ata6616 ATMEL Corporation, ata6616 Datasheet - Page 74

• Manufacturer Part Number: ata6616
• Description: Microcontroller With Lin Transceiver, 5v Regulator And Watchdog
• Manufacturer: ATMEL Corporation

4.7.1.3
4.7.1.4
74
ATA6616/ATA6617 [Preliminary]
Power-on Reset
External Reset
A Power-on Reset (POR) pulse is generated by an On-chip detection circuit. The detection level
is defined in
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 4-17. MCU Start-up, RESET Tied to Vcc
Figure 4-18. MCU Start-up, RESET Extended Externally
An External Reset is generated by a low level on the RESET pin. Reset pulses longer than the
minimum pulse width (see
running. Shorter pulses are not guaranteed to generate a reset. When the applied signal
reaches the Reset Threshold Voltage – V
MCU after the Time-out period – t
RSTDISBL fuse, see
INTERNAL
INTERNAL
TIME-OUT
TIME-OUT
RESET
RESET
RESET
V
V
CC
CC
Table 4-83 on page
Table 4-69 on page
V
CCRR
V
CCRR
Table 4-82 on page
V
270. The POR is activated whenever Vcc is below the detection
PORMIN
V
TOUT
V
POT
POR
V
PORMAX
– has expired. The External Reset can be disabled by the
t
TOUT
RST
251.
– on its positive edge, the delay counter starts the
270) will generate a reset, even if the clock is not
DRAFT
V
RST
t
TOUT
9132A–AUTO–10/08