SPRZ193T January   2003  – December 2023 SM320F2812 , SM320F2812-EP , SMJ320F2812 , TMS320F2810 , TMS320F2810-Q1 , TMS320F2811 , TMS320F2811-Q1 , TMS320F2812 , TMS320F2812-Q1

 

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  2. 1Introduction
  3. 2Device and Development Tool Support Nomenclature
  4. 3Device Markings
  5. 4Usage Notes and Known Design Exceptions to Functional Specifications
    1. 4.1 Usage Notes
      1. 4.1.1 PIE: Spurious Nested Interrupt After Back-to-Back PIEACK Write and Manual CPU Interrupt Mask Clear Usage Note
  6. 5Known Design Exceptions to Functional Specifications
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  7. 6Documentation Support
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  9. 8Revision History

Advisory

SCI: Bootloader Does Not Clear the ABD Bit Before Auto-Baud Lock

Revision(s) Affected

0, A, B, C, D, E, F and G

Details

The SCI ROM bootloader code does not correctly clear the Auto-Baud Detect (ABD) bit in the SCIFFCT register before the auto-baud process begins. The bootloader code fragment is shown below:


// Prepare for autobaud detection
// Set the CDC bit to enable autobaud detection
// and clear the ABD bit
SCIARegs.SCIFFCT.all = 0x2000;

The comments incorrectly state that the ABD bit is cleared. The ABD bit is cleared by writing a 1 to the ABD_CLR bit (bit 14) of the SCIFFCT register. This situation does not hinder operation from power up or reset because the ABD bit is cleared by default after reset. If, however, the bootloader is invoked a second time from software, then the ABD bit will not be cleared and autobaud lock will not occur properly.

Workaround(s)

If the bootloader is going to be re-invoked by software, the user’s code must first clear the ABD bit before calling the bootloader. To do this, write a 1 to the ABD CLR bit (bit 14) in the SCIFFCT register.