MC51 - T2CON problem

[magixe]

Zde je výčet problému co má  89C51RD2  , já mám ale 89C51ED2 ale ERRATA jsem
nějak nenašel ??


9. 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.

8. 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.

7. Timer2 / Downcounter mode / Double IT with Slow Ext. Clock
When the Timer 2 is in 16-bit autoreload and count down mode with external
clock input, 2 interrupts are generated
successively with low frequency on clock input (typically 10-40 KHz).
Workaround
Reload FFFE into TH2-TL2 in ISR and count down to RCAP-1 (to recover cycle
lost in ISR)
Caution: do not work if initially RCAP = 0x0000

6. UART - RB8 Lost with JBC on SCON Register
Possibility to lose RB8 value, if RB8 changes from 1 to 0 during JBC
instruction on SCON register.
Workaround
Clear RB8 at the beginning of the code and after each time it goes to 1.

5. UART / Reception in modes 1, 2 and 3 / UART False Start Bits Detection
When a false start bit occurs on the UART, some UART internal signals are
not reset. Then when a real start bit
occurs, the sampling is shifted.
Workaround
None.

4. 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
Test REN at the beginning of Interrupt routine just after CLR RI, and to run
the Interrupt routine code only if REN is set.