atlas dcs atlas dcs elmb prr, 4 mar 2002, h.boterenbrood 1 software for the elmb henk boterenbrood...

ATLAS

DCS

ATLAS DCS ELMB PRR, 4 Mar 2002, H.Boterenbrood 1

Softwarefor the ELMB

Henk Boterenbrood

ATLAS DCS

ATLAS

DCS


Outline

• ELMB Applications• Implementation: ELMBio• Measures against Radiation Effects• Plans for new Features and Upgrades• Conclusion

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ELMB Applications

• Envisage many different monitoring & control applications Limited only by processing power and resources

(Flash, RAM, I/O)• Common software features/requirements

CANopen communication In-System-Programming via CAN-bus Measures to counter effects of SEU Configuration storage in EEPROM (incl. CRC) Low-level control of on-board devices (ADC, CAN) C, using a commercial development toolset

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• General-purpose no specific I/O processing or features

• Demonstrator, example, framework Ready-to-use (with ‘Motherboard’) Binary, source code and documentation on the web

• I/O 64 analog inputs (16-bits) 64 analog outputs (12-bits, requires external ELMB-DAC

module) 8 to 16 digital inputs 8 to 16 digital outputs

ELMBio Application Firmware (1)

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• Communication: CANopen Object Dictionary reading and writing using SDO

messages(Service Data Object)

I/O-data communication using PDO messages (Process Data Object) configurable: triggered by: SYNC, timer, Change-of-State

Network management (node ‘state’) Lifeguarding, Nodeguarding, Heartbeat


(underlined: CANopen message types and services)

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• Other features Configuration options (e.g ADC, Comm, etc.; in

the Object Dictionary) Configuration/parameter storage in non-volatile

memory (EEPROM)

Different application configurations possible using compile options

• for on-chip ADC• some rad-tolerant features• motherboards

To be used with ‘Slave’ processor application(also provided)

• Watchdog• In-System-Programming-via-CAN-bus

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Radiation Effects: SEU (1)

Single Event Upset (SEU ‘bit flip’)

• Flash memory (program code)appears to be unaffected

• EEPROM storage (configuration)appears to be unaffected

• RAM and registers (CPU, devices)are all affected by SEUs

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Radiation Effects: SEU (2)

SEE test at Louvain-la-Neuve very useful !• Standard ELMBio application

with extensions doing memory checks (every 5 s) Flash (program code CRC, pattern in unused space) EEPROM, RAM (patterns in unused space) CAN (unused registers), ADC (regs with known values)

• …but also: application ‘misbehaving’, crashes… There is (almost) always some explanation !

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Anti-SEU Measures in Software (1)

• Refresh of RAM and register content Global variables (configuration)

• re-read from EEPROM before every use (option)

Microcontroller I/O-ports and Data-Direction Registers• periodic refresh (value from flash)

CAN-controller• message descriptor refresh when reading/writing message buffer

(option)• reset (full config refresh) at Lifeguarding time-out• other problems detected by host and resolved e.g. by soft/hard reset

ADC• configuration refresh before each channel scan (value from EEPROM &

flash)• full reset/recalibration/configuration refresh before each channel scan

(configurable)

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• Other… Dummy handlers installed for unused interrupts

(in case of spurious interrupts; remove source of interrupt if any)

Explicitly check for 0-or-1 for ‘boolean’ variables(instead of =0 or 0)

Mask an index with maximum size, when known CRC checksums

• on parameter storage in EEPROM• on program code in Flash

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• 2nd ELMB (‘Slave’) processor with dedicated task Watchdog

• periodic ‘interrupt’ from Master to Slave, or else…• non-functioning Slave is reported by Master

In-System-Programming via CAN-bus• Master program reload or upgrade (or Slave)• using CANopen ( does not interfere with other CAN

comm!)• …but not during radiation

(made possible thanks to the ingeneous way in which the 2 processorson the ELMB are integrated, combined with some clever software !)

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• ADC periodic sampling Channel upper and lower limit (window) check

• Scanning period, global enable (EEPROM)• Limits per analog input channel (EEPROM)• (Async) data transfer only in case of over/underlimit

(crossing?)

Delta change (more SEU sensitive)• Scanning period, global enable (EEPROM)• Delta per analog input channel (or one Delta for all chans?)

(EEPROM)• (Async) data transfer only in case of a delta

increase/decrease

Standard ADC read-out still possible !

New Features Planned (1)

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• ADC calibration Purpose: ADC read-out returns voltage values

instead of raw ADC counts Need to determine offset/gain Permanent storage of calibration values onboard

(EEPROM), also offline?

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• DAC Optionally (initial) DAC settings stored in EEPROM

• set at power-up

Optional periodic DAC output value refresh(EEPROM, anti-SEU, if radiation tests show DAC can be used !);in combination with ADC feedback ?

Set a 4-20 mA current output directly, e.g. using a A valuein the CAN-message (ELMB does the conversion to a DAC value)

Ramping function, e.g. to control a HV-supply• End value and ramping speed

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• CANMessage read-out under interrupt (and message buffer in RAM), because… ADC or DAC operations are slow due to low-power

opto-couplers used and… async periodic ADC/DAC operations may cause

message loss when a host sends multiple messages ofthe same ‘type’ (currently CAN-controller acts as aone-message/type buffer)

(CAN-controller interrupt line now used in Master/Slave watchdog function sw adjustment)

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Conclusion

• Users of the general-purpose application (ELMBio) use as-is (flexibility: CANopen configuration, compile-time options)

further development on-going functionality may be added on request

• Developers of custom applications can/should use the general-purpose app as a framework if required, should apply anti-SEU measures where possible must use CANopen must use Slave app for 2nd processor

(and add appropriate functionality to the Master app)

atlas dcs atlas dcs elmb prr, 4 mar 2002, h.boterenbrood 1 software for the elmb henk boterenbrood...

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