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Usage Notes and Known Design Exceptions to Functional Specifications

Advisory Analog Subsystem: Analog Subsystem Function InitAnalogSystemClock() is

Incomplete

Revision(s) Affected 0, A, B

Details The factory function InitAnalogSystemClock() is provided for the purpose of configuring

the clock ratio used by the Analog Subsystem and returning its status. A successful,

properly configured device will return the success code 0xA005.

For affected devices, InitAnalogSystemClock() is missing one step, which may

misconfigure the Analog Subsystem clocking scheme and return a code not equal to

0xA005.

A misconfigured Analog Subsystem clocking scheme may lead to random ACIB faults.

Under such error conditions, all of the following symptoms are exhibited:

1. Reads from the Analog Subsystem return unexpected values. In the vast majority of

cases, the reads return the value of 0x0000.

2. Writes to the Analog Subsystem appear to have no effect.

3. The ACIBERR bit in the NMIFLG registers are set.

4. The CIBSTATUS registers show no error:

• CIBSTATUS[15:8] increments freely

• CIBSTATUS[7:0] = 0x01

5. ACIB activity can be recovered by an ACIB reset initiated by the Master Subsystem.

Workaround(s) Manually complete the clock initialization sequence with an additional step in the user

software immediately prior to calling the InitAnalogSystemClock() function from the

Control Subsystem. This extra step is required for every instance where

InitAnalogSystemClock() is called by user software.

The additional step will assign the value of 7 to the C28x memory space at address

0x4E58. The following code is an example of how the workaround can be implemented

for a device where the desired clock ratio between the Control Subsystem and Analog

Subsystem is 4-to-1:

*(unsigned int*)0x4E58 = 7;

(**InitAnalogSystemClock)(ACLKDIV4);

Once the workaround is in place, InitAnalogSystemClock() should be expected to return

the success code of 0xA005 and no further actions will be necessary for proper ACIB

behavior.

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

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MAP electronics Cocerto-B Spezifikationen Seite 13