Altera Virtual JTAG IP Core Bedienungsanleitung PDF herunterladen (Seite 31)

The SLD_NODE_INFO register is used to determine the address mapping for Virtual JTAG instance in your

design. This register set is shifted out by issuing the HUB_INFO instruction. Both the ADDR bits for the SLD

hub and the HUB_INFO instruction is 0 × 0.

Because m and n are unknown at this point, the DR register (ADDR bits + VIR_VALUE) must be filled with

zeros. Shifting a sequence of 64 zeroes into the USER1 DR is sufficient to cover the most conservative case

for m and n.

HUB IP Configuration Register

When the USER1 and HUB_INFO instruction sequence is issued, the USER0 instruction must be applied to

enable the target register of the HUB_INFO instruction.

The HUB IP configuration register is shifted out using eight four-bit nibble scans of the DR register. Each

four-bit scan must pass through the UPDATE_DR state before the next four-bit scan. The 8 scans are

assembled into a 32-bit value with the definitions shown in the table below.

Table 12: Hub IP Configuration Register

Nibble

0781819262731

mALTERA_MFG_ID (0 × 06E)NHUB IP version

The dimensions of the USER1 DR chain can be determined from the SUM (m, n) and N (number of nodes

in the design). The equations below shows the values of m and n.

n = CEIL(log

(N+1))

m = SUM(m,n) – n

SLD_NODE Info Register

When the number of SLD nodes is known, the nodes on the hub can be enumerated by repeating the 8

four-bit nibble scans, once for each Node, to yield the SLD_NODE_INFO register of each node.

The DR nibble shifts are a continuation of the HUB_INFO DR shift used to shift out the Hub IP Configuration

The order of the Nodes as they are shifted out determines the ADDR values for the Nodes, beginning with,

for the first Node SLD_NODE_INFO shifted out, up to and including, for the last node on the hub. The tables

below show the SLD_NODE_INFO register and their functional descriptions.

Table 13: SLD_NODE_INFO Register

0781819262731

NODE_INST_IDNODE MFG_IDNODE IDNode Version

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Virtual JTAG Megafunction (sld_virtual_jtag)

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HUB IP Configuration Register

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2014.03.19

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Altera Virtual JTAG IP Core Bedienungsanleitung Seite 31