ST10F273Z4 datasheet(178/188 Pages) STMICROELECTRONICS

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Known limitations

ST10F273Z4

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Therefore, to prevent the locking situation from occurring, it is important to make sure that

no task can disable interrupts for a period of time during which 2 injection requests can

occur before a read operation is performed.

Detailed analysis

Channel Injection mode allows to convert a specific analog channel without changing the

current operating mode. It can also be used when the A/D converter is running in continuous

or auto scan mode.

The following main points need to be highlighted:

●

The A/D converter must be in Wait for ADDAT read mode in order for the Channel

Injection mode to operate properly.

●

At the end of the injected conversion the data is available in the alternate result register,

ADDAT2, and a Channel Injection Complete Interrupt request is generated (ADEIR

Flag).

●

If the temporary data register used for ADDAT2 read mode is full, the next conversion

(standard or injected) is suspended. The temporary register then stores the content of

ADDAT (standard conversion) or ADDAT2 (injected conversion).

If the temporary data register used for ADDAT2 read mode is full and a new injection request

occurs, then the new converted value is stored into a temporary data register until the

previous one is read from ADDAT2 register.

To ensure correct operation as soon as ADDAT2 register is read, the last converted value

should be moved from temporary register to ADDAT2 and the ADEINT interrupt should be

generated. This allows the CPU to read the last converted value (see Figure 61).

In real circumstances, as soon as the ADDAT2 register is read, the last converted value is

correctly moved from the temporary register to the ADDAT2, but no ADEINT interrupt

request is sent to the Interrupt controller (see Figure 62). As a consequence the CPU/PEC

does not know that a new converted value is available in the ADDAT2 register. When the

next injection request is issued, the A/D converter fills the temporary register again without

generating any ADEINT interrupt request and the converter is stalled. The A/D converter

stays in the “wait for read ADDAT2 register” condition forever.

ST10F273Z4 Datasheet(PDF) 178 Page - STMicroelectronics