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Hi Venkat, The entry into the SEND_BEACON state is not synchronized to the PCS symbol_timer (MII TX_CLK). Therefore, the beacon_timer may be started and tx_cmd set to BEACON asynchronously to the PCS symbol_timer. By expanding the beacon timer to
22 Bit Times, one is guaranteed to always get five expirations of the symbol_timer within the 22 Bit Time period of the beacon_timer. If beacon_timer was left at 20 Bit Times, then the only time one would transmit 5 BEACON symbols would be when beacon_timer was started exactly when the symbol_timer, but such a synchronous relationship is not specified. Regards, Tim From: Venkatraman Iyer <Venkat.Iyer@xxxxxxxxxxxxx>
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Hi, Since the BEACON request is conveyed on MII which is a symbol interface, does changing the beacon timer from 20 to 22 bit times mean that only part of the symbol is transmitted? Venkat Iyer 512 427 0253 (office) 512 264 5215 (mobile) From: Piergiorgio Beruto <piergiorgio.beruto@xxxxxxxxxxxxxx>
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Hello again, First, I would like to thank all the people that worked and are still working offline to check and validate this issue, including (but not limited to) Gergely and Mr. Yong Kim. After collecting some more feedback, I wish to post the latest resolution that I am going to propose in Milwaukee. This one also better clarifies how to synchronize the internal variables with the MII transmit clock. Besides, it fixes a couple of editorial issues. Kind Regards, Piergiorgio ----- FULL TEXT OF THE PROPOSED RESOLUTION ----- PROPOSED ACCEPT IN PRINCIPLE. [1] In Figure 148-4, in the HOLD state, replace " TX_ER <= plca_txer TXD <= 0000 " with " TX_ER <= ENCODE_TXER(tx_cmd_sync) TXD <= ENCODE_TXD(tx_cmd_sync) " [2] In Figure 148-4, in the ABORT state, replace " TX_ER <= plca_txer TXD <= 0000 " with " TX_ER <= ENCODE_TXER(tx_cmd_sync) TXD <= ENCODE_TXD(tx_cmd_sync) " [3] In Figure 148-4, in both the COLLIDE and DELAY_PENDING states add the following: " TX_ER <= ENCODE_TXER(tx_cmd_sync) TXD <= ENCODE_TXD(tx_cmd_sync) " [4] In Figure 148-4, add a recirculating arc with an "ELSE" condition to the following state boxes: WAIT_MAC, PENDING, DELAY_PENDING, COLLIDE and ABORT. [5] In Figure 148-4, in the transition from WAIT_MAC to TRANSMIT state, change the condition from "plca_txen" to "MCD * plca_txen" [6] At page 242, line 44, change the duration of the beacon_timer from "20 bit times" to "22 bit times". [RATIONALE] this is required so that the BEACON duration is guaranteed to be always the same (20 bit times) despite the timer tolerance vs the MII TX_CLK tolerance which drives the PLCA DATA State Diagram. [7] At page 248, line 8 remove the duplicate MCD declaration (the correct definition is at line 50 in the Abbreviations section). [8] At page 248, line 34 change "A continuous free-running timer that shall expire synchronously with the falling edge of TX_TCLK."
with "A continuous free-running timer that shall expire synchronously with the falling edge of the MII TX_CLK" [9] Add the following variable definition in 148.4.6.2: " tx_cmd_sync The value of the tx_cmd variable sampled on the rising edge of the MII TX_CLK. Values: see tx_cmd in 148.4.5.2" [10] In Figure 148-4, replace all occurrances of "ENCODE_TXD(tx_cmd)" with "ENCODE_TXD(tx_cmd_sync)" [11] In Figure 148-4, replace all occurrances of "ENCODE_TXER(tx_cmd)" with "ENCODE_TXER(tx_cmd_sync)" ----------- From: Piergiorgio Beruto <piergiorgio.beruto@xxxxxxxxxxxxxx>
Hello 802.3cg, Thanks to some of you working offline, we’ve found a regression in the PLCA DATA State Diagram caused by comment i-373 on D3.0. The intention of i-373 resolution was to clarify the behaviour of the State Diagram without changing the functionality. In the process, despite our best effort, we’ve missed some important changes that broke the DATA State Diagram function.
Please find attached to this e-mail the proposed changes meant to accomplish the original intention of i-373. Any feedback would be much appreciated. Kind Regards, -- Piergiorgio Beruto Senior System Designer Canova Tech Srl. "The Art of Silicon Sculpting" Via Magliotto 2, Campus Savona, Palazzina Branca 17100 Savona (SV), Italy Phone: +39 049 7811065 ext. 265 GSM: +39 333 6333289 Skype: canovatech_pb To unsubscribe from the STDS-802-3-10SPE list, click the following link:
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