at90ls4433 ATMEL Corporation, at90ls4433 Datasheet - Page 120

• Manufacturer Part Number: at90ls4433
• Description: At90s4433 8-bit Avr Microcontroller With 4k Bytes Of In-system Programmable Flash
• Manufacturer: ATMEL Corporation

120
AT90S/LS4433
3. Brown-out Detection Level
2. Serial Programming at Voltages below 2.9V
1. UART Loses Synchronization if RXD Line is Low when UART Receive is
The Brown-out Detection level can increase when there is heavy I/O-activity on the
device. The increase can be significant when some of the I/O pins are driving heavy
loads.
Problem Fix/Workaround
Select a V
Avoid loading I/O ports with high capacitive or resistive loads.
At voltages below 2.9V, serial programming might fail.
Problem Fix/Workaround
Keep V
Disabled
The UART will detect a UART start bit and start reception even if the UART is not
enabled. If this occurs, the first byte after reenabling the UART will be corrupted.
Problem Fix/Workaround
Make sure that the RX line is high at start-up and when the UART is disabled. An
external RS-232 level converter keeps the line high during start-up.
CC
CC
at 2.9V or higher during In-System Programming.
well above the Brown-out Detection level.
1042H–AVR–04/03