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YMF724F
September 21, 1998
-35-
2-2-3. SB Suspend / Resume
The SB block can read the internal state as to support Suspend and Resume functions. The internal state
is made up of 218 flip flops. To read the state, these states are shifted in order and read 8 bits at a time
from the SCAN DATA register.
These registers are mapped to the SB Mixer space (see SB Mixer Register map). The registers have the
following functions.
F0h: Scan In/ Out Control
Read / Write
Default: 00h
b7 b6 b5 b4 b3 b2 b1 b0
SBPDA
- - - SS SM SE
SBPDR
b0................SBPDR: Sound Blaster Power Down Request
This bit stops the internal state of the Sound Blaster block.
“0”: Normal (default)
“1”: Stop
b1................SE: Scan Enable
This bit Shifts the internal state by 1 bit. Setting a “1” followed by a “0” shifts the internal state.
b2................SM: Scan Mode
This bit sets whether to read or write the state.
“0”: Write (default)
“1”: Read
b3................SS: Scan Select
This bit gives permission to read or write the internal data to the SCAN DATA register.
“0”: Normal operation (Do not allow read or write). (default)
“1”: Allow read and write.
b7................SBPDA: Sound Blaster Power Down Acknowledgement
This bit indicates that the SB Block is ready to read or write to the internal state after setting SBPDR.
This bit is read only.
“0”: Read/Write not possible
“1”: Read/ Write possible