CY28158
Document #: 38-07039 Rev. *B Page 2 of 10
Pin Definitions
Name Pins Description
X1[1] 5 Reference crystal input
X2[1] 6 Reference crystal feedback
CPU [0–5] 41, 42, 45, 46, 49, 50 CPU clock outputs
PCI [1–5] 11, 12, 14, 15, 18 PCI clock outputs, synchronously running at 33.33 MHz
PCI_F 9 Free running PCI clock
3V66 [0–1] 25, 26 3V66 clock outputs, running at 66.66 MHz
IOAPIC [0–2] 53, 54, 55 IOAPIC clock outputs, running at 16.67 MHz
REF [0–1] 2, 3 Reference clock outputs, 14.318 MHz
48MHZ 30 48-MHz USB clock output
CPU_STOP# 36 Active LOW input, disables CPU and 3V66 clocks when asserted
PCI_STOP# 37 Active LOW input, disables PCI clocks when asserted
PWR_DWN# 35 Active LOW input, powers down part when asserted
SPREAD# 34 Active LOW input, enables spread spectrum when asserted
SEL1 33 CPU frequency select input (See Function Table)
SEL0 32 CPU frequency select input (See Function Table)
SEL133/100# 28 CPU frequency select input (See Function Table)
GND_REF 1 3.3V Reference ground
GND_PCI 7, 8, 13, 19 3.3V PCI ground
GND_3V66 20, 21, 24 3.3V 66-MHz (AGP) ground
GND_48MHZ 29 3.3V 48-MHz (USB) ground
GND_IOAPIC 52 2.5V APIC ground
GND_CPU 40, 44, 48 2.5V CPU ground
GNDA 38 Analog ground to PLL and Core
VDD_REF 4 3.3V Reference voltage supply
VDD_PCI 10, 16, 17 3.3V PCI voltage supply
VDD_3V66 22, 23, 27 3.3V 66-MHz (AGP) voltage supply
VDD_48MHZ 31 3.3V 48-MHz (USB) voltage supply
VDD_IOAPIC 56 2.5V APIC voltage supply
VDD_CPU 43, 47, 51 2.5V CPU voltage supply
VDDA 39 Analog voltage supply to PLL and Core
Note:
1. For best accuracy, use a parallel-resonant crystal, CLOAD = 18 pF. For crystals with different CLOAD, please refer to the application note, “Crystal Oscillator
Topics.”