YMF795 Datasheet, PDF (18/45 Pages) YAMAHA CORPORATION – APL-2 Automobile sound Player-2

YMF795
$33h Clock selection
Default: 0000h
Index b15 b14 b13 b12 b11 b10 b9 b8 b7 b6 b5 b4 b3 b2 b1 b0
$33h
0
0
0
0
00
0
00
0
0
0
0
CLKSEL
This register is used to set the clock frequency inputted through CLK_I pin when making the clock setting in the
preset mode.
A clock with any frequency can be input during the reset period.
(For details of the clock setting, see “On clock frequency setting” (page 24)).
CKSEL [2:0]
Clock frequency (MHz)
0h(*)
2.688
1h
19.200
2h
19.680
3h
19.800
4h
8.400
5h
14.400
6h
27.821
7h
12.600
(*)When clock is set in the programmable mode, set CLKSEL[2:0] to “0h”.
$34h Interrupt control
Default: 0000h
Index b15 b14 b13 b12 b11 b10 b9 b8 b7 b6 b5 b4 b3 b2 b1 b0
$34h 0
0
0
0
00
0
00
0 IRQE
IRQ point
The musical score data is taken into the FIFO which has a capacity for 32 data. As the sounds are reproduced, the data in
FIFO are processed and deleted. And when the amount of data remaining in FIFO becomes less than the setting value of
IRQ point, an interrupt signal is generated. At this point, set “0” to IRQE and then write the subsequent musical score
data into FIFO.
Be sure to write data in excess of the IRQ point. After writing the data, reset IRQE to “1” and wait another interrupt
signal.
IRQ point can be set in 32 ways from 0 (empty) to 31 (1 data vacancy).
IRQE is the interrupt enable bit. “1” indicates Enable.
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