AT91SAM7S256D-AU Atmel, AT91SAM7S256D-AU Datasheet - Page 64

• Manufacturer Part Number: AT91SAM7S256D-AU
• Description: ARM Microcontrollers - MCU 256K Flash SRAM 64K ARM based MCU
• Manufacturer: Atmel
• Series: SAM7S256r

Specifications of AT91SAM7S256D-AU

• Rohs: yes
• Core: ARM
• Processor Series: AT91SAM
• Data Bus Width: 16 bit/32 bit
• Maximum Clock Frequency: 55 MHz
• Program Memory Size: 256 KB
• Data Ram Size: 64 KB
• On-chip Adc: Yes
• Operating Supply Voltage: 3 V to 3.6 V
• Operating Temperature Range: - 40 C to + 85 C
• Package / Case: LQFP-64
• Mounting Style: SMD/SMT
• Interface Type: 2-Wire, I2S, SPI, USART
• Length: 7 mm

The Watchdog Timer is reset by the proc_nreset signal. As the watchdog fault always causes a processor reset if
WDRSTEN is set, the Watchdog Timer is always reset after a Watchdog Reset, and the Watchdog is enabled by
default and with a period set to a maximum.
When the WDRSTEN in WDT_MR bit is reset, the watchdog fault has no impact on the reset controller.
Figure 13-8. Watchdog Reset
• If WDRPROC is 0, the Processor Reset and the Peripheral Reset are asserted. The NRST line is also asserted,
• If WDRPROC = 1, only the processor reset is asserted.
depending on the programming of the field ERSTL. However, the resulting low level on NRST does not result in
a User Reset state.
WDRPROC = 0
Only if
periph_nreset
proc_nreset
(nrst_out)
RSTTYP
wd_fault
NRST
SLCK
MCK
Freq.
Any
Any
Processor Startup
= 3 cycles
XXX
EXTERNAL RESET LENGTH
8 cycles (ERSTL=2)
0x2 = Watchdog Reset
SAM7S Series [DATASHEET]
6175M–ATARM–26-Oct-12
64