YMF754 Datasheet, PDF (42/60 Pages) YAMAHA CORPORATION – DS-1E

YMF754
2-2-4. SB IRQ Status
F8h: Interrupt Flag Register
Read Only
Default: 00h
b7
b6
b5
b4
b3
b2
b1
b0
-
-
-
-
-
-
-
SBI
b0................SBI: SB Interrupt Flag
This bit indicates that the SB DSP occurs the interrupt. This bit is read only. Thus, read the SB DSP
read port to clearing the interrupt and this bit. Then, the value of the read port is invalid.
2-3. MPU401
MPU401 block is for transmitting and receiving MIDI data. It is compatible with UART mode of
“MPU401”. Full duplex operation is possible using the 16-byte FIFO for each direction, transmitting and
receiving.
The following shows the MPUBase I/O map for MPU401.
MPUBase
MPUBase + 1h
MPUBase + 1h
(R/W)
(R)
(W)
MIDI Data port
Status Register port
Command Register port
port
D7
D6
D5
D4
D3
D2
D1
D0
+0h
Data
+1h (W)
Command
+1h (R) /DSR
/DRR
-
-
-
-
-
-
June 28, 1999
-42-