AT89C51AC2

Manufacturer Part NumberAT89C51AC2
ManufacturerAtmel Corporation
AT89C51AC2 datasheets
 

Specifications of AT89C51AC2

Flash (kbytes)32 KbytesMax. Operating Frequency40 MHz
Cpu8051-12CMax I/o Pins34
Uart1Adc Channels8
Adc Resolution (bits)10Adc Speed (ksps)62.5
Sram (kbytes)1.25Eeprom (bytes)2048
Self Program MemoryAPIOperating Voltage (vcc)3.0 to 5.5
Timers4IspUART
WatchdogYes  
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Active T89C51AC2, AT89C51AC2 Errata List
Flash/EEPROM – First Read After Write Disturbed
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 Controller/ADC Idle Mode/Loops In High Priority Interrupt
Flash/EEPROM – First Read After Load Disturbed
C51 Core – Bad Exit of Power-down in X2 Mode
Timer0/1
Extra interrupt
-
Timer1
Mode1 Does Not Generate Baud Rate Generator for UART
EEPROM – Lock-up during ISP write.
A/T89C51AC2 Errata History
Lot Number
Errata List
A00151
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14
A00369
1, 3, 4, 5, 6, 7, 8, 9,10, 11, 12, 13,14
A00367, A00368,
1, 3, 5, 6, 7, 8, 9, 10, 11, 12, 13,14
A00396 to A00529
A00510, all lots from A00588
1, 6, 7, 8, 9, 10, 11, 12, 13,14
A/T89C51AC2 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.
Workaround
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 ris-
ing and falling edges).
Workaround
None.
3. Double IT on External Falling Edge on INT1 or INT0 in X2 Mode
When the CPU is in X2 mode and Timer1 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.
Workaround
The workaround is to clear IEx bit in Interrupt subroutine.
INT1_ISR :
CLR IE1
....
; Interrupt sub routine
80C51 MCUs
AT89C51AC2
T89C51AC2
Errata Sheet

AT89C51AC2 Summary of contents

  • Page 1

    ... Active T89C51AC2, AT89C51AC2 Errata List • Flash/EEPROM – First Read After Write Disturbed • Timer 2 – Baud Rate Generator – When TF2 is Set by Software • Timer 2 – Baud Rate Generator – Long Start Time • UART – RB8 Lost with JBC on SCON Register • ...

  • Page 2

    Movc Instruction on Boot Memory from Boot Memory Does Not Work No Movc instruction is performed when a program running on the boot memory tries to read its own code by the Movc instruction. Workaround None. 5. Power OFF ...

  • Page 3

    A NOP instruction has to be inserted after the load instruction in the application. MOVX @DPTR,A ;Load Column latches NOP ; ADDED INSTRUCTION – Load of the column latch in the bootloader area. 11. C51 Core Bad Exit of ...

  • Page 4

    C Init EEPROM program example: #define SIZE_EEPROM 12 unsigned char code tab_eep[SIZE_EEPROM]={0x11,0x22,0x33,0x44,0x55,0x66,0x77,0x88,0x99,0xAA}; void main (void) { unsigned char xdata * address; unsigned char cpt; address =0x00; for (cpt=0; cpt<SIZE_EEPROM; cpt++) { } } Assembler Init EEPROM program example: SIZE_EEPROM EQU ...

  • Page 5

    Mov Mov Load_eeprom: WAIT_FBUSY: End_loop: 14. Timer1 in Mode 1 Does Not Generate Baud Rate to UART – The timer1, when used as a baud rate generator in mode 1 (16 bits counter) for low baud rates, does not generate ...

  • Page 6

    Active UART Bootloader Errata List • Timer 2 and UART Are Not Stopped • Watchdog and Flash API Starting the Bootloader Execution • Autobaud False Start Bit Detection • Flash API “__api_wr_code_page” with 0 Data in Length Parameter Field UART ...

  • Page 7

    Workaround A ‘Special Sync’ can be used with ‘FLIP’ software. In this case, the open port event and the ‘U’ sent are dissociated. The user must first open his COM port with the ‘con- nect’ button, then reset its hardware ...

  • Page 8

    Flash API “__api_wr_code_page” with 0 Data in Length Parameter Field When the Flash API “__api_wr_code_page” is called with the field nb_data equal 0 then 255 data is written in Flash. Workaround Include a test on nb_data before executed __api_wr_code_page ...

  • Page 9

    ... Atmel products are not suitable for, and shall not be used in, automotive applications. Atmel’s products are not intended, authorized, or warranted for use as compo- nents in applications intended to support or sustain life. © Atmel Corporation 2006 . All rights reserved. Atmel tered trademarks, of Atmel Corporation or its subsidiaries. Other terms and product names may be trademarks of others. Atmel Operations ...