CY28551 Universal Clock Generator for Intel, VIA, and SIS® Features Compliant to Intel® CK505 Selectable CPU clock buffer type for Intel P4 or K8 selection Selectable CPU frequencies Universal clock to support Intel, SiS and VIA platform 0.7V Differential CPU clock for Intel CPU 3.3V Differential CPU clock for AMD K8 100 MHz differential SRC clocks 96 MHz differential dot clock 133 MHz Link clock 48 MHz USB clock 33 MHz PCI clocks Block Diagram Dynamic Frequency Control Dial-A-Frequency® WatchDog Timer Two Independent Overclocking PLLs Low-voltage frequency select input I2C support with readback capabilities Ideal Lexmark Spread Spectrum profile for maximum electromagnetic interference (EMI) reduction • 3.3V Power supply • 64-pin QFN package CPU SRC SATA PCI REF LINK DOT96 24_48M 48M x2 x8 x1 x7 x3 x2 x1 x1 x1 PCIET [8:1] PCIEC[8:1] DOC[2:1] FS[D:A] VDD_SATA SEL_P4_K8 PCIET0 /SATAT PCIEC0 /SATAC PLL2 PCIEX Divider Multiplexer Controller VDD_DOT DOT96T/SATAT/LINK0 DOT96C/SATAC/LINK1 SEL[1:0] PLL3 SATA VDD_PCI Divider PCI[6:0] XOUT XIN VSSREF REF2/**MODE PCI0/CLKREQ#B **DOC1 PCI1/CLKREQ#A VSSPCI CPUT[1:0] CPUC[1:0] VDD_PCIEX Divider PCI2/**FSA VDD_CPU PC3/*FSB PLL1 CPU PCI5/*SEL0 REF[2:0] PLL Reference VDDPCI 14.318MHz Crystal PCI4/*SELP4_K8 VDD_REF Xin Xout REF1 /**FSC Pin Configuration RESET_I#/ SRESET# REF0/ **FSD • • • • • • • • • • • • • • • • • • 64 63 62 61 60 59 58 57 56 55 54 53 52 51 50 49 PCI6_F 1 VDD48 2 **SEL24_48 / 24_48M 3 **SEL1/48M 4 VSS48 5 VDDDOT 6 LINK0/DOT96T/SATAT 7 LINK1/DOT96C/SATAC 8 VSSDOT 9 VDDSATA 10 SATAT/PCIEXT0 11 SATAC/PCIEXC0 12 VSSSATA 13 PCIEXT1 14 PCIEXC1 15 VSSPCIE 16 48 47 46 45 44 43 42 41 40 39 38 37 36 35 34 33 CY28551 VDDREF SCLK SDATA VTTPWRG#/PD CPUT0 CPUC0 VDDCPU CPUT1 CPUC1 VSSCPU **DOC2 VSSA VDDA PCIEXT8/CPU_STP# PCIEXC8/PCI_STP# VDDPCIE PCIEXT7 PCIEXC7 VSSPCIE PCIEXT6 PCIEXC6 PCIEXT5 PCIEXC5 VDDPCIE PCIEXC4 PCIEXT4 VSSPCIE PCIEXC3 PCIEXT3 VDD_48 48M Divider VDDPCIE PCIEXT2 PLL4 Fixed PCIEXC2 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 TPWR_GD#/PD 24_48M SEL24_48 RESET_I# SDATA SCLK I2C Logic * Indicates internal pull up ** indicates internal pull down WDT Cypress Semiconductor Corporation Document #: 001-05675 Rev. *C SRESET# • 198 Champion Court • San Jose, CA 95134-1709 • 408-943-2600 Revised July 26, 2006 CY28551 Pin Description Pin No. Name Type Description 1 PCI6_F O 2 VDD48 PWR 3 **SEL24_48#/24_4 I/O, PD 3.3V tolerant input for 24 MHz, 48 MHz selection/24_48MHz clock output. Internal 8M 150k pull down 1 = 24 MHz, 0 = 48 MHz Intel Type-3A output buffer 4 **SEL1/48MHz 5 VSS48 GND Ground for outputs 6 VDDDOT PWR 3.3V Power supply for outputs 7,8 LINK0/DOT96T/SA O, Link output for VIA and SIS, differential 96 MHz clock output and 100 MHz differential SE/DiF clock. The output is selected by SEL[1:0] TAT LINK1/DOT96C/SA TAC 9 VSSDOT GND Ground for outputs 10 VDDSATA PWR 3.3V Power supply for outputs 11,12 PCIEX0[T/C]/SATA O, DIF Differential SRC clock output/Differential SATA SRC clock output [T/C] Intel Type-SR output buffer 13 VSSSATA 14,15 PCIEX[T/C]1 16 VSSPCIE 17,18 PCIEX[T/C]2 19 VDDPCIE 20,21 PCIEX[T/C]3 22 VSSPCIE 23,24 PCIEX[T/C]4 25 VDDPCIE 26,27,28,29 PCIEX[T/C][5:6] 30 VSSPCIE 31,32 PCIEX[T/C]7 Free running 33 MHz clock output. Intel Type-3A output buffer 3.3V power supply for outputs. I/O, PD 3.3V tolerant input for output selection/48MHz clock output. Refer to Table 1 for selection options Internal 150k pull down GND Ground for outputs O, DIF 100 MHz Differential serial reference clock. Intel Type-SR output buffer GND Ground for outputs O, DIF 100 MHz Differential serial reference clock. Intel Type-SR output buffer PWR 3.3V power supply for outputs. O, DIF 100 MHz Differential serial reference clock. Intel Type-SR output buffer GND Ground for outputs O, DIF 100 MHz Differential serial reference clock. Intel Type-SR output buffer PWR 3.3V power supply for outputs O, DIF 100 MHz Differential Serial reference clock. Intel Type-SR output buffer GND Ground for outputs O, DIF 100 MHz Differential Serial reference clock. Intel Type-SR output buffer 33 VDDPCIE 34,35 PCIEXT8/CPU_ST I/O, DIF OP# PCIEXC8/PCI_ST OP# 3.3V-tolerant input for stopping PCI and SRC outputs/3.3V-tolerant input for stopping CPU outputs/100-MHz Differential serial reference clocks. The two multifunction pins are selected by MODE. Default PCIEX8 Intel Type-SR output buffer 36 VDDA PWR 3.3V Power supply for PLL. 37 VSSA GND Ground for PLL. 38 **DOC2 I, PD Dynamic Over Clocking pin 0 = normal, 1 = Frequency will be changed depend on DOC register. Internal 150k pull-down. GND Ground for outputs. 39 VSSCPU 40,41 CPU[T/C]1 42 VDDCPU 43, 44 CPU[T/C]0 Document #: 001-05675 Rev. *C PWR 3.3V power supply for outputs O, DIF Differential CPU clock output. Intel Type-SR output buffer. PWR 3.3V Power supply for outputs+ O, DIF Differential CPU clock output. Intel Type-SR output buffer. Page 2 of 30 CY28551 Pin Description (continued) Pin No. 45 Name Type Description VTT_PWRGD#/PD I 3.3V LVTTL input. This pin is a level-sensitive strobe used to latch the HW strapping pin inputs. After asserting VTT_PWRGD# (active LOW), this pin becomes a real-time input for asserting power-down (active HIGH). 46 SDATA I/O 47 SCLK I 48 VDDREF 49 XOUT PWR O SMBus compatible SCLOCK. 3.3V Power supply for outputs 14.318 MHz Crystal Output 50 XIN 51 VSSREF GND 52 REF2 O, SE 14.318 MHz REF clock output. Intel Type-5 output buffer 53 **FSC/REF1 I/O,PD, 3.3V tolerant input for CPU frequency selection/14.318 MHz REF clock output SE Internal 150k pull down Intel Type-5 output buffer Refer to DC Electrical Specifications table for Vil_FS and Vih_FS specifications 54 **FSD/REF0 I/O,PD, 3.3V tolerant input for CPU frequency selection/14.318 MHz REF clock output SE Internal 150k pull down Intel Type-5 output buffer Refer to DC Electrical Specifications table for Vil_FS and Vih_FS specifications 55 RESET_I#/SRESE I/O, OD 3.3V tolerant input for reset all of registers to default setting T# 3.3V LVTTL output for watchdog reset signal 56 **DOC1 57 PCI0/**CLKREQ#B I/O,SE, 33 MHz clock output/Output enable control for PCIEX4; 5 via I2C register PD Default is PCI0 0 = Selected PCIEXs are enabled, 1 = Selected PCIEXs are disabled. Internal 150k pull down Intel Type-3A output buffer 58 PCI1/**CLKREQ#A I/O,SE, 33 MHz clock output/Output enable control for PCIEX6, 7via I2C register. Default is PD PCI1 0 = Selected PCIEXs are enabled, 1 = Selected PCIEXs are disabled. Internal 150k pull down Intel Type-3A output buffer 59 VSSPCI 60 **FSA/PCI2 I/O, PD 3.3V tolerant input for CPU frequency selection/33 MHz clock output. Internal 150k pull down Intel Type-3A output buffer Refer to DC Electrical Specifications table for Vil_FS and Vih_FS specifications 61 *FSB/PCI3 I/O, PU 3.3V tolerant input for CPU frequency selection/33 MHz clock output. Internal 150k pull up Intel Type-3A output buffer Refer to DC Electrical Specifications table for Vil_FS and Vih_FS specifications 62 VDDPCI 63 *SELP4_K8/PCI3 I/O, PU 3.3V tolerant input for CPU clock output buffer type selection/33 MHz clock output. Internal 150k pull up Intel Type-3A output buffer Refer to DC Electrical Specifications table for Vil_FS and Vih_FS specifications 0 = K8 CPU buffer type, 1 = P4 CPU buffer type. 64 *SEL0/PCI5 I/O, PU 3.3V tolerant input for output selection/33 MHz clock output. Refer to Table 1 for selection options. Internal 150k pull up Document #: 001-05675 Rev. *C I SMBus compatible SDATA I, PD GND PWR 14.318 MHz Crystal Input Ground for outputs Dynamic Over Clocking pin 0 = normal; 1 = Frequency will be changed depend on DOC register. Internal 150k pull-down Ground for outputs. 3.3V power supply for outputs. Page 3 of 30 CY28551 Table 1. Frequency Select Table FSD FSC FSB FSA FSEL3 FSEL2 FSEL1 FSEL0 Frequency Table (ROM) CPU0 CPU1 SRC LINK PCI CPU VCO CPU PLL SRC PLL Gear CPU CPU PCIE PCIE PCIE Gear Constant M N VCO M N Constant (G) 0 0 0 0 266.6666667 266.6666667 100 66.6667 33.3333 800 80 60 200 800 30 60 200 0 0 0 1 133.3333333 133.3333333 100 66.6667 33.3333 800 40 60 200 800 30 60 200 0 0 1 0 100 66.6667 33.3333 800 60 60 200 800 30 60 200 0 0 1 1 166.6666667 166.6666667 100 66.6667 33.3333 666.6666667 60 63 175 800 30 60 200 0 1 0 0 333.3333333 333.3333333 100 66.6667 33.3333 666.6666667 120 63 175 800 30 60 200 0 1 0 1 100 100 100 66.6667 33.3333 800 30 60 200 800 30 60 200 0 1 1 0 400 400 100 66.6667 33.3333 800 120 60 200 800 30 60 200 0 1 1 1 200 250 100 66.6667 33.3333 1000 60 60 250 800 30 60 200 1 0 0 0 266.6666667 266.6666667 100 133.3333 33.3333 800 80 60 200 800 30 60 200 1 0 0 1 133.3333333 133.3333333 100 133.3333 33.3333 800 40 60 200 800 30 60 200 1 0 1 0 800 60 60 200 800 30 60 200 1 0 1 1 166.6666667 166.6666667 100 133.3333 33.3333 666.6666667 60 63 175 800 30 60 200 1 1 0 0 333.3333333 333.3333333 100 133.3333 33.3333 666.6666667 120 63 175 800 30 60 200 1 1 0 1 100 100 100 133.3333 33.3333 800 30 60 200 800 30 60 200 1 1 1 0 400 400 100 133.3333 33.3333 800 120 60 200 800 30 60 200 1 1 1 1 200 250 100 133.3333 33.3333 1000 60 60 250 800 30 60 200 200 200 200 200 100 133.3333 33.3333 Frequency Select Pins (FS[D:A]) To achieve host clock frequency selection, apply the appropriate logic levels to FS_A, FS_B, FS_C, and FS_D inputs prior to VTT_PWRGD# assertion (as seen by the clock synthesizer). When VTT_PWRGD# is sampled LOW by the clock chip (indicating processor VTT voltage is stable), the clock chip samples the FS_A, FS_B, FS_C, and FS_D input values. For all logic levels of FS_A, FS_B, FS_C, FS_D, and FS_E, VTT_PWRGD# employs a one-shot functionality, in that once a valid LOW on VTT_PWRGD# has been sampled, all further VTT_PWRGD#, FS_A, FS_B, FS_C, and FS_D transitions will be ignored, except in test mode. Serial Data Interface To enhance the flexibility and function of the clock synthesizer, a two-signal serial interface is provided. Through the Serial Data Interface, various device functions, such as individual clock output buffers, can be individually enabled or disabled. The registers associated with the Serial Data Interface initialize to their default setting upon power-up, and therefore use of this interface is optional. Clock device register changes are normally made upon system initialization, if any are required. The interface cannot be used during system operation for power management functions. Data Protocol The clock driver serial protocol accepts byte write, byte read, block write, and block read operations from the controller. For block write/read operation, the bytes must be accessed in sequential order from lowest to highest byte (most significant bit first) with the ability to stop after any complete byte has been transferred. For byte write and byte read operations, the system controller can access individually indexed bytes. The offset of the indexed byte is encoded in the command code, as described in Table 2. The block write and block read protocol is outlined in Table 3, while Table 4 outlines the corresponding byte write and byte read protocol. The slave receiver address is 11010010 (D2h). Table 2. Command Code Definition Bit 7 (6:0) Description 0 = Block read or block write operation, 1 = Byte read or byte write operation Byte offset for byte read or byte write operation. For block read or block write operations, these bits should be '0000000' Document #: 001-05675 Rev. *C Page 4 of 30 CY28551 Table 3. Block Read and Block Write Protocol Block Write Protocol Bit 1 8:2 Description Start Write 10 18:11 19 27:20 28 36:29 37 45:38 Bit 1 Slave address – 7 bits 9 Block Read Protocol 8:2 Description Start Slave address – 7 bits 9 Write Acknowledge from slave 10 Acknowledge from slave Command Code – 8 bits 18:11 Command Code – 8 bits Acknowledge from slave 19 Acknowledge from slave Byte Count – 8 bits (Skip this step if I2C_EN bit set) 20 Repeat start Acknowledge from slave 27:21 Slave address – 7 bits Data byte 1 – 8 bits 28 Read = 1 Acknowledge from slave 29 Acknowledge from slave Data byte 2 – 8 bits 46 Acknowledge from slave .... Data Byte/Slave Acknowledges .... Data Byte N – 8 bits .... Acknowledge from slave .... Stop 37:30 38 46:39 47 55:48 56 Byte Count from slave – 8 bits Acknowledge Data byte 1 from slave – 8 bits Acknowledge Data byte 2 from slave – 8 bits Acknowledge .... Data bytes from slave/Acknowledge .... Data Byte N from slave – 8 bits .... NOT Acknowledge .... Stop Table 4. Byte Read and Byte Write Protocol Byte Write Protocol Bit 1 8:2 Description Start Slave address – 7 bits Byte Read Protocol Bit 1 8:2 Slave address – 7 bits 9 Write 10 Acknowledge from slave 10 Acknowledge from slave 18:11 Command Code – 8 bits 18:11 Command Code – 8 bits Acknowledge from slave 19 Acknowledge from slave Data byte – 8 bits 20 Repeated start 19 27:20 28 Acknowledge from slave 29 Stop Document #: 001-05675 Rev. *C 9 Description Start 27:21 Write Slave address – 7 bits 28 Read 29 Acknowledge from slave 37:30 Data from slave – 8 bits 38 NOT Acknowledge 39 Stop Page 5 of 30 CY28551 Control Registers Byte 0: Control Register 0 Bit @Pup Type Name Description 7 1 R/W PCIEX[T/C]7 PCIEX[T/C]7 Output Enable 0 = Disable (Tri-state), 1 = Enable 6 1 R/W PCIEX[T/C]6 PCIEX[T/C]6 Output Enable 0 = Disable (Tri-state), 1 = Enable 5 1 R/W PCIEX[T/C]5 PCIEX[T/C]5 Output Enable 0 = Disable (Tri-state), 1 = Enable 4 1 R/W PCIEX[T/C]4 PCIEX[T/C]4 Output Enable 0 = Disable (Tri-state), 1 = Enable 3 1 R/W PCIEX[T/C]3 PCIEX[T/C]3 Output Enable 0 = Disable (Tri-state), 1 = Enable 2 1 R/W PCIEX[T/C]2 PCIEX[T/C]2 Output Enable 0 = Disable (Tri-state), 1 = Enable 1 1 R/W PCIEX[T/C]1 PCIEX[T/C]1 Output Enable 0 = Disable (Tri-state), 1 = Enable 0 1 R/W SATA/PCIEX[T/C]0 SATA/PCIEX[T/C]0 Output Enable 0 = Disable (Tri-state), 1 = Enable Byte 1: Control Register 1 Bit @Pup Type Name Description 7 1 R/W SATA/DOT96] 6 1 R/W 24_48M 24_48M Output Enable 0 = Disable, 1 = Enable 5 1 R/W 48M 48M Output Enable 0 = Disable, 1 = Enable 4 1 R/W REF2 REF2 Output Enable 0 = Disable, 1 = Enable 3 1 R/W REF1 REF1 Output Enable 0 = Disable, 1 = Enable 2 1 R/W REF0 REF0 Output Enable 0 = Disable, 1 = Enable 1 1 R/W CPU[T/C]1 CPU[T/C]1 Output Enable 0 = Disable (Tri-state), 1 = Enable 0 1 R/W CPU[T/C]0 CPU[T/C]0 Output Enable 0 = Disable (Tri-state), 1 = Enable SATA/DOT96Output Enable 0 = Disable (Tri-state), 1 = Enable Byte 2: Control Register 2 Bit @Pup Type Name 7 1 R/W Reserved 6 1 R/W PCI6_F PCI6_F Output Enable 0 = Disable, 1 = Enable 5 1 R/W PCI5 PCI5 Output Enable 0 = Disable, 1 = Enable 4 1 R/W PCI4 PCI4 Output Enable 0 = Disable, 1 = Enable Document #: 001-05675 Rev. *C Description Reserved Page 6 of 30 CY28551 Byte 2: Control Register 2 (continued) Bit @Pup Type Name Description 3 1 R/W PCI3 PCI3 Output Enable 0 = Disable, 1 = Enable 2 1 R/W PCI2 PCI2 Output Enable 0 = Disable, 1 = Enable 1 1 R/W PCI1 PCI1 Output Enable 0 = Disable, 1 = Enable 0 1 R/W PCI0 PCI0 Output Enable 0 = Disable, 1 = Enable Byte 3: Control Register 3 Bit @Pup Type Name 7 1 R/W LINK1 LINK1 Output Enable 0 = Disable, 1 = Enable Description 6 1 R/W LINK0 LINKI0 Output Enable 0 = Disable, 1 = Enable 5 1 R/W PCIEX[T/C]8 4 1 R/W Reserved Reserved 3 0 R/W Reserved Reserved 2 1 R/W PCI 33 MHz Output Drive Strength 0 = 2x, 1 = 1x 1 1 R/W REF REF Output Drive Strength 0 = 2x, 1 = 1x 0 0 R/W 48M, 24_48M PCIEX[T/C]8 Output Enable 0 = Disable (Tri-state), 1 = Enable 48 MHz and 24_48M Output Drive Strength 0 = 2x, 1 = 1x Byte 4: Control Register 4 Bit @Pup Type Name 7 0 R/W CPU1 Allow control of CPU1 with assertion of CPU_STP# 0 = Free Running 1 = Stopped with CPU_STP# 6 0 R/W CPU0 Allow control of CPU0 with assertion of CPU_STP# 0 = Free Running 1 = Stopped with CPU_STP# 5 0 R/W PCI6_F Allow control of PCI6_F with assertion of PCI_STP# 0 = Free Running 1 = Stopped with PCI_STP# 4 0 R/W PCIEX Allow control of PCIEX with assertion of PCI_STP# 0 = Free Running 1 = Stopped with PCI_STP# 3 0 R/W FSEL_D 2 0 R/W FSEL_C 1 0 R/W FSEL_B 0 0 R/W FSEL_A Document #: 001-05675 Rev. *C Description SW Frequency selection bits. See Table 1. Page 7 of 30 CY28551 Byte 5: Control Register 5 Bit @Pup Type Name 7 0 R/W CPU_SS1 Description 6 0 R/W CPU_SS0 5 0 R/W CPU_SS_OFF 4 0 R/W PCIE_SS0 3 0 R/W PCIE_SS_OFF PLL2 (PCIEPLL) Spread Spectrum Enable 0 = SRC spread off, 1 = SRC spread on 2 0 R/W SATA_SS_OFF PLL3 (SATAPLL) Spread Spectrum Enable 0 = Spread off, 1 = Spread on 1 HW R/W SEL24_48 24M/48 MHz output selection 0 = 48 MHz, 1 = 24 MHz 0 1 R/W Reserved Reserved CPU (PLL1) Spread Spectrum Selection 00: –0.5% (peak to peak) 01: ±0.25% (peak to peak) 10: –1.0% (peak to peak) 11: ±0.5% (peak to peak) PLL1 (CPUPLL) Spread Spectrum Enable 0 = Spread off, 1 = Spread on PLL2 (PCIEPLL) Spread Spectrum Selection 0: –0.5% (peak to peak) 0: –1.0% (peak to peak) Byte 6: Control Register 6 Bit @Pup Type Name Description 7 0 R/W SW_RESET Software Reset. When set, the device asserts a reset signal on SRESET# upon completion of the block/word/byte write that set it. After asserting and deasserting the SRESET# this bit will self clear (set to 0). 6 0 R/W Reserved 5 0 R/W FIX_LINK_PCI 4 HW R FSD FSD Reflects the value of the FSD pin sampled on power up. 0 = FSD was low during VTT_PWRGD# assertion. 3 HW R FSC FSC Reflects the value of the FSC pin sampled on power up. 0 = FSC was low during VTT_PWRGD# assertion. 2 HW R FSB FSB Reflects the value of the FSB pin sampled on power up. 0 = FSB was LOW during VTT_PWRGD# assertion 1 HW R FSA FSA Reflects the value of the FSA pin sampled on power up. 0 = FSA was LOW during VTT_PWRGD# assertion 0 HW R POWERGOOD Name Reserved LINK and PCI clock source selection 0 = PLL2(SRCPLL), 1 = PLL (SATAPLL) Power Status bit: 0 = Internal power or Internal resets are NOT valid 1 = Internal power and Internal resets are valid Read only Bit 7 sets to 0 when Bit 7 = 0 Byte 7: Vendor ID Bit @Pup Type 7 0 R Revision Code Bit 3 Revision Code Bit 3 6 0 R Revision Code Bit 2 Revision Code Bit 2 5 1 R Revision Code Bit 1 Revision Code Bit 1 4 0 R Revision Code Bit 0 Revision Code Bit 0 3 1 R Vendor ID Bit 3 Vendor ID Bit 3 2 0 R Vendor ID Bit 2 Vendor ID Bit 2 Document #: 001-05675 Rev. *C Description Page 8 of 30 CY28551 Byte 7: Vendor ID (continued) Bit @Pup Type Name Description 1 0 R Vendor ID Bit 1 Vendor ID Bit 1 0 0 R Vendor ID Bit 0 Vendor ID Bit 0 Byte 8: Control Register 8 Bit @Pup Type Name 7 0 R/W CR1_PCIEX7 PCIEX[T/C75 CLKREQ#A Control 1 = PCIEX [T/C]5 stoppable by CLKREQ#B pin 0 = Free running Description 6 0 R/W CR1_PCIEX6 PCIEX[T/C]6 CLKREQ#A Control 1 = PCIEX [T/C]4 stoppable by CLKREQ#B pin 0 = Free running 5 0 R/W CR1_PCIEX5 PCIEX[T/C]5 CLKREQ#B Control 1 = PCIEX [T/C]5 stoppable by CLKREQ#B pin 0 = Free running 4 0 R/W CR1_PCIEX4 PCIEX[T/C]4 CLKREQ#B Control 1 = PCIEX [T/C]4 stoppable by CLKREQ#B pin 0 = Free running 3 0 R/W RESERVED RESERVED, Set = 0 2 0 R/W RESERVED RESERVED, Set = 0 1 0 R/W RESERVED RESERVED, Set = 0 0 0 R/W RESERVED RESERVED, Set = 0 Byte 9: Control Register 9 Bit @Pup Type Name 7 0 R/W DF3_N8 The DF3_N[8:0] configures CPU frequency for Dynamic Frequency. DOC[1:2] =11 6 0 R/W DF2_N8 The DF2_N[8:0] configures CPU frequency for Dynamic Frequency. DOC[1:2] =10 5 0 R/W DF1_N8 The DF1_N[8:0] configures CPU frequency for Dynamic Frequency. DOC[1:2] =01 4 0 R/W RESERVED 3 0 R/W RESERVED 2 1 R/W SMSW_Bypass 1 0 R/W SMSW_SEL Smooth switch select 0 = Select CPU_PLL 1 = Select SRC_PLL 0 0 R/W RESERVED RESERVED, Set = 0 Document #: 001-05675 Rev. *C Description RESERVED, Set = 0 RESERVED, Set = 0 Smooth switch Bypass 0 = Activate SMSW block 1 = Bypass and deactivate SMSW block. Page 9 of 30 CY28551 Byte 10: Control Register 10 Bit @Pup Type Name 7 0 R/W DF1_N7 6 0 R/W DF1_N6 5 0 R/W DF1_N5 4 0 R/W DF1_N4 3 0 R/W DF1_N3 2 0 R/W DF1_N2 1 0 R/W DF1_N1 0 0 R/W DF1_N0 Description The DF1_N[8:0] configures CPU frequency for Dynamic Frequency. DOC[1:2] =01. Byte 11: Control Register 11 Bit @Pup Type Name 7 0 R/W DF2_N7 6 0 R/W DF2_N6 5 0 R/W DF2_N5 4 0 R/W DF2_N4 3 0 R/W DF2_N3 2 0 R/W DF2_N2 1 0 R/W DF2_N1 0 0 R/W DF2_N0 Description The DF2_N[8:0] configures CPU frequency for Dynamic Frequency. DOC[1:2] =10 Byte 12: Control Register 12 Bit @Pup Type Name 7 0 R/W DF3_N7 6 0 R/W DF3_N6 5 0 R/W DF3_N5 4 0 R/W DF3_N4 3 0 R/W DF3_N3 2 0 R/W DF3_N2 1 0 R/W DF3_N1 0 0 R/W DF3_N0 Description The DF3_N[8:0] configures CPU frequency for Dynamic Frequency. DOC[1:2] =11 Byte 13: Control Register 13 Bit @Pup Type 7 0 R/W 6 0 R/W Name Description Recovery_Frequency This bit allows selection of the frequency setting to which the clock will be restored once the system is rebooted 0 = Use HW settings 1 = Recovery N[8:0] Document #: 001-05675 Rev. *C Timer_SEL Timer_SEL selects the WD reset function at SRESET pin when WD times out. 0 = Reset and Reload Recovery_Frequency 1 = Only Reset Page 10 of 30 CY28551 Byte 13: Control Register 13 Bit @Pup Type Name Description 5 1 R/W Time_Scale Time_Scale allows selection of WD time scale 0 = 294 ms, 1 = 2.34 s 4 0 R/W WD_Alarm WD_Alarm is set to ‘1’ when the watchdog times out. It is reset to ‘0’ when the system clears the WD_TIMER time stamp 3 0 R/W WD_TIMER2 2 0 R/W WD_TIMER1 1 0 R/W WD_TIMER0 0 0 R/W WD_EN Watchdog timer time stamp selection 000: Reserved (test mode) 001: 1 * Time_Scale 010: 2 * Time_Scale 011: 3 * Time_Scale 100: 4 * Time_Scale 101: 5 * Time_Scale 110: 6 * Time_Scale 111: 7 * Time_Scale Watchdog timer enable. When the bit is asserted, Watchdog timer is triggered and time stamp of WD_Timer is loaded 0 = Disable, 1 = Enable Byte 14: Control Register 14 Bit @Pup Type Name Description 7 0 R/W CPU_DAF_N7 6 0 R/W CPU_DAF_N6 5 0 R/W CPU_DAF_N5 4 0 R/W CPU_DAF_N4 3 0 R/W CPU_DAF_N3 If Prog_CPU_EN is set, the values programmed in CPU_DAF_N[8:0] and CPU_DAF_M[6:0] will be used to determine the CPU output frequency. The setting of the FS_Override bit determines the frequency ratio for CPU and other output clocks. When it is cleared, the same frequency ratio stated in the Latched FS[E:A] register will be used. When it is set, the frequency ratio stated in the FSEL[3:0] register will be used 2 0 R/W CPU_DAF_N2 1 0 R/W CPU_DAF_N1 0 0 R/W CPU_DAF_N0 Byte 15: Control Register 15 Bit @Pup Type Name Description 7 0 R/W CPU_DAF_N8 6 0 R/W CPU_DAF_M6 5 0 R/W CPU_DAF_M5 4 0 R/W CPU_DAF_M4 3 0 R/W CPU_DAF_M3 If Prog_CPU_EN is set, the values programmed in CPU_DAF_N[8:0] and CPU_DAF_M[6:0] will be used to determine the CPU output frequency. The setting of the FS_Override bit determines the frequency ratio for CPU and other output clocks. When it is cleared, the same frequency ratio stated in the Latched FS[E:A] register will be used. When it is set, the frequency ratio stated in the FSEL[3:0] register will be used. 2 0 R/W CPU_DAF_M2 1 0 R/W CPU_DAF_M1 0 0 R/W CPU_DAF_M0 Document #: 001-05675 Rev. *C Page 11 of 30 CY28551 Byte 16: Control Register 16 Bit @Pup Type Name 7 0 R/W PCIE_DAF_N7 6 0 R/W PCIE_DAF_N6 5 0 R/W PCIE_DAF_N5 4 0 R/W PCIE_DAF_N4 3 0 R/W PCIE_DAF_N3 2 0 R/W PCIE_DAF_N2 1 0 R/W PCIE_DAF_N1 0 0 R/W PCIE_DAF_N0 Description The PCIE_DAF_N[8:0] configures the PCIE frequency for Dial-A-Frequency Byte 17: Control Register 17 Bit @Pup Type Name Description 7 0 R/W Recovery N7 Watchdog Recovery Bit 6 0 R/W Recovery N6 Watchdog Recovery Bit 5 0 R/W Recovery N5 Watchdog Recovery Bit 4 0 R/W Recovery N4 Watchdog Recovery Bit 3 0 R/W Recovery N3 Watchdog Recovery Bit 2 0 R/W Recovery N2 Watchdog Recovery Bit 1 0 R/W Recovery N1 Watchdog Recovery Bit 0 0 R/W Recovery N0 Watchdog Recovery Bit Byte 18: Control Register 18 Bit @Pup Type Name Description 7 0 R/W PCIE_N8 6 0 R/W FS[D:A] FS_Override 0 = Select operating frequency by FS(D:A) input pins 1 = Select operating frequency by FSEL_(3:0) settings 5 0 R/W DF_EN Dynamic Frequency for CPU Frequency Enable 0 = Disable, 1 = Enable 4 0 R/W RESET_I_EN 3 0 R/W Prog_PCIE_EN Programmable SRC Frequency Enable 0 = Disable, 1 = Enabled 2 0 R/W Prog_CPU_EN Programmable CPU Frequency Enable 0 = Disable, 1 = Enable 1 0 R/W Watchdog Autorecovery Watchdog Autorecovery Mode 0 = Disable (Manual), 1= Enable (Auto) 0 0 R/W Recovery N8 Watchdog Recovery Bit PCI-E Dial-A-Frequency Bit N8 RESET_I# Enable 0 = Disable, 1 = Enable Table 5. Crystal Recommendations Frequency (Fund) Cut Loading Load Cap Drive (max.) Shunt Cap (max.) Motional (max.) Tolerance (max.) Stability (max.) Aging (max.) 14.31818 MHz AT Parallel 0.1 mW 5 pF 0.016 pF 35 ppm 30 ppm 5 ppm Document #: 001-05675 Rev. *C 20 pF Page 12 of 30 CY28551 Crystal Recommendations Figure 2. Crystal Loading Example The CY28551 requires a parallel resonance crystal. Substituting a series resonance crystal will cause the CY28551 to operate at the wrong frequency and violate the ppm specification. For most applications there is a 300-ppm frequency shift between series and parallel crystals due to incorrect loading. C lock C hip Ci2 C i1 Pin 3 to 6p Crystal Loading Crystal loading plays a critical role in achieving low ppm performance. To realize low ppm performance, the total capacitance the crystal will see must be considered to calculate the appropriate capacitive loading (CL). Figure 1 shows a typical crystal configuration using the two trim capacitors. An important clarification for the following discussion is that the trim capacitors are in series with the crystal not parallel. It is a common misconception that load capacitors are in parallel with the crystal and should be approximately equal to the load capacitance of the crystal. This is not true. Figure 1. Crystal Capacitive Clarification X2 X1 Cs1 Cs2 Trace 2.8 pF XTAL Ce1 C e2 Trim 33 pF Use the following formulas to calculate the trim capacitor values for Ce1 and Ce2. Load Capacitance (each side) Ce = 2 * CL – (Cs + Ci) Total Capacitance (as seen by the crystal) CLe = 1 1 ( Ce1 + Cs1 + Ci1 + 1 Ce2 + Cs2 + Ci2 ) CL ....................................................Crystal load capacitance CLe ......................................... Actual loading seen by crystal using standard value trim capacitors Calculating Load Capacitors In addition to the standard external trim capacitors, trace capacitance and pin capacitance must also be considered to correctly calculate crystal loading. As mentioned previously, the capacitance on each side of the crystal is in series with the crystal. This means the total capacitance on each side of the crystal must be twice the specified crystal load capacitance (CL). While the capacitance on each side of the crystal is in series with the crystal, trim capacitors (Ce1,Ce2) should be calculated to provide equal capacitive loading on both sides. Document #: 001-05675 Rev. *C Ce ..................................................... External trim capacitors Cs ..............................................Stray capacitance (terraced) Ci .......................................................... Internal capacitance (lead frame, bond wires etc.) Multifunction Pin Selection In the CY28551, some of the pins can provide different types of frequency, depending on the SEL[1:0] HW strapping pin setting, to support different chipset vendors. The configuration is shown as follows: SEL[1:0] LINK/DOT/SA TA SATA/PCIE Platform 00 LINK SATA SIS 01 DOT SATA Intel W/Gfx 10 LINK PCIEX VIA 11 SATA PCIEX Intel Page 13 of 30 CY28551 Dynamic Frequency 0. The allowable values for M are detailed in the frequency select table (Table 1). Dynamic Frequency – Dynamic Frequency (DF) is a technique used to increase CPU frequency or SRC frequency dynamically from any starting value. The user selects the starting point, either by HW, FSEL, or DAF, then enables DF. After that, DF will dynamically change as determined by DF-N registers and the M value of frequency table. SRC_DAF Enable – This bit enables SRC DAF mode. By default, it is not set. When set, the operating frequency is determined by the values entered into the SRC_DAF_N register. Note: The SRC_DAF_N register must contain valid values before SRC_DAF is set. Default = 0, (No DAF). DF Pin – There are two pins to be used on Dynamic Frequency (DF). When used as DF, these two pins will map to four DF-N registers that correspond to different “N” values for Dynamic Frequency. Any time there is a change in DF, it should load the new value. DOC[2:1] DOC N register 00 Original Frequency 01 DF1_N 10 DF2_N 11 DF3_N DF_EN bit – This bit enables the DF mode. By default, it is not set. When set, the operating frequency is determined by DF[2:0] pins. Default = 0, (No DF) Dial-A-Frequency (CPU & PCIEX) This feature allows users to overclock their systems by slowly stepping up the CPU or SRC frequency. When the programmable output frequency feature is enabled, the CPU and SRC frequencies are determined by the following equation: Fcpu = G * N/M or Fcpu = G2 * N, where G2 = G/M. ‘N’ and ‘M’ are the values programmed in Programmable Frequency Select N-Value Register and M-Value Register, respectively. ‘G’ stands for the PLL Gear Constant, which is determined by the programmed value of FS[E:A]. See Table 1 for the Gear Constant for each Frequency selection. The PCI Express only allows user control of the N register; the M value is fixed and documented in Table 1. In this mode, the user writes the desired N and M value into the DAF I2C registers. The user cannot change only the M value and must change both the M and the N values at the same time, if they require a change to the M value. The user may change only the N value if required. Associated Register Bits CPU_DAF Enable – This bit enables CPU DAF mode. By default, it is not set. When set, the operating frequency is determined by the values entered into the CPU_DAF_N register. Note: The CPU_DAF_N and M register must contain valid values before CPU_DAF is set. Default = 0, (No DAF). CPU_DAF_N – There are nine bits (for 512 values) to linearly change the CPU frequency (limited by VCO range). Default = 0, (0000). The allowable values for N are detailed in the frequency select table (Table 1). CPU_DAF_M – There are 7 bits (for 128 values) to linearly change the CPU frequency (limited by VCO range). Default = Document #: 001-05675 Rev. *C SRC_DAF_N – There are nine bits (for 512 values) to linearly change the CPU frequency (limited by VCO range). Default = 0, (0000). The allowable values for N are detailed in the frequency select table (Table 1). Recovery – The recovery mechanism during CPU DAF, when the system locks up and the watchdog timer is enabled, is determined by the “Watchdog Recovery Mode” and “Watchdog Autorecovery Enable” bits. The possible recovery methods are: (A) Auto, (B) Manual (by Recovery N), (C) HW, and (D) No recovery, just send reset signal. There is no recovery mode for SRC Dial-a-Frequency. Software Frequency Select This mode allows the user to select the CPU output frequencies using the Software Frequency select bits in the SMBUS register. FSEL – There are four bits (for 16 combinations) to select predetermined CPU frequencies from a table. The table selections are detailed in Table 1. FS_Override – This bit allows the CPU frequency to be selected from HW or FSEL settings. By default, this bit is not set and the CPU frequency is selected by HW. When this bit is set, the CPU frequency is selected by the FSEL bits. Default = 0. Recovery – The recovery mechanism during FSEL when the system locks up is determined by the “Watchdog Recovery Mode” and “Watchdog Autorecovery Enable” bits. The only possible recovery method is to use Hardware Settings. Auto recovery or manual recovery can cause a wrong output frequency because the output divider may have changed with the selected CPU frequency and these recovery methods will not recover the original output divider setting. Smooth Switching The device contains one smooth switch circuit, which is shared by the CPU PLL and SRC PLL. The smooth switch circuit ensures that when the output frequency changes by overclocking, the transition from the old frequency to the new frequency is a slow, smooth transition containing no glitches. The rate of change of output frequency when using the smooth switch circuit is less than 1 MHz/0.667 µs. The frequency overshoot and undershoot will be less than 2%. The smooth switch circuit can be assigned auto or manual mode. In auto mode, the clock generator will assign smooth switch automatically when the PLL will perform overclocking. For manual mode, the smooth switch circuit can be assigned to either PLL via SMBUS. By default the smooth switch circuit is set to auto mode. Either PLL can still be overclocked when it does not have control of the smooth switch circuit, but it is not guaranteed to transition to the new frequency without large frequency glitches. Page 14 of 30 CY28551 Do not enable overclocking and change the N values of both PLLs in the same SMBUS block write and use smooth switch mechanism on spread spectrum on/off. Watchdog Timer Watchdog Autorecovery Enable – This bit is set by default and the recovered values are automatically written into the “Watchdog Recovery Register” and reloaded by the Watchdog function. When this bit is not set, the user is allowed to write to the “Watchdog Recovery Register”. The value stored in the “Watchdog Recovery Register” will be used for recovery. Default = 1, Autorecovery. The Watchdog timer is used in the system in conjunction with overclocking. It is used to provide a reset to a system that has hung up due to overclocking the CPU and the Front side bus. The watchdog is enabled by the user and if the system completes its checkpoints, the system will clear the timer. However, when the timer runs out, there will be a reset pulse generated on the SRESET# pin for 20 ms that is used to reset the system. Watchdog Recovery Modes When the Watchdog is enabled (WD_EN = 1) the Watchdog timer will start counting down from a value of Watchdog_timer * time scale. If the Watchdog timer reaches 0 before the WD_EN bit is cleared then it will assert the SRESET# signal and set the Watchdog Alarm bit to ‘1’. There are three operating modes that require Watchdog recovery. The modes are Dial-A-Frequency (DAF), Dynamic Clocking (DF), or Frequency Select. There are four different recovery modes; the following sections list the operating mode and the recovery mode associated with it. To use the watchdog, the SRESET# pin must be enabled by sampling SRESET_EN pin LOW by VTTPWRGD# assertion during system boot up. Recover to Hardware M, N, O If at any point during the Watchdog timer countdown the time stamp or Watchdog timer bits are changed, the timer will reset and start counting down from the new value. After the Reset pulse, the watchdog will stay inactive until either: 1. A new time stamp or watchdog timer value is loaded. 2. The WD_EN bit is cleared and then set again. Watchdog Register Bits The following register bits are associated with the Watchdog timer: Watchdog Enable – This bit (by default) is not set, which disables the Watchdog. When set, the Watchdog is enabled. Also, when there is a transition from LOW to HIGH, the timer reloads. Default = 0, disable Watchdog Timer – There are three bits (for seven combinations) to select the timer value. Default = 000, the value '000' is a reserved test mode. Watchdog Alarm – This bit is a flag and when it is set, it indicates that the timer has expired. This bit is not set by default. When the bit is set, the user is allowed to clear. Default = 0. Watchdog Time Scale – This bit selects the multiplier. When this bit is not set, the multiplier will be 250 ms. When set (by default), the multiplier will be 3s. Default = 1 Watchdog Reset Mode – This selects the Watchdog Reset Mode. When this bit is not set (by default), the Watchdog will send a reset pulse and reload the recovery frequency depending on the Watchdog Recovery Mode setting. When set, it sends a reset pulse. Default = 0, Reset & Recover Frequency. Watchdog Recovery Mode – This bit selects the location to recover from. One option is to recover from the HW settings (already stored in SMBUS registers for readback capability) and the second is to recover from a register called “Recovery N”. Default = 0 (Recover from the HW setting) Document #: 001-05675 Rev. *C Watchdog Recovery Register – This is a nine-bit register to store the watchdog N recovery value. This value can be written by the Autorecovery or User depending on the state of the “Watchdog Autorecovery Enable bit”. When this recovery mode is selected, in the event of a Watchdog timeout, the original M, N, and O values that were latched by the HW FSEL pins at chip boot-up will be reloaded. Autorecovery When this recovery mode is selected, in the event of a Watchdog timeout, the M and N values stored in the Recovery M and N registers will be reloaded. The current values of M and N will be latched into the internal recovery M and N registers by the WD_EN bit being set. Manual Recovery When this recovery mode is selected, in the event of a Watchdog timeout, the N value as programmed by the user in the N recovery register, and the M value that is stored in the Recovery M register (not accessible by the user), will be restored. The current M value will be latched to M recovery register by the WD_EN bit being set. No Recovery If no recovery mode is selected, in the event of a Watchdog time out, the device will assert the SRESET# and keep the current values of M and N Software Reset Software reset is a reset function that is used to send out a pulse from the SRESET# pin. It is controlled by the SW_RESET enable register bit. Upon completion of the byte/word/block write in which the SW_RESET bit was set, the device will send a RESET pulse on the SRESET# pin. The duration of the SRESET# pulse will be the same as the duration of the SRESET# pulse after a Watchdog timer time out. After the SRESET# pulse is asserted the SW_RESET bit will be automatically cleared by the device. PD Clarification The VTT_PWRGD#/PD pin is a dual-function pin. During initial power up, the pin functions as VTT_PWRGD#. Once Page 15 of 30 CY28551 VTT_PWRGD# has been sampled low by the clock chip, the pin assumes PD functionality. The PD pin is an asynchronous active HIGH input used to shut off all clocks cleanly prior to shutting off power to the device. This signal must be synchronized internal to the device prior to powering down the clock synthesizer. PD is also an asynchronous input for powering up the system. When PD is asserted HIGH, all clocks must be driven to a LOW value and held prior to turning off the VCOs and the crystal oscillator PD Assertion When PD is sampled HIGH by two consecutive rising edges of CPUC, all single-ended outputs must be held LOW on their next HIGH-to-LOW transition and differential clocks must be held HIGH or tri-stated (depending on the state of the control register drive mode bit) on the next “Diff clock#” HIGH-to-LOW transition within 4 clock periods. When the SMBus PD drive mode bit corresponding to the differential (CPU, SRC, and DOT) clock output of interest is programmed to '0', the clock output must be held with “Diff clock” pin driven HIGH at 2 x Iref, and “Diff clock#” tri-state. If the control register PD drive mode bit corresponding to the output of interest is programmed to ‘1’, then both the “Diff clock” and the “Diff clock#” are tri-state. Note Figure 3 shows CPUT = 133 MHz and PD drive mode = '1' for all differential outputs. This diagram and description is applicable to valid CPU frequencies 100, 133, 166, and 200 MHz. In the event that PD mode is desired as the initial power-on state, PD must be asserted HIGH in less than 10 µs after asserting VTT_PWRGD#. PD Deassertion The power-up latency must be less than 1.8 ms. This is the time from the deassertion of the PD pin or the ramping of the power supply until the time that stable clocks are output from the clock chip. All differential outputs stopped in a tri-state condition resulting from power down must be driven HIGH in less than 300 µs of PD deassertion to a voltage greater than 200 mV. After the clock chip's internal PLL is powered up and locked, all outputs are to be enabled within a few clock cycles of each other. Figure 4 is an example showing the relationship of clocks coming up. Unfortunately, we can not show all possible combinations; designers need to ensure that from the first active clock output to the last takes no more than two full PCI clock cycles. Figure 3. PD Assertion Timing Waveform PD C PUT, 133 M H z C PUC , 133 M H z SR CT 100 M H z SR CC 100 M H z L IN K U SB, 48 M H z D O T96T D O T96C P C I, 3 3 M H z REF Document #: 001-05675 Rev. *C Page 16 of 30 CY28551 Figure 4. PD Deassertion Timing Waveform T s t a b le < 1 .8 m s PD C PU T, 133 M H z C PU C , 133 M H z SR C T 100 M H z SR C C 100 M H z L IN K U SB, 48 M H z DO T96T DO T96C P C I, 3 3 M H z REF T d r iv e _ P W R D N # <300 µs > 200 m V CPU_STP# Clarification The CPU_STP# signal is an active LOW input used for cleanly stopping and starting the CPU outputs while the rest of the clock generator continues to function. Note that the assertion and deassertion of this signal is absolutely asynchronous. CPU_STP# Assertion while the rest of the clock generator continues to function. When the CPU_STP# pin is asserted, all CPU outputs that are set with the SMBus configuration to be stoppable via assertion of CPU_STP# will be stopped after being sampled by 2 to 6 rising edges of the internal CPUC clock. The final state of the stopped CPU clock is LOW due to tri-state; both CPUT and CPUC outputs will not be driven. The CPU_STP# signal is an active LOW input used for synchronous stopping and starting of the CPU output clocks Figure 5. CPU_STP# Assertion Timing Waveform CPU_STP# CPUT CPUC Figure 6. CPU_STP# Deassertion CPU_STP# CPUT CPUC C P U T In t e r n a l C P U C In t e r n a l T d r iv e _ C P U _ S T P # , 1 0 n S > 2 0 0 m V CPU_STP# Deassertion The deassertion of the CPU_STP# signal will cause all CPU Document #: 001-05675 Rev. *C outputs that were stopped to resume normal operation in a synchronous manner, synchronous manner meaning that no Page 17 of 30 CY28551 short or stretched clock pulses will be produced when the clock resumes. The maximum latency from the deassertion to active outputs is between 2 and 6 CPU clock periods (2 clocks are shown). If the control register tri-state bit corresponding to the output of interest is programmed to '1', then the stopped CPU outputs will be driven HIGH within 10 ns of CPU_Stop# deassertion to a voltage greater than 200 mV. HIGH-to-LOW transition. After the PCI clocks are latched LOW, the stoppable PCIEX clocks will latch to LOW due to tri-state, as shown in Figure 7. The one PCI clock latency shown is critical to system functionality; any violation of this may result in system failure. The Tsu_pci_stp# is the setup time required by the clock generator to correctly sample the PCI_STP# assertion. This time is 10 ns minimum. PCI_STP# Clarification PCI_STP# Deassertion The PCI_STP# signal is an active LOW input used for cleanly stopping and starting the PCI and PCIEX outputs while the rest of the clock generator continues to function. The PCIF and PCIEX clocks are special in that they can be programmed to ignore PCI_STP# by setting the register bit corresponding to the output of interest to free running. Outputs set to free running will ignore the PCI_STP# pin. PCI_STP# Assertion The impact of asserting the PCI_STP# signal is as follows. The clock chip is to sample the PCI_STP# signal on a rising edge of PCIF clock. After detecting the PCI_STP# assertion LOW, all PCI and stoppable PCIF clocks will latch LOW on their next The deassertion of the PCI_STP# signal functions as follows. The deassertion of the PCI_STP# signal is to be sampled on the rising edge of the PCIF free running clock domain. After detecting PCI_STP# deassertion, all PCI, stoppable PCIF and stoppable PCIEX clocks will resume in a glitch-free manner. The PCI and PCIEX clock resume latency should exactly match the 1 PCI clock latency required for PCI_STP# entry. The stoppable PCIEX clocks must be driven HIGH within 15 ns of PCI_STP# deassertion. Figure 8 shows the appropriate relationship. The Tsu_cpu_stp# is the setup time required by the clock generator to correctly sample the PCI_STP# deassertion. This time is 10 ns minimum. Figure 7. PCI_STP# Assertion Tsu _ p c i_ stp # > P C I_ S T P # 1 0 ns P C I_ F PC I P C IE X 1 00 M H z Figure 8. PCI_STP# Deassertion Tdrive_PCIEX <15 ns PCI_STP# PCI_F PCI PCIEX 100MHz CLKREQ# Clarification The CLKREQ# signals are active LOW inputs used to cleanly stop and start selected SRC outputs. The outputs controlled by CLKREQ# are determined by the settings in register bytes Document #: 001-05675 Rev. *C 10 and 11. The CLKREQ# signal is a debounced signal in that its state must remain unchanged during two consecutive rising edges of DIFC to be recognized as a valid assertion or deassertion. (The assertion and deassertion of this signal is absolutely asynchronous.) Page 18 of 30 CY28551 CLKREQ# Assertion CLKREQ# Deassertion All differential outputs that were stopped will resume normal operation in a glitch-free manner. The maximum latency from the deassertion to active outputs is between 2 and 6 PCIEX clock periods (2 clocks are shown) with all CLKREQ# outputs resuming simultaneously. If the CLKREQ# drive mode is tri-state, all stopped PCIEX outputs must be driven HIGH within 10 ns of CLKREQ# deassertion to a voltage greater than 200 mV. The impact of asserting the CLKREQ# pins is that all DIF outputs that are set in the control registers to stoppable via assertion of CLKREQ# are to be stopped after their next transition. When the control register CLKREQ# drive mode bit is programmed to '0', the final state of all stopped PCIEX signals is PCIEXT clock = HIGH and PCIEXC = LOW. There will be no change to the output drive current values. SRCT will be driven HIGH with a current value equal 6 x Iref. When the control register CLKREQ# drive mode bit is programmed to '1', the final state of all stopped DIF signals is LOW; both PCIEXT clock and PCIEXC clock outputs will not be driven. Figure 9. CLKREQ# Deassertion PE_REQ # PCIEXT(free running) PCIEXC (free running) PCIEXT(stoppable) Tdrive_PE_R EQ # < 10 ns PCIEXC(stoppable) Figure 10. VTT_PWRGD# Timing Diagram S2 S1 Delay > 0.25 ms VTT_PWRGD# = Low Sample Inputs straps VDD_A = 2.0V Wait for <1.8 ms S0 Power Off S3 VDD_A = off Normal Operation Enable Outputs VTT_PWRGD# = toggle Document #: 001-05675 Rev. *C Page 19 of 30 CY28551 Figure 11. VTT_PWRGD# Timing Diagram FS_[D:A] VTT_PWRGD# PWRGD_VRM 0.2-0.3 ms Delay VDD Clock Gen Clock State Clock Outputs Clock VCO State 0 Wait for VTT_PWRGD# State 1 State 2 Off Off Document #: 001-05675 Rev. *C Device is not affected, VTT_PWRGD# is ignored Sample Sels State 3 On On Page 20 of 30 CY28551 Absolute Maximum Conditions Parameter Description Condition Min. Max. Unit VDD Core Supply Voltage –0.5 4.6 V VDD_A Analog Supply Voltage –0.5 4.6 V VIN Input Voltage Relative to VSS –0.5 VDD + 0.5 VDC TS Temperature, Storage Non-functional –65 150 °C TA Temperature, Operating Ambient Functional 0 70 °C TJ Temperature, Junction Functional – 150 °C ØJC Dissipation, Junction to Case Mil-STD-883E Method 1012.1 – 20 °C/W ØJA Dissipation, Junction to Ambient JEDEC (JESD 51) – 60 °C/W ESDHBM ESD Protection (Human Body Model) MIL-STD-883, Method 3015 – V UL-94 Flammability Rating At 1/8 in. MSL Moisture Sensitivity Level 2000 V–0 1 Multiple Supplies: The voltage on any input or I/O pin cannot exceed the power pin during power-up. Power supply sequencing is NOT required. DC Electrical Specifications Parameter Description Condition All VDDs 3.3V Operating Voltage 3.3 ± 5% VILI2C Input Low Voltage SDATA, SCLK VIHI2C Input High Voltage SDATA, SCLK VIL_FS FS_[A:D] Input Low Voltage VIH_FS FS_[A:D] Input High Voltage VIL 3.3V Input Low Voltage Min. Max. Unit 3.135 3.465 V – 1.0 V 2.2 – V VSS – 0.3 0.35 V 0.7 VDD + 0.5 V VSS – 0.3 0.8 V VIH 3.3V Input High Voltage 2.0 VDD + 0.3 V IIL Input Low Leakage Current Except internal pull-up resistors, 0 < VIN < VDD –5 – µA IIH Input High Leakage Current Except internal pull-down resistors, 0 < VIN < VDD – 5 µA VOL 3.3V Output Low Voltage IOL = 1 mA – 0.4 V IOH = –1 mA VOH 3.3V Output High Voltage IOZ High-impedance Output Current CIN COUT LIN Pin Inductance VXIH Xin High Voltage VXIL Xin Low Voltage IDD3.3V Dynamic Supply Current At max. load and freq. per Figure 14 IPT3.3V Power-down Supply Current PD asserted, Outputs Tri-state – 2.4 – V –10 10 µA Input Pin Capacitance 3 5 pF Output Pin Capacitance 3 5 pF Document #: 001-05675 Rev. *C – 7 nH 0.7VDD VDD V 0 0.3VDD V – 500 mA 12 mA Page 21 of 30 CY28551 AC Electrical Specifications Parameter Description Condition Min. Max. Unit 47.5 52.5 % 69.841 71.0 ns – 10.0 ns Crystal TDC XIN Duty Cycle The device will operate reliably with input duty cycles up to 30/70 but the REF clock duty cycle will not be within specification TPERIOD XIN Period When XIN is driven from an external clock source TR/TF XIN Rise and Fall Times Measured between 0.3VDD and 0.7VDD TCCJ XIN Cycle to Cycle Jitter As an average over 1-µs duration – 500 ps LACC Long-term Accuracy Over 150 ms – 30 ppm CPU at 0.7V (SSC refers to –0.5% spread spectrum) TDC CPUT and CPUC Duty Cycle Measured at crossing point VOX @ 0.1s 45 55 % TPERIOD 100 MHz CPUT and CPUC Period Measured at crossing point VOX @ 0.1s 9.99900 10.0100 ns TPERIOD 133 MHz CPUT and CPUC Period Measured at crossing point VOX @ 0.1s 7.49925 7.50075 ns TPERIOD 166 MHz CPUT and CPUC Period Measured at crossing point VOX @ 0.1s 5.99940 6.00060 ns TPERIOD 200 MHz CPUT and CPUC Period Measured at crossing point VOX @ 0.1s 4.99950 5.00050 ns TPERIOD 266 MHz CPUT and CPUC Period Measured at crossing point VOX @ 0.1s 3.74963 3.75038 ns TPERIOD 333 MHz CPUT and CPUC Period Measured at crossing point VOX @ 0.1s 2.99970 3.00030 ns TPERIOD 400 MHz CPUT and CPUC Period Measured at crossing point VOX @ 0.1s 2.49975 2.50025 ns TPERIODSS 100 MHz CPUT and CPUC Period, SSC Measured at crossing point VOX @ 0.1s 9.99900 10.0100 ns TPERIODSS 133 MHz CPUT and CPUC Period, SSC Measured at crossing point VOX @ 0.1s 7.49925 7.50075 ns TPERIODSS 166 MHz CPUT and CPUC Period, SSC Measured at crossing point VOX @ 0.1s 5.99940 6.00060 ns TPERIODSS 200 MHz CPUT and CPUC Period, SSC Measured at crossing point VOX @ 0.1s 4.99950 5.00050 ns TPERIODSS 266 MHz CPUT and CPUC Period, SSC Measured at crossing point VOX @ 0.1s 3.74963 3.75038 ns TPERIODSS 333 MHz CPUT and CPUC Period, SSC Measured at crossing point VOX @ 0.1s 2.99970 3.00030 ns TPERIODSS 400 MHz CPUT and CPUC Period, SSC Measured at crossing point VOX @ 0.1s 2.49975 2.50025 ns TPERIODAbs 100 MHz CPUT and CPUC Absolute period Measured at crossing point VOX @ 1 clock 9.91400 10.0860 ns TPERIODAbs 133 MHz CPUT and CPUC Absolute Period Measured at crossing point VOX @ 1 clock 7.41425 7.58575 ns TPERIODAbs 166 MHz CPUT and CPUC Absolute Period Measured at crossing point VOX @ 1 clock 5.91440 6.08560 ns TPERIODAbs 200 MHz CPUT and CPUC Absolute Period Measured at crossing point VOX @ 1 clock 4.91450 5.08550 ns TPERIODAbs 266 MHz CPUT and CPUC Absolute Period Measured at crossing point VOX @ 1 clock 3.66463 3.83538 ns TPERIODAbs 333 MHz CPUT and CPUC Absolute Period Measured at crossing point VOX @ 1 clock 2.91470 3.08530 ns TPERIODAbs 400 MHz CPUT and CPUC Absolute Period Measured at crossing point VOX @ 1 clock 2.41475 2.58525 ns TPERIODSSAbs 100- MHz CPUT and CPUC Absolute Period, SSC Measured at crossing point VOX @ 1 clock 9.91400 10.1363 ns TPERIODSSAbs 133 MHz CPUT and CPUC Absolute Period, SSC Measured at crossing point VOX @ 1 clock 7.41425 7.62345 ns TPERIODSSAbs 166 MHz CPUT and CPUC Absolute Period, SSC Measured at crossing point VOX @ 1 clock 5.91440 6.11576 ns Document #: 001-05675 Rev. *C Page 22 of 30 CY28551 AC Electrical Specifications (continued) Min. Max. Unit TPERIODSSAbs 200 MHz CPUT and CPUC Absolute Period, SSC Parameter Description Measured at crossing point VOX @ 1 clock Condition 4.91450 5.11063 ns TPERIODSSAbs 266 MHz CPUT and CPUC Absolute Period, SSC Measured at crossing point VOX @ 1 clock 3.66463 3.85422 ns TPERIODSSAbs 333 MHz CPUT and CPUC Absolute Period, SSC Measured at crossing point VOX @ 1 clock 2.91470 3.10038 ns TPERIODSSAbs 400 MHz CPUT and CPUC Absolute Period, SSC Measured at crossing point VOX @ 1 clock 2.41475 2.59782 ns Measured at crossing point VOX – 100 ps TSKEW CPU0 to CPU1 TCCJ CPUT/C Cycle to Cycle Measured at crossing point VOX – 85 ps LACC Long Term Accuracy Measured at crossing point VOX – 100 ppm TR/TF CPUT and CPUC Rise and Fall Times Measured differentially from ±150 mV 2.5 8 V/ns TRFM Rise/Fall Matching Measured single-endedly from ±75 mV – 20 % V_max Max Output Voltage Math averages Figure 14 – 1.15 V V_min Min Output Voltage Math averages Figure 14 –0.3 – V VOX Crossing Point Voltage at 0.7V Swing 300 550 mV 2 7 V/ns CPU at 3.3V (SSC refers to –0.5% spread spectrum) TR Output Rise Edge Rate Measured @ K8 test load using VOCM ± 400 mV, 0.850V to 1.650V TF Output Fall Edge Rate Measured @ K8test load using VOCM ± 400 mV, 1.650V to 0.850V 2 7 V/ns VDIFF Differential Voltage Measured @ K8 test load (single-ended) 0.4 2.3 V ∆DIFF Change in VDIFF_DC Magnitude Measured @ K8 test load (single-ended) –150 150 mV VCM Common Mode Voltage Measured @ K8 test load (single-ended) 1.05 1.45 V ∆VCM Change in VCM Measured @ K8 test load (single-ended) –200 200 mV TDC Duty Cycle Measured at VOX 45 53 % TCYC Jitter, Cycle to Cycle Measured at VOX 0 200 ps TACCUM Jitter, Accumulated Measured at VOX –1000 1000 ps PCIEX TDC PCIEXT and PCIEXC Duty Cycle Measured at crossing point VOX 45 55 % TPERIOD 100 MHz PCIEXT and PCIEXC Period Measured at crossing point VOX @ 0.1s 9.99900 10.0010 ns TPERIODSS 100 MHz PCIEXT and PCIEXC Period, Measured at crossing point VOX @ 0.1s SSC 9.99900 10.0010 ns TPERIODAbs 100 MHz PCIEXT and PCIEXC Absolute Measured at crossing point VOX Period @ 1 clock 9.87400 10.1260 ns TPERIODSSAbs 100 MHz PCIEXT and PCIEXC Absolute Measured at crossing point VOX Period, SSC @ 1 clock 9.87400 10.1763 ns Measured at crossing point VOX – 250 ps TSKEW Any PCIEXT/C to PCIEXT/C Clock Skew TCCJ PCIEXT/C Cycle to Cycle Jitter Measured at crossing point VOX – 125 ps LACC PCIEXT/C Long Term Accuracy Measured at crossing point VOX – 100 ppm TR/TF PCIEXT and PCIEXC Rise and Fall Times Measured differentially from ±150 mV 2.5 8 V/ns TRFM Rise/Fall Matching Measured single-endedly from ±75 mV – 20 % V_max Max Output Voltage Math averages, see Figure 14 – 1.15 V V_min Min Output Voltage Math averages, see Figure 14 –0.3 – V Document #: 001-05675 Rev. *C Page 23 of 30 CY28551 AC Electrical Specifications (continued) Parameter Description Condition Min. Max. Unit 300 550 mV VOX Crossing Point Voltage at 0.7V Swing DOT TDC DOT96T and DOT96C Duty Cycle Measured at crossing point VOX 45 55 % TPERIOD DOT96T and DOT96C Period Measured at crossing point VOX @ 0.1s 10.4156 10.4177 ns TPERIODAbs DOT96T and DOT96C Absolute Period Measured at crossing point VOX @ 0.1s 10.1656 10.6677 ns TCCJ DOT96T/C Cycle to Cycle Jitter – 250 ps LACC DOT96T/C Long Term Accuracy Measured at crossing point VOX – 300 ppm TLTJ Long Term Jitter Measurement taken from cross point VOX @ 10 µs – 700 ps TR/TF DOT96T and DOT96C Rise and Fall Time Measured differentially from ±150 mV 2.5 8 V/ns TRFM Rise/Fall Matching Measured single-endedly from ±75 mV – 20 % Measured at crossing point VOX V_max Max Output Voltage Math averages, see Figure 14 – 1.15 V V_min Min Output Voltage Math averages, see Figure 14 –0.3 – V VOX Crossing Point Voltage at 0.7V Swing 300 550 mV LINK - 133 MHz TDC LINK (133 MHz) Duty Cycle 45 55 % TPERIOD Spread Disabled LINK (133 MHz) Period Measurement at 1.5V 7.50 7.56 ns TPERIODSS Spread Enabled LINK (133 MHz) Period, Measurement at 1.5V SSC 7.50 7.56 ns TR/TF LINK (133 MHz) Rising and Falling Edge Measured between 0.8V and 2.0V Rate 1.0 4.0 V/ns TCCJ LINK (133 MHz) Cycle-to-cycle Jitter Measurement at 1.5V – 250 ps TSKEW Any LINK Clock Skew Measurement at 1.5V – 175 ps LACC LINK (133 MHz) Long Term Accuracy Measured at crossing point VOX – 300 ppm TDC LINK (66 MHz) Duty Cycle Measurement at 1.5V 45 55 % TPERIOD Spread Disabled LINK (66 MHz) Period Measurement at 1.5V 14.9955 15.0045 ns TPERIODSS Spread Enabled LINK (66 MHz) Period, Measurement at 1.5V SSC 14.9955 15.0045 ns TR/TF LINK (66 MHz) Rising and Falling Edge Measured between 0.8V and 2.0V Rate 1.0 4.0 V/ns TCCJ LINK (66 MHz) Cycle-to-cycle Jitter Measurement at 1.5V – 250 ps TSKEW Any LINK Clock Skew Measurement at 1.5V – 175 ps Measurement at 1.5V LINK - 66 MHz LACC LINK (66 MHz) Long Term Accuracy Measured at crossing point VOX – 300 ppm PCI TDC PCI Duty Cycle Measurement at 1.5V 45 55 % TPERIOD Spread Disabled PCIF/PCI Period Measurement at 1.5V 29.99100 30.00900 ns TPERIODSS Spread Enabled PCIF/PCI Period, SSC Measurement at 1.5V 29.9910 30.15980 ns TPERIODAbs Spread Disabled PCIF/PCI Period Measurement at 1.5V 29.49100 30.50900 ns TPERIODSSAbs Spread Enabled PCIF/PCI Period, SSC Measurement at 1.5V 29.49100 30.65980 ns THIGH PCIF and PCI High Time Measurement at 2.4V 12.0 – ns TLOW PCIF and PCI Low Time Measurement at 0.4V 12.0 – ns TR/TF PCIF and PCI Rising and Falling Edge Measured between 0.8V and 2.0V Rate 1.0 4.0 V/ns Document #: 001-05675 Rev. *C Page 24 of 30 CY28551 AC Electrical Specifications (continued) Min. Max. Unit TSKEW Parameter Any PCI Clock to Any PCI Clock Skew Measurement at 1.5V Description Condition – 250 ps TCCJ PCIF and PCI Cycle to Cycle Jitter Measurement at 1.5V – 500 ps TDC Duty Cycle Measurement at 1.5V In High Drive mode 45 55 % TPERIOD Period Measurement at 1.5V 20.83125 20.83542 ns TPERIODAbs Absolute Period Measurement at 1.5V 20.48125 21.18542 ns USB THIGH USB High Time Measurement at 2.4V 8.094 10.5 ns TLOW USB Low Time Measurement at 0.4V 7.694 10.5 ns TR/TF Rising and Falling Edge Rate Measured between 0.8V and 2.0V 1.0 2.0 V/ns TCCJ Cycle-to-cycle Jitter Measurement at 1.5V – 350 ps LACC 48M Long Term Accuracy Measured at crossing point VOX – 100 ppm TLTJ Long Term Jitter Measurement taken from cross point VOX @ 1 µs – 1.0 ns 24M TDC Duty Cycle Measurement at 1.5V In High Drive mode 45 55 % TPERIOD Period Measurement at 1.5V 41.6646 41.6688 ns THIGH USB High Time Measurement at 2.4V 18.8323 18.8323 ns TLOW USB Low Time Measurement at 0.4V 18.8323 18.8323 ns TR/TF Rising and Falling Edge Rate Measured between 0.8V and 2.0V 1.0 4.0 V/ns TCCJ Cycle-to-cycle Jitter Measurement at 1.5V – 350 ps LACC 48M Long Term Accuracy Measured at crossing point VOX – 100 ppm TLTJ Long Term jitter Measurement taken from cross point VOX @ 1 µs – 1.0 ns REF TDC REF Duty Cycle Measurement at 1.5V 45 55 % TPERIOD REF Period Measurement at 1.5V 69.8203 69.8622 ns TPERIODAbs REF Absolute Period Measurement at 1.5V 68.82033 70.86224 ns TR/TF REF Rise and Fall Times Edge rate Measured between 0.8V and 2.0V 1.0 4.0 V/ns TCCJ REF Cycle-to-cycle Jitter Measurement at 1.5V – 1000 ps TSKEW REF Clock to REF Clock Measurement at 1.5V – 500 ps LACC Long Term Accuracy Measurement at 1.5V – 300 ppm – 1.8 ms ENABLE/DISABLE and SET-UP TSTABLE Clock Stabilization from Power-up Document #: 001-05675 Rev. *C Page 25 of 30 CY28551 Test and Measurement Set-up For PCI/USB and 24M Single-ended Signals and Reference Figure 12 and Figure 13 show the test load configurations for the single-ended PCI, USB, 24M, and REF output signals Figure 12. Single-ended Load Configuration. 2 2Ω P C I/U S B 50Ω 1 2Ω 5 0Ω REF 1 2Ω 5 0Ω M e a su re m e n t P o in t 5 pF M e a su re m e n t P o in t 5 pF M e a su re m e n t P o in t 5 pF Figure 13. Single-ended Load Configuration HIGH DRIVE OPTION Measurement Point 12Ω 50Ω PCI/USB Measurement Point 12Ω 50Ω 50Ω 12Ω 50Ω 12Ω 50Ω Document #: 001-05675 Rev. *C 5 pF Measurement Point 12Ω REF 5 pF 5 pF Measurement Point 5 pF Measurement Point 5 pF Page 26 of 30 CY28551 The following diagrams show the test load configuration for the differential CPU and PCIEX outputs. Figure 14. Differential Load Configuration for 0.7V Push Pull Clock L1 M easurem ent Point L2 22Ω OUT+ 50Ω 2 pF L1 = 0.5", L2 = 7" M easurem ent Point 50Ω O U T- L1 22Ω L2 2 pF Figure 15. Differential Load Configuration for 0.7 Push Pull Clock 1 .2 5 V C P U T _K 8 L1 15 O hm L2 TPCB 3900 pF L3 125 O hm M e a s u re m e n t P o in t 5 pF 169 O hm C P U C _K 8 L1 15 O hm L2 1 .2 5 V L3 TP C B 3900 pF 125 O hm M e a s u re m e n t P o in t 5 pF Figure 16. Differential Measurement for Differential Output Signals (for AC Parameters Measurement) Document #: 001-05675 Rev. *C Page 27 of 30 CY28551 Figure 17. Single-ended Measurement for Differential Output Signals (for AC Parameters Measurement) Figure 18. Single-ended Output Signals (for AC Parameters Measurement) Ordering Information Part Number Package Type Product Flow Lead-free CY28551LFXC 64-pin QFN Commercial, 0° to 85°C CY28551LFXCT 64-pin QFN – Tape and Reel Commercial, 0° to 85°C Document #: 001-05675 Rev. *C Page 28 of 30 © Cypress Semiconductor Corporation, 2006. The information contained herein is subject to change without notice. Cypress Semiconductor Corporation assumes no responsibility for the use of any circuitry other than circuitry embodied in a Cypress product. Nor does it convey or imply any license under patent or other rights. Cypress products are not warranted nor intended to be used for medical, life support, life saving, critical control or safety applications, unless pursuant to an express written agreement with Cypress. Furthermore, Cypress does not authorize its products for use as critical components in life-support systems where a malfunction or failure may reasonably be expected to result in significant injury to the user. The inclusion of Cypress products in life-support systems application implies that the manufacturer assumes all risk of such use and in doing so indemnifies Cypress against all charges. CY28551 Package Diagram Figure 19. 64-Lead QFN 9 x 9 mm (Punch Version) LF64A DIMENSIONS IN MM[INCHES] MIN. MAX. REFERENCE JEDEC MO-220 WEIGHT: 0.2 GRAMS 0.08[0.003] 8.90[0.350] 9.10[0.358] A C 1.00[0.039] MAX. 0.05[0.002] MAX. 0.18[0.007] 0.28[0.011] 0.80[0.031] MAX. 8.70[0.342] 8.80[0.346] PIN1 ID 0.20[0.008] R. 0.20[0.008] REF. N N 1 1 0.80 DIA. 2 0.45[0.018] 2 3 8.90[0.350] 9.10[0.358] 8.70[0.342] 8.80[0.346] E-PAD (PAD SIZE VARY BY DEVICE TYPE) 0.30[0.012] 0.50[0.020] 0.24[0.009] 0.60[0.024] 0°-12° 0.50[0.020] TOP VIEW 7.45[0.293] 7.55[0.297] C SEATING PLANE SIDE VIEW BOTTOM VIEW 51-85215-** Purchase of I2C components from Cypress or one of its sublicensed Associated Companies conveys a license under the Philips I2C Patent Rights to use these components in an I2C system, provided that the system conforms to the I2C Standard Specification as defined by Philips. Intel and Pentium are registered trademarks of Intel Corporation. SiS is a registered trademark of Silicon Integrated Systems. Dial-A-Frequency is a registered trademark of Cypress Semiconductor Corporation. All product and company names mentioned in this document are the trademarks of their respective holders. Document #: 001-05675 Rev. *C Page 29 of 30 CY28551 Document History Page Document Title: CY28551 Universal Clock Generator for Intel, VIA, and SIS® Document Number: 001-05675 REV. ECN NO. Issue Date Orig. of Change Description of Change ** 409135 See ECN HGS New Data Sheet *A 417501 See ECN HGS Register alignment changed: -BYTE 9 contains DF3_N8,DF2_N8,DF1_N8 -BYTE 10 contains DF1_N<7:0> -BYTE 11 contains DF2_N<7:0> -BYTE 12 contains DF3_N<7:0> Add POWERGOOD status bit at BYTE6 [0] Add CPU_STP#, PCI_STP# and CLKREQ# description *B 460105 See ECN RGL Minor change – To post on web *C 491596 See ECN HGS 1. Change 48M/24_48M driving strength to high by default 2. Change Revision ID (BYTE7[7:4]) to 0010 Document #: 001-05675 Rev. *C Page 30 of 30