
CY28312B-2
Document #: 38-07596 Rev. **
Page 9 of 17
Byte 13: Programmable Frequency Select N–Value Register
Bit
Name
Default
0
0
0
0
0
0
0
0
Description
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
CPU_FSEL_N7
CPU_FSEL_N6
CPU_FSEL_N5
CPU_FSEL_N4
CPU_FSEL_N3
CPU_FSEL_N2
CPU_FSEL_N1
CPU_FSEL_N0
If Prog_Freq_EN is set, W300 will use the values programmed in
CPU_FSEL_N[7:0] and CPU_FSEL_M[6:0] to determine the CPU output
frequency. The new frequency will start to load whenever CPU_FSELM[6:0] is
updated.
The setting of FS_Override bit determines the frequency ratio for CPU,
SDRAM, AGP and SDRAM. When it is cleared, W312 will use the same
frequency ratio stated in the Latched FS[4:0] register. When it is set,
CY28312B-2 will use the frequency ratio stated in the SEL[4:0] register.
CY28312B-2 supports programmable CPU frequency ranging from 50 MHz to
248 MHz.
Byte 14: Programmable Frequency Select N–Value Register
Bit
Name
Default
0
Description
Bit 7
Pro_Freq_EN
Programmable output frequencies enabled
0 = disabled
1 = enabled
If Prog_Freq_EN is set, W300 will use the values programmed in
CPU_FSEL_N[7:0] and CPU_FSEL_M[6:0] to determine the CPU output
frequency. The new frequency will start to load whenever CPU_FSELM[6:0] is
updated.
The setting of FS_Override bit determines the frequency ratio for CPU,
SDRAM, AGP and SDRAM. When it is cleared, CY28312B-2 will use the same
frequency ratio stated in the Latched FS[4:0] register. When it is set,
CY28312B-2 will use the frequency ratio stated in the SEL[4:0] register.
CY28312B-2 supports programmable CPU frequency ranging from 50 MHz to
248 MHz.
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
CPU_FSEL_M6
CPU_FSEL_M5
CPU_FSEL_M4
CPU_FSEL_M3
CPU_FSEL_M2
CPU_FSEL_M1
CPU_FSEL_M0
0
0
0
0
0
0
0
Byte 15: Reserved Register
Bit
Pin#
–
–
–
–
–
–
–
–
Name
Default
0
0
0
0
0
0
1
1
Description
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved. Write with ‘1’
Reserved. Write with ‘1’
Byte 16: Reserved Register
Bit
Pin#
–
–
–
–
–
–
–
Name
Default
0
0
0
0
0
0
0
Description
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved
Reserved