13Apr05

Directors Review Apr ’05

Status of the AFEII(-t)

AFEII proto testingAFEII (-t or final) design

Paul Rubinov and Stefano Rapisarda

PMR 213Apr05

Outline

1. Status of the AFEII prototypes testing

2. AFEII design

3. Changes from AFEII prototypes to AFEII production

PMR 313Apr05

Status of the AFEII(-t)

AFEII proto is a huge change from AFEI

Design by John Anderson/layout J Chramowicz Used existing TriP chips Changed only what had to be changed (a lot!)

remove 8 SVX/32 SIFT/8 CPLD/PIC14000add 8 FPGA/16 TriP/16

ADCs/LDOs/Flash/PIC16F

PMR 413Apr05

AFEII prototype

Key point of the AFEII is to fix the issues with AFEI by ARCHITECTURE

This WORKED. Juan’s talk shows that- the TriP/ADC/FPGA works on the AFEII prototypes.

AFEII prototype is not perfect. Many new* things worked well. Some did not.

AFEII design must change to fix what needs fixing without breaking what works.

*new here means not on AFEI

PMR 513Apr05

Status of the AFEII(-t)

AFEII proto to AFEII final is a smaller step, but still need to make changes

Things we learned from the AFEII proto Changes to accommodate TriP-t Changes to accommodate what has recently

been learned about getting the 53 Mhz readout to work

PMR 613Apr05

AFEII testing

We received 3 boards in Nov ’04 There was a lot of small stuff that

had to be addressed- part values, left/right differences, etc.

Initial boards came up ok, up to a point, then hit a snag* Worked around it but also worked on it

*programming all 8 FPGA from the flash

PMR 713Apr05

AFEII testing

Balance of proto boards, 18 Delivered March 8

The following 3 slides are from the testing plan I presented Feb 18th

The point is we are following our plan and you can see where we are

(Testing team: Kwame Bowie, Zonghan Shi, Neal Wilcer, Joshua Moua)

PMR 813Apr05

AFEII testing plan

Visual inspection Check board Check/apply FCOs Start Checklist Traveler

1st power up Check resistance between planes Check current draw

PMR 913Apr05

AFEII testing plan

Firmware loading (we have 3 different kinds of chips on these boards!) 1553 FPGA/PROM (and check JTAG chain) Helper CPLD (and all other CPLDs JTAG chain) PIC microcontroller

Functional testing 1553 tests Flash read/write FPGA power FPGA programming

PMR 1013Apr05

AFEII testing plan

Functional testing (cont) ADCs and DACs FPGA functions:

Communication Interface TriP power/communications TriP operation (charge inject)

LVDS testing “SVX” readout

PMR 1113Apr05

AFEII testing

Tests that have been done so far cover EVERY board except the three (1st article)

sacrificial lambs at DAB3 and FCC EVERY CHIP ON THE BOARD except:

VSVX (part of 53 Mhz readout)* LVDS MUX CPLDs (part of LVDS readout)

*recent studies of AFEI sequencer readout have shown there is a cross talk problem in the sequencer cable. We need to move the assignment of DVALID pin on the cable to address this issue.

PMR 1213Apr05

AFEII Testing results

All boards required some additional work after delivery

We knew this- small jobs, some deliberate, some communication/documentation problems that have since been addressed.

All boards went through a very thorough visual inspection

All boards were the same except for a very small number of issues (2)

Quality was in general very good (above what we are used to for something of this size/complexity)

PMR 1313Apr05

AFEII Testing results

3 boards sailed through testing Of the 15 remaining boards:

1 board TriP not testable- our mistake (1) Ok otherwise.

1 bad TriP, 2 possible bad TriP on 2 boards. (2) using untested TriP chips this build

3 possible bad FPGA on 2 boards (2) 4 1553 problems on 4 boards- 3 were fixed (4) 1 problem unclear (1) 3 boards waiting retest (3) 2 shorts fixed (2)

PMR 1413Apr05

AFEII Testing results

ERROR Summary 3 boards sailed through testing 3 boards fixed for known (now!)

problem (component out of tolerance)

1 we made mistake- otherwise ok 3 solder shorts (all in the area of

hand rework) 1 stuffing error 1 bad TriP, 2 probable

PMR 1513Apr05

AFEII Testing conclusion

The point of AFEII prototype testing

1. To understand how long it takes us to test boards: extrapolate from 20 to 280: can we do it in 8 weeks?A: We think this testing validates the plan, since we made it on schedule.IF THE BOARDS BASICALLY WORKwe can test 280 in 8 weeks. We can not fix a large number in 8 weeks.

2. Find some working boards!

PMR 1613Apr05

AFEII Testing conclusion

What we learned We need a large fraction of the

production build to work with little or no debugging/rework. (~50%)

We CAN fix some boards during the 8 weeks of testing- some problems are easy to find and fix (bad parts/ stuffing errors)

PMR 1713Apr05

AFEII design

Main specs of the AFEII: to exploit the full potential of TriP-t

to operate without modification to existing power infrastructure

to have same performance for VLPC bias & temp control as AFEI (but be easier to calibrate)

to readout at 53Mhz to sequencers

to provide trigger data within allowed latency time

PMR 1813Apr05

AFEII design

PMR 1913Apr05

AFEII design iteration

Functional units

MCM = 2TriP + 2ADC + FPGA + support circuits VLPC Bias and Temp control Clockgen generates all the proper clocks for

the FPGAs PIC uP and HELPER and Flash to communicate

to all the TriP, program all FPGA VSVX and Sequencer interface for L3 readout LVDS interface for trigger readout 1553 interface for slow control and monitoring Power

PMR 2013Apr05

AFEII design iteration

MCM = 2TriP + 2ADC + FPGA + support circuits

This is the heart of the board. 1st there were some routing issues

between the MCM and PIC/Helper discovered and these need to be fixed.

2nd changes are to do a better job of accommodating 53 Mhz readout.

3rd changes are to reduce power consumption and dove-tail with changes in the LVDS system.

PMR 2113Apr05

AFEII design iteration

Bias and Temp control Significant changes were made here from

the AFEI and seem to have worked perfectly.

Circuitry is precise enough but could be more accurate. Need to review the error budgets, but barring any Eureka moments, plan is to include a very simple self calibration capability. (3 precision resistors)

PMR 2213Apr05

AFEII design iteration

Clockgen We are evaluating a new part from

Lattice has become available that will make this much slicker. John A endorses making this change. This change will reduce part count.

PMR 2313Apr05

AFEII design iteration

PIC uP and HELPER

“Green wires” from AFEII proto need to be incorporated into the AFEII final board layout.

There is also a layout issue in this area (same as mentioned in the “MCM” slide)

PMR 2413Apr05

AFEII design iteration

VSVX and Sequencer interface The VSVX needs to be changed to:

1st incorporate what has been learned about 53Mhz readout recently

2nd to take better advantage of the difference between SVX chips (on AFEI) and Xilinx FPGAs (on AFEII). (get rid of the 20 inch, high speed, high load bus!)

PMR 2513Apr05

AFEII design iteration

LVDS interface Changes here are really changes in the MCM,

not the interface itself, but the are related to the LVDS system and are clearer under this heading. This change is architectural

CPLD in every slice is replaced by a small FPGA

1st this allows a much more flexible implementation of the LVDS_MUX function. The importance of this increases because of the switch to singlet track finding in the upgraded DFEs. It also helps operational issues.

2nd it makes the AFEII more homogeneous and reduces power consumption.

PMR 2613Apr05

AFEII design iteration

1553 interface The analog part of this circuit, which was

inherited from our ancient ancestors is proving to be disappointingly sensitive to part variations we are getting. However, it seems the easiest way to deal with this is to check the parts before stuffing (this is very easy). So no (further) changes are being implemented, except for one small addition for diagnostics.

PMR 2713Apr05

AFEII design iteration

Power The power dissipation of the AFEII is

quite similar to the power dissipation of the AFEI, but the detailed characteristics of the AFEII power are radically different. This is due to the volatile nature of the FPGA vs. static nature of the CPLDs.

The power distribution system on the AFEII prototypes is a success. The plan is to slightly rearrange which chips get power from which voltage tap, to better match the distribution of power available, but no other changes. I judge the risk of introducing noise by use of DC-DC converters too high at this point.

PMR 2813Apr05

AFEII design conclusion

The critical thing for the success of this project is SCHEDULE

The critical thing for the success of the schedule is a WORKING DESIGN which requires little debugging/fixing

PMR 2913Apr05

AFEII design conclusion

The plan for getting this done is: Implement known fixes on schematic

(now)

Consider proposed changes (by early May)

Finish implementing reasonable changes (by late May)