manualshive.com logo in svg

Hotenda MPC8349EA, Технические данные инструкция

"Hotenda MPC8349EA - продукт высокой производительности с техническими характеристиками. Получите бесплатный пользовательский руководство с Технической Описанием на {веб-сайте}. Скачайте свой руководство прямо сейчас и узнайте все возможности этого устройства."

Поделиться
Скачать
background image

Electronic Component Distributor. Source::Freescale Semiconductor

 P.N:MPC8349CZUAGDB Desc:IC MPU POWERQUICC II PRO 672TBGA 
Web:http://www.hotenda.cn E-mail:[email protected] Phone:(+86) 075583794354

MPC8349EA PowerQUICC II Pro Integrated Host Processor Hardware Specifications, Rev. 13

Freescale Semiconductor

81

 

System Design Information

have a low ESR (equivalent series resistance) rating to ensure the quick response time. They should also 
be connected to the power and ground planes through two vias to minimize inductance. Suggested bulk 
capacitors are 100–330 µF (AVX TPS tantalum or Sanyo OSCON).

21.4

Connection Recommendations

To ensure reliable operation, connect unused inputs to an appropriate signal level. Unused active low 
inputs should be tied to OV

DD

, GV

DD

, or LV

DD

 as required. Unused active high inputs should be 

connected to GND. All NC (no-connect) signals must remain unconnected.

Power and ground connections must be made to all external V

DD

, GV

DD

, LV

DD

, OV

DD

, and GND pins of 

the MPC8349EA.

21.5

Output Buffer DC Impedance

The MPC8349EA drivers are characterized over process, voltage, and temperature. For all buses, the 
driver is a push-pull single-ended driver type (open drain for I

2

C).

To measure Z

0

 for the single-ended drivers, an external resistor is connected from the chip pad to OV

DD

 

or GND. Then the value of each resistor is varied until the pad voltage is OV

DD

/2 (see 

Figure 43

). The 

output impedance is the average of two components, the resistances of the pull-up and pull-down devices. 
When data is held high, SW1 is closed (SW2 is open) and R

P

 is trimmed until the voltage at the pad equals 

OV

DD

/2. R

P

 then becomes the resistance of the pull-up devices. R

P

 and R

N

 are designed to be close to each 

other in value. Then, Z

0 

= (R

P 

+ R

N

)

÷

2.

Figure 43. Driver Impedance Measurement

Two measurements give the value of this resistance and the strength of the driver current source. First, the 
output voltage is measured while driving logic 1 without an external differential termination resistor. The 
measured voltage is V

1 

= R

source

 

×

 I

source

. Second, the output voltage is measured while driving logic 1 

with an external precision differential termination resistor of value R

term

. The measured voltage is 

OV

DD

OGND

R

P

R

N

Pad

Data

SW1

SW2

                            81 / 87

Содержание MPC8349EA

Страница 1: ...ated Host Processor Family Reference Manual To locate published errata or updates for this document refer to the MPC8349EA product summary page on our website as listed on the back cover of this docum...

Страница 2: ...al units within the MPC8349EA Figure 1 MPC8349EA Block Diagram Major features of the device are as follows Embedded PowerPC e300 processor core operates at up to 667 MHz High performance superscalar p...

Страница 3: ...I O for DDR1 1 8 V SSTL2 compatible I O for DDR2 Dual three speed 10 100 1000 Ethernet controllers TSECs Dual controllers designed to comply with IEEE 802 3 802 3u 820 3x 802 3z 802 3ac standards Ethe...

Страница 4: ...gorithms Programmable field size up to 2048 bits Elliptic curve cryptography F2m and F p modes Programmable field size up to 511 bits Data encryption standard DES execution unit DEU DES and 3DES algor...

Страница 5: ...speed 12 Mbps and low speed 1 5 Mbps operations Direct connection to a high speed device without an external hub External PHY with serial and low pin count ULPI interfaces Local bus controller LBC Mu...

Страница 6: ...mote PCI masters Misaligned transfer capability Data chaining and direct mode Interrupt on completed segment and chain DUART Two 4 wire interfaces RxD TxD RTS CTS Programming model compatible with the...

Страница 7: ...LVIN 0 3 to LVDD 0 3 V 4 5 Local bus DUART CLKIN system control and power management I2C and JTAG signals OVIN 0 3 to OVDD 0 3 V 3 5 PCI OVIN 0 3 to OVDD 0 3 V 6 Storage temperature range TSTG 55 to...

Страница 8: ...DD Table 2 Recommended Operating Conditions Parameter Symbol Recommended Value Unit Notes Core supply voltage for 667 MHz core frequency VDD 1 3 V 60 mV V 1 Core supply voltage VDD 1 2 V 60 mV V 1 PLL...

Страница 9: ...mates 2 2 Power Sequencing This section details the power sequencing considerations for the MPC8349EA 2 2 1 Power Up Sequencing MPC8349EA does not require the core supply voltage VDD and AVDD and I O...

Страница 10: ...lies fully ramp up In the case where the core voltage is applied first the core voltage supply must rise to 90 of its nominal value before the I O supplies reach 0 7 V see Figure 4 Figure 4 Power Sequ...

Страница 11: ...nd a Dhrystone benchmark application 6 Maximum power is based on a voltage of VDD 1 3 V worst case process a junction temperature of TJ 105 C and an artificial smoke test Table 5 MPC8349EA Typical I O...

Страница 12: ...0 3 0 4 V CLKIN input current 0 V VIN OVDD IIN 10 A PCI_SYNC_IN input current 0 V VIN 0 5 V or OVDD 0 5 V VIN OVDD IIN 10 A PCI_SYNC_IN input current 0 5 V VIN OVDD 0 5 V IIN 50 A Table 7 CLKIN AC Ti...

Страница 13: ...arameter Symbol Min Typical Max Unit Notes EC_GTX_CLK125 frequency tG125 125 MHz EC_GTX_CLK125 cycle time tG125 8 ns EC_GTX_CLK125 rise and fall time LVDD 2 5 V LVDD 3 3 V tG125R tG125F 0 75 1 0 ns 1...

Страница 14: ...on output 16 tPCI_SYNC_IN 1 Input setup time for POR configuration signals CFG_RESET_SOURCE 0 2 and CFG_CLKIN_DIV with respect to negation of PORESET when the MPC8349EA is in PCI host mode 4 tCLKIN 2...

Страница 15: ...lly Addressed by This Document for silicon revision level determination 6 1 DDR and DDR2 SDRAM DC Electrical Characteristics Table 12 provides the recommended operating conditions for the DDR2 SDRAM c...

Страница 16: ...n Symbol Min Max Unit Notes Input output capacitance DQ DQS DQS CIO 6 8 pF 1 Delta input output capacitance DQ DQS DQS CDIO 0 5 pF 1 Note 1 This parameter is sampled GVDD 1 8 V 0 090 V f 1 MHz TA 25 C...

Страница 17: ...DRAM when GVDD typ 2 5 V Table 15 DDR SDRAM Capacitance for GVDD typ 2 5 V Parameter Condition Symbol Min Max Unit Notes Input output capacitance DQ DQS CIO 6 8 pF 1 Delta input output capacitance DQ...

Страница 18: ...ons At recommended operating conditions with GVDD of 1 8 or 2 5 V 5 Parameter Symbol Min Max Unit Notes Controller Skew for MDQS MDQ MECC MDM tCISKEW ps 1 2 400 MHz 600 600 3 333 MHz 750 750 266 MHz 7...

Страница 19: ...1 Min Max Unit Notes ADDR CMD MODT output setup with respect to MCK tDDKHAS ns 3 400 MHz 1 95 333 MHz 2 40 266 MHz 3 15 200 MHz 4 20 ADDR CMD MODT output hold with respect to MCK tDDKHAX ns 3 400 MHz...

Страница 20: ...3 ADDR CMD includes all DDR SDRAM output signals except MCK MCK MCS and MDQ MECC MDM MDQS For the ADDR CMD setup and hold specifications it is assumed that the clock control register is set to adjust...

Страница 21: ...R bus Figure 8 DDR AC Test Load 7 DUART This section describes the DC and AC electrical specifications for the DUART interface of the MPC8349EA 7 1 DUART DC Electrical Characteristics Table 21 provide...

Страница 22: ...terface RGMII and reduced ten bit interface RTBI signals except management data input output MDIO and management data clock MDC The MII GMII and TBI interfaces are defined for 3 3 V and the RGMII and...

Страница 23: ...TBI and MII DC Electrical Characteristics Parameter Symbol Conditions Min Max Unit Supply voltage 3 3 V LVDD 2 2 97 3 63 V Output high voltage VOH IOH 4 0 mA LVDD Min 2 40 LVDD 0 3 V Output low volta...

Страница 24: ...ications follow the pattern t first two letters of functional block signal state reference state for inputs and t first two letters of functional block reference state signal state for outputs For exa...

Страница 25: ...II receive timing GR with respect to the time data input signals D reaching the valid state V relative to the tRX clock reference K going to the high state H or setup time Also tGRDXKL symbolizes GMII...

Страница 26: ...tate for outputs For example tMTKHDX symbolizes MII transmit timing MT for the time tMTX clock reference K going high H until data outputs D are invalid X In general the clock reference symbol is base...

Страница 27: ...state for inputs and t first two letters of functional block reference state signal state for outputs For example tMRDVKH symbolizes MII receive timing MR with respect to the time data input signals...

Страница 28: ...tTTXF 1 0 ns Notes 1 The symbols for timing specifications follow the pattern of t first two letters of functional block signal state reference state for inputs and t first two letters of functional b...

Страница 29: ...TR with respect to the time data input signals D reach the valid state V relative to the tTRX clock reference K going to the high H state or setup time Also tTRDXKH symbolizes TBI receive timing TR w...

Страница 30: ...50 55 Duty cycle for 10BASE T and 100BASE TX3 5 tRGTH tRGT 40 50 60 Rise time 20 80 tRGTR 0 75 ns Fall time 80 20 tRGTF 0 75 ns Notes 1 In general the clock reference symbol for this section is based...

Страница 31: ...I TBI and RTBI are specified in Section 8 1 Three Speed Ethernet Controller TSEC GMII MII TBI RGMII RTBI Electrical Characteristics 8 3 1 MII Management DC Electrical Characteristics The MDC and MDIO...

Страница 32: ...in Max Unit Supply voltage 3 3 V LVDD 2 97 3 63 V Output high voltage VOH IOH 1 0 mA LVDD Min 2 10 LVDD 0 3 V Output low voltage VOL IOL 1 0 mA LVDD Min GND 0 50 V Input high voltage VIH 2 00 V Input...

Страница 33: ...gh H until data outputs D are invalid X or data hold time Also tMDDVKH symbolizes management data timing MD with respect to the time data input signals D reach the valid state V relative to the tMDC c...

Страница 34: ...Notes USB clock cycle time tUSCK 15 ns 2 5 Input setup to USB clock all inputs tUSIVKH 4 ns 2 5 Input hold to USB clock all inputs tUSIXKH 1 ns 2 5 USB clock to output valid all outputs tUSKHOV 7 ns 2...

Страница 35: ...ignals 10 Local Bus This section describes the DC and AC electrical specifications for the local bus interface of the MPC8349EA 10 1 Local Bus DC Electrical Characteristics Table 37 provides the DC el...

Страница 36: ...3 Output hold from local bus clock for LAD LDP tLBKHOX2 1 ns 3 Local bus clock to output high impedance for LAD LDP tLBKHOZ 3 8 ns 8 Notes 1 The symbols for timing specifications follow the pattern o...

Страница 37: ...mple tLBIXKH1 symbolizes local bus timing LB for the input I to go invalid X with respect to the time the tLBK clock reference K goes high H in this case for clock one 1 Also tLBKHOX symbolizes local...

Страница 38: ...Only DLL Enabled Figure 22 Local Bus Signals Nonspecial Signals Only DLL Bypass Mode Output Signals LA 27 31 LBCTL LBCKE LOE LSDA10 LSDWE LSDRAS LSDCAS LSDDQM 0 3 tLBKHOV tLBKHOV tLBKHOV LSYNC_IN Inpu...

Страница 39: ...KDIV 2 DLL Enabled Figure 24 Local Bus Signals GPCM UPM Signals for LCCR CLKDIV 2 DLL Bypass Mode LSYNC_IN UPM Mode Input Signal LUPWAIT tLBIXKH2 tLBIVKH2 tLBIVKH1 tLBIXKH1 tLBKHOZ1 T1 T3 Input Signal...

Страница 40: ...Integrated Host Processor Hardware Specifications Rev 13 40 Freescale Semiconductor Local Bus Figure 25 Local Bus Signals GPCM UPM Signals for LCCR CLKDIV 4 DLL Bypass Mode LCLK UPM Mode Input Signal...

Страница 41: ...E Std 1149 1 JTAG interface of the MPC8349EA 11 1 JTAG DC Electrical Characteristics Table 40 provides the DC electrical characteristics for the IEEE Std 1149 1 JTAG interface of the MPC8349EA Table 4...

Страница 42: ...age VOL IOL 3 2 mA 0 4 V Table 41 JTAG AC Timing Specifications Independent of CLKIN 1 At recommended operating conditions see Table 2 Parameter Symbol2 Min Max Unit Notes JTAG external clock frequenc...

Страница 43: ...ttern of t first two letters of functional block signal state reference state for inputs and t first two letters of functional block reference state signal state for outputs For example tJTDVKH symbol...

Страница 44: ...ndary scan timing diagram Figure 30 Boundary Scan Timing Diagram Figure 31 provides the test access port timing diagram Figure 31 Test Access Port Timing Diagram VM Midpoint Voltage OVDD 2 VM VM tJTDV...

Страница 45: ...level VIL 0 3 0 3 OVDD V Low level output voltage VOL 0 0 2 OVDD V 1 Output fall time from VIH min to VIL max with a bus capacitance from 10 to 400 pF tI2KLKV 20 0 1 CB 250 ns 2 Pulse width of spikes...

Страница 46: ...ing I2 with respect to the time data input signals D reach the valid state V relative to the tI2C clock reference K going to the high H state or setup time Also tI2SXKL symbolizes I2 C timing I2 for t...

Страница 47: ...PCI input clock depending on whether the device is configured as a host or agent device Table 45 provides the PCI AC timing specifications at 66 MHz Table 44 PCI DC Electrical Characteristics Paramete...

Страница 48: ...ge current specification 5 Input timings are measured at the pin 6 The setup and hold time is with respect to the rising edge of PORESET Table 46 PCI AC Timing Specifications at 33 MHz Parameter Symbo...

Страница 49: ...Figure 36 shows the PCI output AC timing diagram Figure 36 PCI Output AC Timing Diagram 14 Timers This section describes the DC and AC electrical specifications for the timers 14 1 Timer DC Electrical...

Страница 50: ...Timers Input AC Timing Specifications1 Parameter Symbol2 Min Unit Timers inputs minimum pulse width tTIWID 20 ns Notes 1 Input specifications are measured from the 50 percent level of the signal to th...

Страница 51: ...the rising edge of CLKIN Timings are measured at the pin 2 GPIO inputs and outputs are asynchronous to any visible clock GPIO outputs should be synchronized before use by external synchronous logic GP...

Страница 52: ...ications1 Parameter Symbol2 Min Max Unit SPI outputs valid Master mode internal clock delay tNIKHOV 6 ns SPI outputs hold Master mode internal clock delay tNIKHOX 0 5 ns SPI outputs valid Slave mode e...

Страница 53: ...igure 38 shows the SPI timings in slave mode external clock Figure 38 SPI AC Timing in Slave Mode External Clock Diagram Figure 39 shows the SPI timings in master mode internal clock Figure 39 SPI AC...

Страница 54: ...ssor Hardware Specifications Rev 13 54 Freescale Semiconductor Package and Pin Listings 18 1 Package Parameters for the MPC8349EA TBGA The package parameters are provided in the following list The pac...

Страница 55: ...ensions for the MPC8349EA TBGA Figure 40 shows the mechanical dimensions and bottom surface nomenclature for the MPC8349EA 672 TBGA package Figure 40 Mechanical Dimensions and Bottom Surface Nomenclat...

Страница 56: ...K34 L33 L34 P34 R29 R30 R33 R34 T31 T32 T33 U31 U34 V31 V32 V33 V34 W33 W34 I O OVDD PCI1_C BE 3 0 J30 M31 P33 T34 I O OVDD PCI1_PAR P32 I O OVDD PCI1_FRAME M32 I O OVDD 5 PCI1_TRDY N29 I O OVDD 5 PCI...

Страница 57: ...M66EN A19 I OVDD DDR SDRAM Memory Interface MDQ 0 63 D5 A3 C3 D3 C4 B3 C2 D4 D2 E5 G2 H6 E4 F3 G4 G3 H1 J2 L6 M6 H2 K6 L2 M4 N2 P4 R2 T4 P6 P3 R1 T2 AB5 AA3 AD6 AE4 AB4 AC2 AD3 AE6 AE3 AG4 AK5 AK4 AE2...

Страница 58: ...D LDP 1 CKSTOP_IN AP22 I O OVDD LDP 2 LCS 4 AN22 I O OVDD LDP 3 LCS 5 AM22 I O OVDD LA 27 31 AK21 AP23 AN23 AP24 AK22 O OVDD LCS 0 3 AN24 AL23 AP25 AN25 O OVDD LWE 0 3 LSDDQM 0 3 LBS 0 3 AK23 AP26 AL2...

Страница 59: ...1_TGATE3 GTM2_TGATE4 D23 I O OVDD GPIO1 8 DMA_DDONE2 GTM1_TOUT3 B23 I O OVDD GPIO1 9 DMA_DREQ3 GTM1_TIN4 GTM2_TIN3 A23 I O OVDD GPIO1 10 DMA_DACK3 GTM1_TGATE4 GTM2_TGATE3 F22 I O OVDD GPIO1 11 DMA_DDO...

Страница 60: ...11_DMMD B30 I O OVDD MPH0_D4_DP DR_D12_VBUS_VLD C30 I O OVDD MPH0_D5_DM DR_D13_SESS_END A31 I O OVDD MPH0_D6_SER_RCV DR_D14 B31 I O OVDD MPH0_D7_DRVVBUS DR_D15_IDPULLUP C31 I O OVDD MPH0_NXT DR_RX_ACT...

Страница 61: ...O OVDD TSEC1_RXD 3 0 E10 A8 F10 B8 I LVDD1 TSEC1_TX_CLK D17 I OVDD TSEC1_TXD 7 4 GPIO2 27 30 A15 B15 A14 B14 I O OVDD TSEC1_TXD 3 0 A10 E11 B10 A9 O LVDD1 10 TSEC1_TX_EN B9 O LVDD1 TSEC1_TX_ER GPIO2 3...

Страница 62: ...28 AM29 I O OVDD UART_CTS 1 MSRCID4 LSRCID4 AP30 I O OVDD UART_CTS 2 MDVAL LDVAL AN30 I O OVDD UART_RTS 1 2 AP31 AM30 O OVDD I2C interface IIC1_SDA AK29 I O OVDD 2 IIC1_SCL AP32 I O OVDD 2 IIC2_SDA AN...

Страница 63: ...4 Test TEST D22 I OVDD 6 TEST_SEL AL13 I OVDD 6 PMC QUIESCE A18 O OVDD System Control PORESET C18 I OVDD HRESET B18 I O OVDD 1 SRESET D18 I O OVDD 2 Thermal Management THERM0 K32 I 8 Power and Ground...

Страница 64: ...J5 K4 K5 L4 N4 P5 R6 T6 U5 V1 W5 Y5 AA4 AB3 AC4 AD5 AF3 AG5 AH2 AH5 AH6 AJ6 AK6 AK8 AK9 AL6 Power for DDR DRAM I O voltage 2 5 V GVDD LVDD1 C9 D11 Power for three speed Ethernet 1 and for Ethernet ma...

Страница 65: ...ull up P FETs that are always enabled 5 This pin should have a weak pull up if the chip is in PCI host mode Follow the PCI specifications 6 This pin must always be tied to GND 7 This pin must always b...

Страница 66: ...ration input selects whether CLKIN or CLKIN 2 is driven out on the PCI_SYNC_OUT signal The OCCR PCICDn parameters select whether CLKIN or CLKIN 2 is driven out on the PCI_CLK_OUTn signals PCI_SYNC_OUT...

Страница 67: ...the chapter on reset clocking and initialization in the MPC8349EA Reference Manual for more information on the clock subsystem The internal ddr_clk frequency is determined by the following equation d...

Страница 68: ...2 and core_clk frequencies do not exceed their respective maximum or minimum operating frequencies The value of SCCR ENCCM SCCR USBDRCM and SCCR USBMPHCM must be programmed so that the maximum interna...

Страница 69: ...select the ratio between the primary clock input CLKIN or PCI_CLK and the internal coherent system bus clock csb_clk Table 59 and Table 60 show the expected frequency values for the CSB frequency for...

Страница 70: ...Low 0000 16 1 266 High 0010 2 1 133 High 0011 3 1 100 200 High 0100 4 1 133 266 High 0101 5 1 166 333 High 0110 6 1 200 High 0111 7 1 233 High 1000 8 1 1 CFG_CLKIN_DIV selects the ratio between CLKIN...

Страница 71: ...O divider VCO divider must be set properly so that the core VCO frequency is in the range of 800 1800 MHz Low 0110 6 1 100 150 200 Low 0111 7 1 116 175 233 Low 1000 8 1 133 200 266 Low 1001 9 1 150 22...

Страница 72: ...ore VCO frequency core frequency VCO divider The VCO divider must be set properly so that the core VCO frequency is in the range of 800 1800 MHz 0 1 2 5 6 nn 0000 n PLL bypassed PLL off csb_clk clocks...

Страница 73: ...011 33 233 350 33 233 350 33 233 350 604 0110 0000100 33 200 400 33 200 400 33 200 400 624 0110 0100100 33 200 400 33 200 400 33 200 400 803 1000 0000011 33 266 400 33 266 400 33 266 400 823 1000 0100...

Страница 74: ...input clock is CLKIN for PCI host mode or PCI_CLK for PCI agent mode Table 63 Package Thermal Characteristics for TBGA Characteristic Symbol Value Unit Notes Junction to ambient natural convection on...

Страница 75: ...e with Junction to Board Thermal Resistance The thermal performance of a device cannot be adequately predicted from the junction to ambient thermal resistance The thermal performance of any component...

Страница 76: ...ion of Junction Temperature To determine the junction temperature of the device in the application after prototypes are available use the thermal characterization parameter JT to determine the junctio...

Страница 77: ...not a standard application environment a standard heat sink is not required Table 64 shows heat sink thermal resistance for TBGA of the MPC8349EA Accurate thermal design requires thermal modeling of t...

Страница 78: ...esearch Corporation IERC 818 842 7277 413 North Moss St Burbank CA 91502 Internet www ctscorp com Millennium Electronics MEI 408 436 8770 Loroco Sites 671 East Brokaw Road San Jose CA 95112 Internet w...

Страница 79: ...ction Temperature with a Heat Sink When a heat sink is used the junction temperature is determined from a thermocouple inserted at the interface between the case of the package and the interface mater...

Страница 80: ...s of equal value are recommended over a single large value capacitor To minimize noise coupled from nearby circuits each circuit should be placed as closely as possible to the specific AVDD pin being...

Страница 81: ...DC Impedance The MPC8349EA drivers are characterized over process voltage and temperature For all buses the driver is a push pull single ended driver type open drain for I2 C To measure Z0 for the sin...

Страница 82: ...ed with the large value of the pull up pull down resistor should minimize the disruption of signal quality or speed for the output pins 21 7 Pull Up Resistor Requirements The MPC8349EA requires high r...

Страница 83: ...clature MPC nnnn e t pp aa a r Product Code Part Identifier Encryption Acceleration Temperature1 Range Package2 Processor Frequency3 Platform Frequency Revision Level MPC 8349 Blank Not included E inc...

Страница 84: ...29 and Table 31 removed the GTX_CLK125 In Table 34 updated tMDKHDX Max value from 170ns to 70ns 12 11 2010 In Table 55 added note for pin LGPL4 In Section 21 7 Pull Up Resistor Requirements updated t...

Страница 85: ...57 Operating Frequencies for TBGA in the Coherent system bus frequency csb_clk row changed the value in the 533 MHz column to 100 333 In Table 63 Suggested PLL Configurations under the subhead 33 MHz...

Страница 86: ...h level input voltage values to min 2 and max OVDD 0 3 changed low level input voltage values to min 0 3 and max 0 8 Updated DDR2 I O power values in Table 5 MPC8347EA Typical I O Power Dissipation In...

Страница 87: ...ath may occur Should Buyer purchase or use Freescale Semiconductor products for any such unintended or unauthorized application Buyer shall indemnify and hold Freescale Semiconductor and its officers...

Отзывы:

Нет отзывов

Похожие инструкции для MPC8349EA

Бренды по названию

Популярные бренды

Загрузить еще бренды