数据搜索系统,热门电子元器件搜索 |
|
DP83869HM 数据表(PDF) 40 Page - Texas Instruments |
|
|
DP83869HM 数据表(HTML) 40 Page - Texas Instruments |
40 / 138 page 40 DP83869HM SNLS614 – SEPTEMBER 2018 www.ti.com Product Folder Links: DP83869HM Submit Documentation Feedback Copyright © 2018, Texas Instruments Incorporated 9.4.10.6 Restart Auto-Negotiation If a link is established by successful Auto-Negotiation and then lost, the Auto-Negotiation process resumes to determine the configuration for the link. This function ensures that a link can be re-established if the cable becomes disconnected and reconnected. After Auto-Negotiation is completed, it may be restarted at any time by writing 1 to bit 9 of the BMCR (register address 0x0000). A restart Auto-Negotiation request from any entity, such as a management agent, causes DP83869HM to halt data transmission or link pulse activity until the break_link_timer expires. Consequently, the Link Partner goes into link fail mode and the resume Auto- Negotiation. The DP83869HM resumes Auto-Negotiation after the break_link_timer has expired by transmitting FLP (Fast Link Pulse) bursts. 9.4.10.7 Enabling Auto-Negotiation Through Software If Auto-Negotiation is disabled by MDIO access, and the user desires to restart Auto-Negotiation, this could be accomplished by software access. Bit 12 of BMCR (register address 0x00) should be cleared and then set for Auto-Negotiation operation to take place. If Auto-Negotiation is disabled by strap option, Auto-Negotiation can not be reenabled. 9.4.10.8 Auto-Negotiation Complete Time Parallel detection and Auto-Negotiation typically take 2-3 seconds to complete. In addition, Auto-Negotiation with next page exchange takes approximately 2-3 seconds to complete, depending on the number of next pages exchanged. Refer to Clause 28 of the IEEE 802.3 standard for a full description of the individual timers related to Auto-Negotiation. 9.4.10.9 Auto-MDIX Resolution The DP83869HM can determine if a straight or crossover cable is used to connect to the link partner. It can automatically re-assign channel A and B to establish link with the link partner, (and channel C and D in 1000BASE-T mode). Auto-MDIX resolution precedes the actual Auto-Negotiation process that involves exchange of FLPs to advertise capabilities. Automatic MDI/MDIX is described in IEEE 802.3 Clause 40, section 40.8.2. It is not a required implementation for 10BASE-Te and 100BASE-TX. Auto-MDIX can be enabled or disabled by strap, using the AMDIX Disable strap, or by register configuration, using bit 6 of the PHYCR register (address 0x0010). When Auto-MDIX is disabled, the PMA is forced to either MDI (straight) or MDIX (crossed). Manual configuration of MDI or MDIX can also be accomplished by strap, using the Force MDI/X strap, or by register configuration, using bit 5 of the PHYCR register. For 10/100, Auto-MDIX is independent of Auto-Negotiation. Auto-MDIX works in both Auto-Negotiation mode and manual forced speed mode. 9.5 Programming 9.5.1 Strap Configuration The DP83869HM uses many of the functional pins as strap options to place the device into specific modes of operation. The values of these pins are sampled at power up or hard reset. During software resets, the strap options are internally reloaded from the values sampled at power up or hard reset. The strap option pin assignments are defined below. Configuration of the device may be done through the strap pins or through the management register interface. A pullup resistor and/or a pulldown resistor of suggested values may be used to set the voltage ratio of the strap pin input and the supply to select one of the possible selected modes. The MAC interface pins must support I/O voltages of 3.3 V, 2.5 V, and 1.8 V. As the strap inputs are implemented on these pins, the straps must also support operation at 3.3-V, 2.5-V, and 1.8-V supplies depending on what voltage was selected for I/O. RX_D0 and RX_D1 pins are 4 level strap pins. All other strap pins have two levels. |
类似零件编号 - DP83869HM |
|
类似说明 - DP83869HM |
|
|
链接网址 |
隐私政策 |
ALLDATASHEETCN.COM |
ALLDATASHEET是否为您带来帮助? [ DONATE ] |
关于 Alldatasheet | 广告服务 | 联系我们 | 隐私政策 | 链接交换 | 制造商名单 All Rights Reserved©Alldatasheet.com |
Russian : Alldatasheetru.com | Korean : Alldatasheet.co.kr | Spanish : Alldatasheet.es | French : Alldatasheet.fr | Italian : Alldatasheetit.com Portuguese : Alldatasheetpt.com | Polish : Alldatasheet.pl | Vietnamese : Alldatasheet.vn Indian : Alldatasheet.in | Mexican : Alldatasheet.com.mx | British : Alldatasheet.co.uk | New Zealand : Alldatasheet.co.nz |
Family Site : ic2ic.com |
icmetro.com |