21 I
2
S
21-8
Seiko Epson Corporation
S1C33L26 TECHNICAL MANUAL
• I
2
S FIFO one empty interrupt
When the one empty interrupt is enabled, the I
2
S module generates an interrupt after one stereo data has
been read out from the FIFO. However, the I
2
S module continues shifting out the remaining buffer data un-
til the FIFO becomes absolutely empty.
We suggest filling the FIFO with one group of stereo data (16 bits
×
2 channels (L & R)
×
1) at once in the
one empty interrupt handler.
Note: If the handler fills the FIFO with more than one group of data, it may overwrite the remaining data
in the FIFO. Therefore, the FIFO should always be filled with one group of data in the one empty
interrupt handler.
I2SSTART
I2SBUSY
FIFO
I2S_WS pin
FIFOSTAT[2:0]
I2SFIFOFF
I2SFIFOEF
Interrupt
1, 2, 3, 4
2
2
4
3
1
3
0
1L
1R
2L
2R
3L
3R
4L
4R
5L
5R
6L
6R
Start
2, 3, 4
3, 4
5, 6
4, 5, 6
3, 4, 5, 6
6
Empty
Empty
Half empty interrupt
Write 4 L & R data (1–4)
Write 2 L & R data (5, 6)
I2SSTART
I2SBUSY
FIFO
I2S_WS pin
FIFOSTAT[2:0]
I2SFIFOFF
I2SFIFOEF
Interrupt
1, 2, 3, 4
4
2
3
3
2, 3, 4
3, 4
E
4
5, 6, 7, 8
6, 7, 8
7, 8
Whole empty interrupt
Write 4 L & R data (1–4)
Write 4 L & R data (5, 6, 7, 8)
1L
1R
2L
2R
3L
3R
4L
4R
5L
5R
6L
6R
Start
Write 4 L & R data (1–4)
2
1
0
Empty