AT  -  Series DataSheet
T89C51CC01CA-ES  -  Errata Sheet,CAN Microcontrollers  -  Atmel  -  8051

Active Errata List
•Timer 2 – Baud Rate Generator – No IT When TF2 is Set by Software
•Timer 2 – Baud Rate Generator – Long Start Time
•UART – RB8 Lost with JBC on SCON Register
•ADC – Interrupt During Idle Conversion
•CAN – CANCONCH Harmless Corruption
•CAN – Sporadic Errors
•C51 Core – Bad Exit of Power-down in X2 Mode
•Timer0/1 – Extra Interrupt
•Timer1 - Mode 1 Does Not Generate Baud Rate Generator for UART
•EEPROM - Lock-up During ISP write
•Transmission after a 3 bit Intermessage
Errata Description
1.Flash/EEPROM – First Read after Write Disturbed
After a write of more than 32 bytes in the EEPROM and 16 bytes in the user Flash memory, the read of the first byte may be disturbed if it occurs just after the write.
Do not load/write more than 32 bytes at a time for EEPROM memory.
Do not load/write more than 16 bytes at a time for user Flash memory.
Or wait 10 ms before reading the first byte.
2.Buffer Noise
Large bounces and high noise are generated when buffers are switching (both rising and falling edges).
None.
3.Double IT on External Falling Edge on INT1 or INT0 in X2 Mode
When the CPU is in X2 mode and Timer 1 or Timer 0 in X1 mode (CKCON = 0x7F), IEx flag is not cleared by hardware after servicing interrupt. In this case, the CPU executes the ISR a second time.