Yamaha YMF795 Manual page 18

$33h Clock selection
Default: 0000h
Index b15 b14 b13
$33h 0 0 0
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]
0h(*)
1h
2h
3h
4h
5h
6h
7h
(*)When clock is set in the programmable mode, set CLKSEL[2:0] to "0h".
$34h Interrupt control
Default: 0000h
Index b15 b14 b13
$34h 0 0 0
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.
b12 b11 b10 b9
0 0 0 0
Clock frequency (MHz)
2.688
19.200
19.680
19.800
8.400
14.400
27.821
12.600
b12 b11 b10 b9
0 0 0 0
-18-
b8 b7 b6 b5
0 0 0 0
b8 b7 b6 b5
0 0 0 IRQE
YMF795
b4 b3 b2 b1
0 0 CLKSEL
b4 b3 b2 b1
IRQ point
b0
b0