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2.6.2 Example of Serial Sound Interface operation
When using Serial Sound Interface (SSI), the DMA is recommended for reading and writing data quickly
from the receive buffer to the transmit buffer. A programming example using DMA is shown below Figure
2.6.5 shows an example of Serial Sound Interface transmit timing, and Figure 2.6.6 shows an example of
Serial Sound Interface receive timing.
/***** Serial Sound Interface initialization routine *****************************************************
Serial Sound Interface is initialized by disabling.
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The DMA to use is also initialized.
In this example, one DMA is used for each Serial Sound Interface input and output.
*************************************************************************************************************/
ssi1mr1 = 0x00;
ssi1mr0 = 0x00;
dm0sl = 0x00;
dm0con = 0x00;
dm1sl = 0x00;
dm1con = 0x00;
/***** Setting example **********************************************************************************
Audio transmission can be set before or after audio reception
The DMA to use is set.
DMA0 = audio data transmission and DMA1= audio data reception
*************************************************************************************************************/
dm0ic = 0x06;
dm0sl = 0x0e;
sar0 = (unsigned long)&txb_buffer;
dar0 = (unsigned long)&ssi1txb;
tcr0 = txb_counter;
dm1ic = 0x06;
dm1sl = 0x0a;
sar1 = (unsigned long)&ssi1rxb;
dar1 = (unsigned long)&rxb_buffer;
tcr1 = rxb_counter;
/***** Activation processing routine ********************************************************************
DMA activation. DMA0 can be activated before or after DMA1.
*************************************************************************************************************/
dm0con = 0x18;
dm1con = 0x28;
/*******Serial Sound Interface is stopped at this point.
Serial Sound Interface is enabled and audio data transmission/reception starts.***********/
Rev.2.00 Oct 16, 2006
REJ09B0340-0200
(Continued to the next page.)
page 116 of 354
/* SSI STOP */
/* SSI STOP */
/* DMA0 STOP */
/* DMA0 STOP */
/* DMA1 STOP */
/* DMA1 STOP */
/* DMA completion interrupt enabled */
/* DMA0 factor = SSI 1 transmit */
/* source address: buffer RAM, etc. */
/* destination address: SSI 1 transmit buffer */
/* DMA0 transfer cycle setting */
/* DMA completion interrupt enabled */
/* DMA1 factor = SSI 1 receive */
/* source address: SSI 1 receive */
/* destination address: buffer RAM, etc. */
/* DMA1 transfer cycle setting */
/* DMA0 start [16bit, SRC = inc, single] */
/* DMA1 start [16bit, DES = inc, single] */
2. Serial sound interface
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