Nintendo GAME BOY Programming Manual page 162

Game Boy Programming Manual
d7
04h
* For more information, see Section 3.4, Sound Flag Lists.
Command: SOU_TRN (Code: 09h)
(Data transfer using VRAM)
Function: Sends a sound program and sound data to the APU.
d7
00h
* The 4 Kbytes of SGB RAM data immediately following the command is sent to APU RAM.
The data to be transferred must be prepared prior to the frame preceding issuance of the command.
The transfer ends 6 frames after the command is issued (not counting the frame in which the
command is issued).
The beginning of the data for transfer contains a 16-bit representation of the number of data items
and the transfer destination address, and the end contains an ending code and the starting address
of the program. For more information, see Chapter 7: Super Game Boy Sound.
APU RAM program area: 0400h – 2AFFh/9.75 Kbytes
APU RAM music data area: 2B00h – 4AFFh/8 Kbytes
APU RAM sampling data area: 4DB0h-EEFFh/40.25 Kbytes
Note: When SOU_TRN is used, 5 packets of SOU_TRN initialization should be
sent to the register file. For more information, see Section 5.3,
SOU_TRN Initialization Data.
0 1 0 0 1 0
d0
BGM code
When not used, 00h always written.
d0
0 1
Number of packets: 1h (fixed)
Command code: 09h
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