C.Fukunaga/TGC electronics meeting at CERN Feb.,11,2000

1

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

2

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

3

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

4

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

5

C.Fukunaga/TGC electronics meeting at CERN Feb.,11,2000

6

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

7

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

8

C.Fukunaga/TGC electronics meeting at CERN Feb.,11,2000

9

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

10

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

11

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

12

(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.