AT90S8515-4PC Atmel, AT90S8515-4PC Datasheet - Page 24

• Manufacturer Part Number: AT90S8515-4PC
• Description: IC MCU 8K FLSH 4MHZ LV 40DIP
• Manufacturer: Atmel
• Series: AVR® 90Sr

Specifications of AT90S8515-4PC

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 4MHz
• Connectivity: SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 32
• Program Memory Size: 8KB (4K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 512 x 8
• Ram Size: 512 x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 6 V
• Oscillator Type: Internal
• Operating Temperature: 0°C ~ 70°C
• Package / Case: 40-DIP (0.600", 15.24mm)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Data Converters: -

Power-on Reset
24
AT90S8515
The user can select the start-up time according to typical oscillator start-up. The number
of WDT oscillator cycles used for each time-out is shown in Table 4. The frequency of
the Watchdog Oscillator is voltage-dependent as shown in “Typical Characteristics” on
page 95.
Table 4. Number of Watchdog Oscillator Cycles
A Power-on Reset (POR) circuit ensures that the device is reset from power-on. As
shown in Figure 23, an internal timer clocked from the Watchdog Timer oscillator pre-
vents the MCU from starting until after a certain period after V
on Threshold Voltage (V
FSTRT Fuse bit in the Flash can be programmed to give a shorter start-up time if a
ceramic resonator or any other fast-start oscillator is used to clock the MCU.
If the built-in start-up delay is sufficient, RESET can be connected to V
an external pull-up resistor. By holding the pin low for a period after V
applied, the Power-on Reset period can be extended. Refer to Figure 25 for a timing
example of this.
Figure 24. MCU Start-up, RESET Tied to V
Figure 25. MCU Start-up, RESET Controlled Externally
INTERNAL
INTERNAL
TIME-OUT
TIME-OUT
FSTRT
Programmed
Unprogrammed
RESET
RESET
RESET
RESET
VCC
VCC
V
V
V
Time-out at V
0.28 ms
16.0 ms
POT
POT
RST
POT
t
), regardless of the V
TOUT
CC
= 5V
V
RST
CC
.
t
TOUT
CC
Number of WDT Cycles
256
16K
rise time (see Figure 24). The
CC
has reached the Power-
CC
directly or via
CC
has been
0841G–09/01