comparison pru_rtaudio.p @ 100:b697e82ebb25

PRU now checks for McASP underrun and resets if detects it.

 #define MCASP_WFIFOCTL			0x1000
 #define MCASP_WFIFOSTS			0x1004
 #define MCASP_RFIFOCTL			0x1008
 #define MCASP_RFIFOSTS			0x100C
 
+#define MCASP_XSTAT_XUNDRN_BIT          0        // Bit to test if there was an underrun
 #define MCASP_XSTAT_XDATA_BIT           5        // Bit to test for transmit ready
 #define MCASP_RSTAT_RDATA_BIT           5        // Bit to test for receive ready 
 	
 // Constants used for this particular audio setup
 #define MCASP_BASE 	MCASP0_BASE

       // Every 2 channels we send one audio sample; this loop already
       // sends exactly two SPI channels.
       // Wait for McASP XSTAT[XDATA] to set indicating we can write more data
 MCASP_WAIT_XSTAT:
       LBBO r2, reg_mcasp_addr, MCASP_XSTAT, 4
+      QBBS START, r2, MCASP_XSTAT_XUNDRN_BIT // if underrun occurred, reset the PRU
       QBBC MCASP_WAIT_XSTAT, r2, MCASP_XSTAT_XDATA_BIT
 
       MCASP_REG_WRITE_EXT MCASP_XBUF, r7
 	
       // Same idea with ADC: even iterations, load the sample into the low word, odd