YMF744B
February 3, 1999
-40-
2-2-3. SB Suspend / Resume
The SB block can read the internal state as to support Suspend and Resume functions. T he internal state
is made up of 268 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). T he registers have the
following functions.
F0h: Scan In/ O ut 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 no t 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 o nly.
“0”: Read/Write not possib le
“1”: Read/ Write possible