NWK954
Expansion Port (Continued)
Signal | Pin no. | Type | Description |
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BPACTIN_N7 | 89 | Digital input, | Backplane activity inputs. Indicate activity on up to 7 |
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BPACTIN_N6 | 90 | no | other hubs connected to the backplane. Received from the |
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BPACTIN_N5 | 91 |
| backplane via external receivers. Each NWK954 |
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BPACTIN_N4 | 92 |
| connected to the local expansion bus receives all of these |
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BPACTIN_N3 | 101 |
| backplane activity inputs. Unused inputs must be pulled |
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BPACTIN_N2 | 102 |
| high or connected directly to DIGVDD. Inputs are sampled |
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BPACTIN_N1 | 103 |
| on the rising edge of TXCLKIN. |
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BPDIE_N | 107 | Standard digital | Backplane data input enable. Enables the external |
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| output and digital | receivers that pass backplane data and clock onto the local |
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| input with | IRD[4:0] and BPCLK lines. Only one of the local NWK954s |
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| is required to drive this signal, the others should be left |
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| unconnected. This signal changes asynchronously. |
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| Polarity defaults to active low but may be switched to |
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| active high by adding an external 10kΩ |
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BPDOE_N | 108 | Standard digital | Backplane data output enable. Enables the external |
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| output and digital | drivers that pass the local IRD[4:0] and BPCLK signals |
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| input with | onto the backplane. Output changes on the rising edge of |
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| TXCLKIN. Only one of the local NWK954s is required to drive |
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| this signal, the others should be left unconnected. Polarity |
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| defaults to active low but may be switched to active high by |
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| adding an external 10kΩ |
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BPCLK | 96 | High drive open | 25MHz backplane clock. Data transitions on IRD[4:0] are |
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| drain digital output | synchronised to this clock. When another hub in the stack |
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| and digital input | is sourcing data, this clock is received from the backplane |
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| with | to all local NWK954s through an external receiver. When a |
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| local NWK954 is sourcing data, BPCLK is supplied to the |
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| backplane through an external driver. Requires external |
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BPCOL_N | 95 | High drive open | Backplane collision. This signal may be driven by any of |
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| drain digital output | the local NWK954s to indicate that a collision has been |
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| and digital input | detected, and is supplied to the backplane through an |
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| with | external driver. Output transitions are synchronous to |
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| the rising edge of TXCLKIN and the input is sampled on the |
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| rising edge of TXCLKIN. Requires external |
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| operation. |
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BPCOLIN_N | 104 | Digital input, | Backplane collision input. Indicates that a collision has |
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| no | been detected by any hub in the stack. Received from the |
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| backplane via an external receiver. Connects to all local |
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| NWK954s. Must be pulled high or connected directly to |
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| DIGVDD if not used. Input is sampled on the falling edge of |
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| TXCLKIN. |
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BPCOLOE_N | 106 | Standard digital | Backplane collision output enable. Enables the external |
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| output and digital | driver that passes BPCOL_N onto the backplane. Only one |
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| input with | of the local NWK954s is required to drive this signal, the |
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| others should be left unconnected. Output changes on the |
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| rising edge of TXCLKIN. Polarity defaults to active low but |
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| may be switched to active high by adding an external 10kΩ |
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| . |
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| Table 5 (continued) |
10