Datasheet

68
4341H–MP3–10/07
AT8xC51SND2C/MP3B
13.6.2 Management
Reading the MP3STA register automatically clears the interrupt flags (acknowledgment) except
the MPANC flags. This implies that register content must be saved and tested, interrupt flag by
interrupt flag to be sure not to forget any interrupts.
Figure 13-6. MP3 Interrupt Service Routine Flow
Note: 1. Test these bits only if needed (unmasked interrupt).
Data Request?
MPFREQ = 1?
Layer Error
Handler
CRC Error
Handler
Data Request
Handler
Ancillary Data
Handler
Synchro Error
Handler
MP3 Decoder
ISR
Read MP3STA
Write MP3 Data
to MP3DAT
Read ANN2:0 Ancillary
Bytes From MP3ANC
Reload MP3 Frame
Through MP3DAT
Load New MP3 Frame
Through MP3DAT
Ancillary Data?
(1)
MPANC = 1?
Sync Error?
(1)
ERRSYN = 1?
Layer Error?
(1)
ERRSYN = 1?