YMU757B Datasheet, PDF (18/43 Pages) YAMAHA CORPORATION – MA-1C

YMU757B
$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
0
0
0
0
0
0
0
0
0
CLKSEL
This setting sets the clock frequency inputted through the CLK_I terminal.
Be sure to execute this setting before reproducing the melody.
Even if clock of which frequency is being inputted during resetting, it is OK.
(As for the details of the establishment of clock, see on "about establishment of clock frequency".)
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 by 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
0
0
0
0
0
0
IRQE
IRQ point
The musical score data is taken into FIFO which has a capacity for 32 data. As the sounds are reproduced, the data in
FIFO are processed and deleted. When the amount of data remaining in FIFO becomes less than the IRQ point set value,
an interrupt signal is generated. At this point, set "0" for IRQE and write the continuing musical score data into FIFO.
Make sure that the written data exceeds the IRQ point. After writing the data, reset "1" for IRQE and wait until another
interrupt signal is generated.
IRQpoint can set 32 ways from 0 (empty) to 31 (1 data vacancy).
IRQE is enable bit. Set “1” for enable.
$35h Speaker volume control
$36h FM volume control
$37h Ear phone output volume control
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