CY28RS400
Pin Description
Pin No.
Name
Type
Description
47,46,43,42,
41,40
CPUT/C[2:0]
O, DIF Differential CPU clock output.
Intel Type-X buffer.
50
PCI0/409_410
I/O, 33 MHz clock output/CPU Frequency table Select
PD Intel Type-5 buffer.
0 = 410 frequency select table
1 = 409 frequency select table.
This has an internal pull-down
37
IREF
REF0/ FSA
REF1/FSB
REF2
I
A precision resistor attached to this pin is connected to the internal current reference.
54
I/O,SE, 14.318 MHz REF clock ouput/ CPU Frequency Select. Intel£ Type-5 buffer.
I/O, SE 14.318 MHz REF clock ouput/ CPU Frequency Select. Intel Type-5 buffer.
O, SE 14.318 MHz REF clock ouput. Intel Type-5 buffer.
53
52
7
SCLK
I,PU SMBus-compatible SCLOCK.This pin has an internal pullup, but is tri-stated in power-down.
I/O, PU SMBus compatible SDATA.This pin has an internal pullup, but is tri-stated in power-down.
8
SDATA
27, 28, 30, 29
SRCST/C[1:0]
O, DIF DifferentialSelectableSerialreferenceclock. IntelType-Xbuffer. Includesoverclock
support through SMBUS
12, 13, 16,
17, 18, 19,
22, 23, 24, 25
,34,33
SRCT/C[5:0]
O, DIF 100 MHz Differential Serial reference clock. Intel Type-X buffer.
10,11
CLKREQ#[0:1]
I, SE, Output Enable control for SRCT/C. Output enable control required by Minicard
PD specification. These pins have an internal pull-down.
0 = Selected SRC outputs are enabled, 1 = Selected SRC outputs are disabled
4
6
USB_48
O, SE 48 MHz clock output. Intel Type-3A buffer.
VTT_PWRGD#/PD
I
3.3V LVTTL input. This pin is a level sensitive strobe used to latch the FS_A, FS_B,
PD FS_C and 409_410 inputs. After asserting VTT_PWRGD# (active low), this pin
becomes a realtime input for asserting power down (active high)
48
CPU_STP#
I, PU 3.3V LVTTL input. This pin is used to gate the CPU outputs. CPU outputs are turned
off two cycles after assertion of this pin
9
FSC
I
3.3V LVTTL input. CPU Clock Frequency Select
3
VDD_48
PWR 3.3V power supply for USB outputs
PWR 3.3V power supply for CPU outputs
PWR 3.3V power supply for PCI outputs
PWR 3.3V power supply for REF outputs
PWR 3.3V power supply for SRC outputs
PWR 3.3V power supply for SRC outputs
PWR 3.3V power supply for SRCS outputs
PWR 3.3V Analog Power for PLLs
GND Ground for USB outputs
45
VDD_CPU
VDD_PCI
VDD_REF
VDD_SRC
VDD_SRC1
VDD_SRCS
VDDA
51
56
14, 21
35
32
39
5
VSS_48
44
VSS_CPU
VSS_PCI
VSS_REF
VSS_SRC
VSS_SRC1
VSS_SRCS
VSSA
GND Ground for CPU outputs
49
GND Ground for PCI outputs
55
GND Ground for REF outputs
15, 20, 26
GND Ground for SRC outputs
36
31
38
1
GND Ground for SRC outputs
GND Ground for SRCS outputs
GND Analog Ground
XIN
I
14.318 MHz Crystal Input
14.318 MHz Crystal Output
2
XOUT
O
Rev 1.0,November 22, 2006
Page 2 of 18
SPECTRALINEAR [ SPECTRALINEAR INC ]
