CY2273A
Byte 1: CPU Active/Inactive Register
(1 = Active, 0 = Inactive), Default = Active
Bit
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Pin #
47 (-1,-2, and -4)
1 (-3 only)
N/A
N/A
N/A
40
41
43
44
Description
USBCLK
(Reserved) drive to ‘0’
(Reserved) drive to ‘0’
Not used - drive to ‘0’
CPUCLK3 (Active/Inactive)
CPUCLK2 (Active/Inactive)
CPUCLK1 (Active/Inactive)
CPUCLK0 (Active/Inactive)
Bit 3
Bit 2
Bit 1
Bit 0
12
11
10
8
Bit 4
13
Byte 2: PCI Active/Inactive Register
(1 = Active, 0 = Inactive), Default = Active
Bit
Bit 7
Bit 6
Bit 5
--
7
15
Pin #
Description
(Reserved) drive to ‘0’
PCICLK_F (Active/Inactive)
PCICLK5 (Active/Inactive) (-1,-3 and -4)
AGP1 (Active/Inactive) (-2 only)
PCICLK4 (Active/Inactive) (-1,-3 and -4)
AGP0 (Active/Inactive) (-2 only)
PCICLK3 (Active/Inactive)
PCICLK2 (Active/Inactive)
PCICLK1 (Active/Inactive)
PCICLK0 (Active/Inactive)
Byte 3: SDRAM Active/Inactive Register
(1 = Active, 0 = Inactive), Default = Active
Bit
Pin #
Description
SDRAM7 (Active/Inactive)
SDRAM6 (Active/Inactive)
SDRAM5 (Active/Inactive)
SDRAM4 (Active/Inactive)
SDRAM3 (Active/Inactive)
SDRAM2 (Active/Inactive)
SDRAM1 (Active/Inactive)
SDRAM0 (Active/Inactive)
Bit 7 28
Bit 6 29
Bit 5 31
Bit 4 32
Bit 3 34
Bit 2 35
Bit 1 37
Bit 0 38
Byte 4: SDRAM Active/Inactive Register
(1 = Active, 0 = Inactive), Default = Active
Bit
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Pin #
N/A
N/A
N/A
N/A
17
18
20
21
Description
Not used - drive to ‘0’
Not used - drive to ‘0’
Not used - drive to ‘0’
Not used - drive to ‘0’
SDRAM11
SDRAM10
SDRAM9
SDRAM8
Byte 5: Peripheral Active/Inactive Register
(1 = Active, 0 = Inactive), Default = Active
Bit
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
Pin #
N/A
N/A
N/A
47
N/A
N/A
N/A
2
Description
(Reserved) drive to ‘0’
(Reserved) drive to ‘0’
(Reserved) drive to ‘0’
IOAPIC (Active/Inactive) (-3 only)
(Reserved) drive to ‘0’
(Reserved) drive to ‘0’
(Reserved) drive to ‘0’
REF0 (Active/Inactive)
Byte 6: Reserved, for future use
5
CYPRESS [ CYPRESS SEMICONDUCTOR ]
