ATtiny5 datasheet(28/168 Pages) ATMEL

28 / 168 page

8127C–AVR–10/09

ATtiny4/5/9/10

8.2.1

Power-on Reset

A Power-on Reset (POR) pulse is generated by an on-chip detection circuit. The detection level

is defined in section “System and Reset Characteristics” on page 119. The POR is activated

whenever VCC is below the detection level. The POR circuit can be used to trigger the Start-up

Reset, as well as to detect a failure in supply voltage.

A Power-on Reset (POR) circuit ensures that the device is reset from Power-on. Reaching the

Power-on Reset threshold voltage invokes the delay counter, which determines how long the

device is kept in reset after VCC rise. The reset signal is activated again, without any delay, when

VCC decreases below the detection level.

Figure 8-2.

MCU Start-up, RESET Tied to VCC

Figure 8-3.

MCU Start-up, RESET Extended Externally

8.2.2

VCC Level Monitoring

ATtiny4/5/9/10 have a VCC Level Monitoring (VLM) circuit that compares the voltage level at the

VCC pin against fixed trigger levels. The trigger levels are set with VLM2:0 bits, see “VLMCSR –

VCC Level Monitoring Control and Status register” on page 33.

The VLM circuit provides a status flag, VLMF, that indicates if voltage on the VCC pin is below the

selected trigger level. The flag can be read from VLMCSR, but it is also possible to have an

interrupt generated when the VLMF status flag is set. This interrupt is enabled by the VLMIE bit

in the VLMCSR register. The flag can be cleared by changing the trigger level or by writing it to

zero. The flag is automatically cleared when the voltage at VCC rises back above the selected

trigger level.

RESET

TIME-OUT

INTERNAL

RESET

TOUT

POT

RST

RESET

TIME-OUT

INTERNAL

RESET

TOUT

POT

RST

VCC

ATtiny5 데이터시트(PDF) 28 Page - ATMEL Corporation

ATtiny5 데이터시트(HTML) 28 Page - ATMEL Corporation

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

데이터시트 다운로드

링크 URL