Blocking Allowed Mode, Destination Node Blocked a | Atmel SpW-10X

	SpW-10X	Ref.:	UoD_SpW-10X_
	SpaceWire Router		UserManual
	SpaceWire Router	Issue:	3.4
	User Manual	Issue:	3.4
	User Manual	Date:	11th July 2008

In blocking allowed mode the network path is blocked until the destination node starts to accept data again. Packets waiting to use the network path will wait indefinitely.

In watchdog timer mode the router will timeout and the network path will be cleared so other packets can use the path.

Blocking Allowed Mode

What happens when Blocking Allowed mode is being used and a destination node becomes blocked is illustrated in Figure 8-14 to Figure 8-16. In this example two routing switches, R1 and R2, are connected to form a network and only SpaceWire ports 1 to 6 are shown for clarity.

a)A packet arrives at port 3 of routing switch R1 destined for port 4 and then port 5 of R2 (as shown by the path address 4, 5 at the head of the packet.

			1		4
			1		4
			2	R1	5
			2	R1	5
			3		6
	5	4
	5	4

(a)

14

2 R2 5

36

Figure 8-14 Destination Node Blocked (a)

b)The packet is routed towards its destination but during packet transfer the destination stalls and does not accept any more data. The network path is blocked and the packet waiting at R1 port 2 is also blocked

			1		4
			1		4
			2	R1	5
	4	4	2	R1	5
			3		6
			3		6

1

4

2

R2

5

36

(b)

Figure 8-15 Destination Node Blocked (b)

c)The path between routing switch R1 port 4 and routing switch R2 port 1 is now blocked. While the first packet is routed another packet arrives at port 2 on router R1 with destination port 4 on router R1 and destination port 4 on router R2. The packet must wait as the ports are currently busy and can only be routed if the downstream node starts receiving data again.

Preliminary

96

Image 96

Atmel SpW-10X user manual Blocking Allowed Mode, Destination Node Blocked a

Contents

Issue Date Th July UoDSpW-10XUserManual Date Issue Comments Author Ref. UoDSpW-10X11th July SpW-10X Contents Control Logic and Operational Modes Global Spacewire Link Control 103 128 136138 143 150151 15.16 List of Figures 100 List of Tables Able 9-7 E Xternal P ORT C ONTROL/S Tatus F Ields Introduction TERMS, Acronyms and Abbreviations Documents Ref. UoDSpW-10X UserManualDate 11th July Applicable Documents Document Number Document Title User Applications STAND-ALONE Router Node Interface Embedded Router Issue Date 11th July Expanding the Number of Router Ports Expanding the number of SpaceWire Ports SpW-10X Functional Overview Spacewire Ports External Ports Configuration Port Routing TableRouting Control Logic and Crossbar TIME-CODE Processing CONTROL/STATUS Registers Pin Signal Type Description PIN Locations VSSA2 GND PFOLVDS33Z EXTOUTDATA90 PO44F EXTOUTDATA108 PO44F EXTTIMEOUT6 PO44F Global Signals Device Interface Spacewire Signals SpW-10X SpaceWire SignalsTestIOEn TestEn DOUTMinus1 DOUTPlus2DOUTMinus2 DOUTPlus3 11th July DINPlus1 DINMinus1DINPlus2 DINMinus2 SpaceWire Input Fail Safe Resistors Lvds Receiver Fail-Safe Resistors SpW-10X External Port Data Signals UserManual Issue Date 11th JulyExternal Port Interface Signals PinNo Dir Description Type EXT9INDATA5 TIME-CODE Signals Time-Code Signals PinNo Dir Description TypeSelexttime and the EXTTIMEIN70 Exttickin the value on EXTTIMEIN70 is EXTTIMEIN70 inputExttickout is asserted Status Interface Signals Link error indication Signals PinNo Dir Description TypePower on Configuration Normal Operation Reset Configuration Signals Configuration interface timing specification 11th July Reset Configuration Signals Dir Description Feedbdiv at resetMaps to PORTXRATE20 Maps to Porstartonreqn POWER, GROUND, PLL and Lvds Signals GeneralDecoupling Lvds Reference PLL with external components Interface Operations External Port Interface Operation External port read timing specification TIME-CODE Interface Operation Status Interface Operation Time-Code Output Interface Status Output Bits Reset Configuration Interface Operation Reset configuration interface timing specification Spacewire Router Packet Types Packet Addresses Packet Priority Packet Header DeletionPacket Priority Mapping Packet Address Physical Port type Invalid Addresses Command Packets Supported CommandsData Packets Read Command Issue Date Th July Read Single Address Characteristics Read Single Address Command Format SpW-10X EOP Read Incrementing Command Issue Date Th July Read Incrementing Address Characteristics Data Length MS 11th July 00h Read Modify Write Command 11 Read-Modify-Write Command Characteristics Preliminary66 RMW Read-Modify-Write example operation FEh 00h Write Command 14 Write Command Characteristics FEh 01h CRC MSB Command Error Response StatusCode SpW-10X Command Packet Cyclic Redundancy Check Local Source Path Address Source Path Address Field Command Packet Fill Bytes Date 11 th July Spacewire Link Control Default operating modeControl Logic and Operational Modes Auto-Start Link-Disable Automatic deactivate driver mode Deactivate driver operating mode Setting the SpaceWire port transmit data rate Txrate +1 Setting SpaceWire Transmit Data Rate TX 10MbitDIV +1 Global Spacewire Link Control Start on request mode Disable on Silence modeCfgstartonreq bit Packet address error Control Logic and RoutingArbitration Arbitration of packets with matching priority Arbitration of three packets with matching priority Arbitration of packets with different priority SpW-10X SpW-10X Group Adaptive Routing 10 Normal group adaptive routing 11 Group adaptive routing when other ports busy Loop-back with Self-Addressing 13 Packet Self-Addressing mode Packet Blocking Blocked destination Blocking Allowed Mode 14 Destination Node Blocked a 16 Destination Node Blocked c Watchdog timer mode 19 Destination Node Blocked Watchdog Mode c Blocking Allowed 21 Source Node Stalled a 100 101 102 Register Definitions Internal Memory MAP Register Addresses Summary 11th July Configuration Register Addresses Group Adaptive Routing Table Registers 106 Issue Date Th July GAR Table Register Description Bits Name Reset Description Read/Write Value Configuration Port Control/Status Register Fields Port CONTROL/STATUS RegistersGeneric port control/status register fields Configuration port control/status register fields 11th July Bits Name Reset Description Read/Write Value 110 111 SpaceWire port control/status register bits SpaceWire Port Control/Status Register Fields 113 114 External port control/status register bits Router CONTROL/STATUS RegistersNetwork Discovery Register Router Identity Register Router Control Register Router Control Register Fields 118 119 Error active Register Error Active Register Fields Time-Code Register Time-Code Register Fields Device Manufacturer and Chip ID Register Time-Code Enable Register General Purpose Register Transmit Clock Control Register 125 126 Destination Key Register Unused Registers and Register BitsEmpty packets Writing to a READ-ONLY Register Switching Characteristics Clock and Reset Timing ParametersSerial Signals Timing Parameters External Port Timing Parameters External port input Fifo timing parameters TIME-CODE Interface Timing Parameters ERROR/STATUS Interface Timing Parameters Time-code Timectrrst interface 132 Switching Latency Latency and JitterClock Periods Router Latency Issue Date Th July SpaceWire port to SpaceWire port SpaceWire port to External portExternal port to SpaceWire port Time-code Latency Time-code Jitter 10.6.6 200M bits/s Input and Output Bit Rate Example Electrical Characteristics DC CharacteristicsOperating Conditions Symbol Description Value Units Absolute Maximum Ratings Symbol Description Value Units Absolute Maximum RatingsReliability Information Reliabilty Information Example Circuit Diagram Application Guidelines 139 PCB Design and Layout Guidelines Status / Power On Configuration Interface External PortsTime-code Interface 12.2.10 PLL PLL Layout Recommendations Anomalies and Warnings Anomalies 144 Reset Anomaly Data Strobe Reset Waveform 146 Data Strobe Disable Waveform Reset Anomaly Workarounds Parity Error Anomaly Parity Error ActionParity Error Anomaly Parity Error Workaround No error end of packet inserted after parity error Technical Support Issue 3.3 to Issue Issue 3.2 to IssueIssue 3.1 to Issue Document Changes Issue 3.0 to Issue Issue 2.5 to Issue Issue 2.4 to Issue Issue 2.3 to IssueIssue 2.2 to Issue Issue 2.1 to Issue Issue 2.0 to IssueIssue 1.7 to Issue Issue 1.6 to Issue Issue 1.1 to Issue Issue 1.0 to Issue