YMF724F
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 |
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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
September 21, 1998