jtag on can with lmb
DESCRIPTION
JTAG on CAN with LMB. Estimation of time for JTAG/CAN conversion and propagation using the ATLAS/DCS LMB. Present CAN Bus system. 2 PCs, Win98 and Linux 3 CAN nodes Node with PCI I/F Node with VME I/F Local Monitor Box - PowerPoint PPT PresentationTRANSCRIPT
C.Fukunaga/TGC electronics meeting at CERN Feb.,11,2000
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JTAG on CAN with LMB
Estimation of time for JTAG/CAN conversion and propagation using
the ATLAS/DCS LMB
C.Fukunaga/TGC electronics meeting at CERN Feb.,11,2000
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Present CAN Bus system • 2 PCs, Win98 and Linux• 3 CAN nodes
– Node with PCI I/F– Node with VME I/F– Local Monitor Box
• Operation of LMB from both side confirmed with DCS stndrd AVR software
• Our ultimate goal is to control the TTC with JTAG via CAN, but presently no TTC connection has been achieved.
C.Fukunaga/TGC electronics meeting at CERN Feb.,11,2000
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Structure of LMB
• Two processors of ATMEL• AVR AT90S2313-10 10MHz,1Kbytes• AVR AT90S1200-12 12MHz
• CAN Bus driver and controller
C.Fukunaga/TGC electronics meeting at CERN Feb.,11,2000
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How to make JTAG with LMB
• With CS = 0, Serial I/F of Can controller is used to input/output CAN data.
• With CS = 1, SCLK,SDI,SDO with CSADC of PortD are used for JTAG lines.
C.Fukunaga/TGC electronics meeting at CERN Feb.,11,2000
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C.Fukunaga/TGC electronics meeting at CERN Feb.,11,2000
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CAN JTAG conversion 1
• Put desired TMS,TDI sequence of JTAG into a CAN packet
• In a packet total 32 steps of both TMS and TDI are stored.
CAN packet 8bytes TMS TDI
32 TMS sequence 32 TDI sequence
TMS
TDI
C.Fukunaga/TGC electronics meeting at CERN Feb.,11,2000
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CAN JTAG conversion 2
• Results (see another slide for execution)– Program size 226 bytes– Data size 12 bytes– 5041 Cycle counts – 504.1sec/32 TMS instruction(=1 CAN pac
ket)• LMB proc. takes 15.8msec. for 1000
TMS instructions.
C.Fukunaga/TGC electronics meeting at CERN Feb.,11,2000
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C.Fukunaga/TGC electronics meeting at CERN Feb.,11,2000
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CAN Bus network 1
• For JTAG 32TMS operation, we need two packets(Tx and Rx) and an extra packet for end flag.
• The time consumption will be increased lineary with number of TMS operations.
• The time consumption of the network access is serious than CAN/JTAG conversion proc.
C.Fukunaga/TGC electronics meeting at CERN Feb.,11,2000
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CAN Bus network 2
• Transfer Speed over the simplest CAN bus (1 to 1) with the TMS bit length (CAN bus 125Kbaud)
• Rate=16.36KTMS/s
C.Fukunaga/TGC electronics meeting at CERN Feb.,11,2000
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CAN Bus network 3
• Transfer Rate versus Various CAN baud setting:
• For large scale CAN bus, baud rate 125K is recommended
C.Fukunaga/TGC electronics meeting at CERN Feb.,11,2000
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(Rough) Estimation for Total system
• Assume total 500TMS/patch panel, and CAN baudrate 125Kbit/s.
• It takes at least 31ms for one patch panel.• Since CAN is in principle 1 to 1 connectio
n, we must multiply 12 for duration of 1 PS pack --> 372ms(0.37s)
• Thus if we have 100 PS pack, it will take 37s for JTAG initialization.