Active Errata List • • • • During UART Reception, Clearing REN May Generate Unexpected IT SPI Interface - Transmission on Master Mode SPI Interface - SPI SS pin Limitation on Master/Slave SPI - SPI Slave Responding in a Multislave Configuration When Not Selected by the Master and its SPDAT Register Loaded SPI - SPI Slave Not Responding When Selected and Not Loaded ALE Disabled Toggles During Internal MOVX Timer 2 - Baud Rate Generator - No IT When TF2 is Set by Software Timer 2 - Baud Rate Generator - Long Start Time SPI Slave Mode/Data Corrupted 32 kHz Oscillator for AT83C51IC2/T80C51ID2 Needs External Feed Back Resistor RB8 Lost With JBC on SCON C51 Core – Bad Exit of Power-down in X2 Mode • • • • • • • • Errata History Rev A Lot Number above 00395 1st Prod. Nov 2001 Trouble List 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 Errata Descriptions 1. During UART Reception, Clearing REN May Generate Unexpected IT During UART reception, if the REN bit is cleared between a start bit detection and the end of reception, the UART will not discard the data (RI is set). Workaround 80C51 MCUs AT83C51RB2 AT83C51RC2 AT83C51IC2 AT80C51ID2 AT80C51RD2 Errata Sheet Test REN at the beginning of Interrupt routine just after CLR RI, and run the Interrupt routine code only if REN is set. 2. SPI Interface - Transmission on Master Mode A 9th bit is transmitted by the interface when the clock rate is set on divide by 2 mode and a positive polarity is selected; the SPR2, SPR1, SPR0 bits are cleared (000) and CPOL = 1 on the SPCON register. Workaround Set the clock rate divide by 4 and X2 mode. 3. SPI Interface - SPI SS pin Limitation on Master/Slave The SS pin of the SPI does not return to an I/O when a One-to-One Master/Slave intercommunication is performed. Workaround No 4. SPI - SPI Slave Responding in a Multislave Configuration When Not Selected by the Master and its SPDAT Register Loaded In a multislave configuration, if the master is sending the Sck and the Tx data to all the slaves, and only one slave is selected, the non-selected slaves respond and generate the end of the transmission interruption (SPIF) if their SPDAT registers are loaded before the transmission. Workaround No 4242B–8051–03/08 5. SPI - SPI Slave Not Responding When Selected and Not Loaded SPI Slave does not respond when selected by a Master and no Data is loaded to be transmitted. No Rx data is registered and no SPIF interruption is generated at the end of the Transmission. Workaround No 6. ALE Disabled Toggles During Internal MOVX When ALE is disabled, internal MOVX instruction shows toggle of ALE. Workaround No 7. Timer 2 - Baud Rate Generator - No IT When TF2 is Set by Software When timer 2 is used in baud rate generator mode, setting TF2 by software doesn’t generate an interrupt. Workaround Use timer 1 instead of timer 2 to generate baud rate and interrupt. 8. Timer 2 - Baud Rate Generator - Long Start Time When timer 2 is used as baud rate generator, TH2 is not loaded with RCAP2H at the beginning, then UART is not operational before 10000 machine cycles. Workaround Add the initialisation of TH2 and TL2 in the initialisation of timer 2. 9. SPI Slave Mode/Data Corrupted When SPI macro is configured in slave reception mode, the SPI block does not handle the good data on the SPI bus. Workaround No 10. 32 kHz Oscillator for AT83C51IC2/T80C51ID2 Needs External Feed Back Resistor Internal feed back resistor is not connected, thus to start up, the 32 kHz Oscillator an external resistor is required. Workaround Connect between XTALB1 and XTALB2 a 2 MΩ resistor 11. RB8 Lost With JBC on SCON On C51 when using JBC instruction on any bit of SCON register, if RB8 bit changes from "1" to "0" during JBC the "0" is lost and RB8 keeps "1". Workaround The workaround is to clear RB8. In a polling algorithm you must clear RB8 at the beginning of the code and after each time it goes to "1". Interrupt RB8 must be cleared at the beginning of the code and after each time it goes to "1". 2 4242B–8051–03/08 12. C51 Core – Bad Exit of Power-down in X2 Mode When exiting power-down mode by interrupt while CPU is in X2 mode, it leads to bad execution of the first instruction run when CPU restarts. Workaround Set the CPU in X1 mode directly before entering power-down mode. 3 4242B–8051–03/08 Headquarters International Atmel Corporation 2325 Orchard Parkway San Jose, CA 95131 USA Tel: 1(408) 441-0311 Fax: 1(408) 487-2600 Atmel Asia Room 1219 Chinachem Golden Plaza 77 Mody Road Tsimshatsui East Kowloon Hong Kong Tel: (852) 2721-9778 Fax: (852) 2722-1369 Atmel Europe Le Krebs 8, Rue Jean-Pierre Timbaud BP 309 78054 Saint-Quentin-enYvelines Cedex France Tel: (33) 1-30-60-70-00 Fax: (33) 1-30-60-71-11 Atmel Japan 9F, Tonetsu Shinkawa Bldg. 1-24-8 Shinkawa Chuo-ku, Tokyo 104-0033 Japan Tel: (81) 3-3523-3551 Fax: (81) 3-3523-7581 Technical Support Enter Product Line E-mail Sales Contact www.atmel.com/contacts Product Contact Web Site www.atmel.com Literature Requests www.atmel.com/literature Disclaimer: The information in this document is provided in connection with Atmel products. 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