TMS320C6748: About "CK and ADDR_CTRL Routing Specification”

Hello Q.H, 

Thank you for the query.

Let me review the queries and update you.

Regards,

Sreenivasa

Hello Sreenivasa,

Thank you for the reply.

Kallikuppa Sreenivasa said:

Q1: Do NO.5, 6 and 7 apply when DDR2/mDDR Dual-Memory is used? Or do they also apply when Single-Memory DDR2 is used?

In this specific example, this is for T topology routing.

From the answers, I understood that NO.5 is applicable regardless of the number of DDR2s, and NO.6 and 7 are applicable when two DDR2s are used, is that correct?

Kallikuppa Sreenivasa said:

Q2:For NO.6 and 7, each signal is connected to two DDR2/mDDR. Is it correct that each Routing length must be within 100 mils?

Since this is a T topology, this is correct.

I understood.

Kallikuppa Sreenivasa said:

Q3:For NO.5, is it correct that the target signal must be kept within ±50 mils of the longest distance among the signal lines for DDR?

As i  understand this is for the CK (DDR_CLK) and ADDR_CTRL net classes nominal trace length

As for NO.5, I understand that the trace length of DDR_CLKP / DDR_CLKN and DDR_BA[2:0], DDR_A[13:0], DDR_CS, DDR_CAS, DDR_RAS, DDR_WE, DDR_CKE must be within ±50 mils of CACLM. Please let me confirm a definition of CACLM.

In the note (4), it is stated that "CACLM is the longest Manhattan distance of the CK and ADDR_CTRL net classes". This means that the trace length of the net class must be "within ±50 mils of the longest distance", and since CACLM is the longest distance, the shortest trace length in the net class should be within CACLM-50 mils, is this correct?

Best regards,
O.H

Hello Sreenivasa,

Thank you for the reply. I understood!

Best regards,
O.H