at90ls8535-8mi ATMEL Corporation, at90ls8535-8mi Datasheet - Page 24
at90ls8535-8mi
Manufacturer Part Number
at90ls8535-8mi
Description
8-bit Microcontroller With 8k Bytes In-system Programmable Flash
Manufacturer
ATMEL Corporation
Datasheet
1.AT90LS8535-8MI.pdf
(127 pages)
- Current page: 24 of 127
- Download datasheet (3Mb)
Watchdog Reset
MCU Status Register –
MCUSR
24
AT90S/LS8535
When the Watchdog times out, it will generate a short reset pulse of 1 XTAL cycle dura-
tion. On the falling edge of this pulse, the delay timer starts counting the Time-out period
t
Figure 27. Watchdog Reset during Operation
The MCU Status Register provides information on which reset source caused an MCU
reset.
• Bits 7..2 – Res: Reserved Bits
These bits are reserved bits in the AT90S8535 and always read as zero.
• Bit 1 – EXTRF: External Reset Flag
After a power-on reset, this bit is undefined (X). It can only be set by an External Reset.
A Watchdog Reset will leave this bit unchanged. The bit is cleared by writing a logical
zero to the bit.
• Bit 0 – PORF: Power-on Reset Flag
This bit is only set by a Power-on Reset. A Watchdog Reset or an External Reset will
leave this bit unchanged. The bit is cleared by writing a logical zero to the bit.
To summarize, Table 5 shows the value of these two bits after the three modes of reset.
Table 5. PORF and EXTRF Values after Reset
To make use of these bits to identify a reset condition, the user software should clear
both the PORF and EXTRF bits as early as possible in the program. Checking the
PORF and EXTRF values is done before the bits are cleared. If the bit is cleared before
an External or Watchdog Reset occurs, the source of reset can be found by using Table
6.
TOUT
Bit
$34 ($54)
Read/Write
Initial Value
Reset Source
Power-on Reset
External Reset
Watchdog Reset
. Refer to page 49 for details on operation of the Watchdog.
R
7
–
0
R
6
–
0
R
5
–
0
R
4
–
0
Unchanged
Undefined
EXTRF
1
R
3
–
0
R
2
–
0
EXTRF
See Bit Description
R/W
1
Unchanged
Unchanged
PORF
PORF
R/W
1
0
1041H–11/01
MCUSR
Related parts for at90ls8535-8mi
Image
Part Number
Description
Manufacturer
Datasheet
Request
R
Part Number:
Description:
INTERVAL AND WIPE/WASH WIPER CONTROL IC WITH DELAY
Manufacturer:
ATMEL Corporation
Datasheet:
Part Number:
Description:
Low-Voltage Voice-Switched IC for Hands-Free Operation
Manufacturer:
ATMEL Corporation
Datasheet:
Part Number:
Description:
MONOLITHIC INTEGRATED FEATUREPHONE CIRCUIT
Manufacturer:
ATMEL Corporation
Datasheet:
Part Number:
Description:
AM-FM Receiver IC U4255BM-M
Manufacturer:
ATMEL Corporation
Datasheet:
Part Number:
Description:
Monolithic Integrated Feature Phone Circuit
Manufacturer:
ATMEL Corporation
Datasheet:
Part Number:
Description:
Multistandard Video-IF and Quasi Parallel Sound Processing
Manufacturer:
ATMEL Corporation
Datasheet:
Part Number:
Description:
High-performance EE PLD
Manufacturer:
ATMEL Corporation
Datasheet:
Part Number:
Description:
8-bit Flash Microcontroller
Manufacturer:
ATMEL Corporation
Datasheet:
Part Number:
Description:
2-Wire Serial EEPROM
Manufacturer:
ATMEL Corporation
Datasheet:
Part Number:
Description:
U6046BREAR WINDOW HEATING TIMER / LONG-TERM TIMER
Manufacturer:
ATMEL Corporation
Datasheet: