MAP electronics Cocerto-B Especificações descarregar pdf (Página 14)

Usage Notes and Known Design Exceptions to Functional Specifications

www.ti.com

Advisory Analog Subsystem: Potential Race Condition after Executing Analog Subsystem

Functions AnalogClockEnable() or AnalogClockDisable()

Revision(s) Affected 0, A, B

Details The factory functions AnalogClockEnable() and AnalogClockDisable() are provided for

the purpose of configuring the peripheral clocks of the analog modules. When an analog

clock configuration attempt succeeds, the function returns the value of 0.

Due to configuration latencies between the Control Subsystem and Analog Subsystem,

the desired clock configuration will not be effective immediately after the function returns.

A race condition may be encountered if user software attempts to use a module before

the clock configuration is complete.

Further, the factory function InitAnalogSystemClock() expects that the analog clock

configurations are static during execution. If AnalogClockEnable() or

AnalogClockDisable() is executed immediately before InitAnalogSystemClock(), the

initialization sequence may be corrupted because the analog clock configuration is not

static during execution. For such a scenario, the return value of InitAnalogSystemClock()

will not be 0xA005 as expected. If the initialization sequence is corrupted, the device

may require a reset to recover from the error condition.

The AnalogClockEnable() and AnalogClockDisable() functions support back-to-back

executions so a race condition between calls is not possible when these analog clock

configuration functions are executed immediately after each other.

Workaround(s) After executing one or more calls to AnalogClockEnable() or AnalogClockDisable(), flush

the analog clock configuration sequence by executing the factory function

ReadAnalogClockStatus().

The read operation of ReadAnalogClockStatus() is automatically queued behind pending

analog clock configuration updates so its return from execution can be used to

definitively verify that the desired clock configuration sequence has completed.

For example, the following code will enable the ADC module clocks with

AnalogClockEnable() calls, and it will flush the clock configuration operations with

ReadAnalogClockStatus() before resetting the ADC modules:

while((**AnalogClockEnable)(AnalogConfig1,ADC1_ENABLE));

while((**AnalogClockEnable)(AnalogConfig2,ADC2_ENABLE));

(**ReadAnalogClockStatus)(AnalogConfig2);

Adc1Regs.ADCCTL1.bit.RESET = 1;

Adc2Regs.ADCCTL1.bit.RESET = 1;

F28M35x Concerto™ MCU Silicon Errata SPRZ357J–August 2011–Revised July 2014

Submit Documentation Feedback

1 2 ... 9 10 11 12 13 14 15 16 17 18 19 ... 38 39

Sem comentários

MAP electronics Cocerto-B Especificações Página 14