 17.

For more details, refer to Section 19: Electrical characteristics.

VDD

VIT+(AVD)

VIT-(AVD)

AVDF bit

RESET VALUE

IF AVDIE bit = 1

Vhyst

AVD INTERRUPT

REQUEST

INTERRUPT PROCESS

VIT+(LVD)

VIT-(LVD)

LVD RESET

Early Warning Interrupt

(Power has dropped, MCU not

not yet in reset)

trv VOLTAGE RISE TIME

ST72325AR7-Auto Datasheet(PDF) 49 Page - STMicroelectronics

ST72325AR7-Auto Datasheet(HTML) 49 Page - STMicroelectronics

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 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

Datasheet Descarga

Enlace URL