diff --git a/algo/CMakeLists.txt b/algo/CMakeLists.txt
index b7d83336ca0b9830ac92c5ebc693e474bbc23521..4a93e43c2060cba0a9f7b206dc2bb6bd287b83f5 100644
--- a/algo/CMakeLists.txt
+++ b/algo/CMakeLists.txt
@@ -6,6 +6,7 @@ add_subdirectory (test)
set(SRCS
evbuild/EventBuilder.cxx
trigger/TimeClusterTrigger.cxx
+ detectors/sts/UnpackSts.cxx
)
add_library(Algo SHARED ${SRCS})
diff --git a/algo/detectors/sts/UnpackSts.cxx b/algo/detectors/sts/UnpackSts.cxx
new file mode 100644
index 0000000000000000000000000000000000000000..00c66eaddde4bb059c51a5588124a768b547383e
--- /dev/null
+++ b/algo/detectors/sts/UnpackSts.cxx
@@ -0,0 +1,132 @@
+/* Copyright (C) 2021 GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt
+ SPDX-License-Identifier: GPL-3.0-only
+ Authors: Pierre-Alain Loizeau, Volker Friese [committer] */
+
+#include "UnpackSts.h"
+
+#include <cassert>
+#include <vector>
+
+#include <cmath>
+
+#include "StsXyterMessage.h"
+
+using std::vector;
+
+namespace cbm::algo
+{
+
+ // ---- Algorithm execution ---------------------------------------------
+ vector<CbmStsDigi> UnpackSts::operator()(const uint8_t* msContent, const fles::MicrosliceDescriptor& msDescr,
+ const uint64_t tTimeslice)
+ {
+
+ // --- Assert that parameters are set
+ assert(fParams);
+ fCurrentTsTime = tTimeslice;
+
+ // --- Output vector
+ vector<CbmStsDigi> digiVec;
+
+ // --- Current TS_MSB epoch cycle
+ auto msTime = msDescr.idx; // Unix time of MS in ns
+ fCurrentCycle = std::ldiv(msTime, fCycleLength).quot;
+
+ // --- Get first TS_MSB (first message in microslice must be of type ts_msb)
+ const stsxyter::Message firstMessage(msContent[0]);
+ assert(firstMessage.GetMessType() == stsxyter::MessType::TsMsb);
+ ProcessTsmsbMessage(firstMessage);
+
+ // ---Â Number of messages in microslice
+ auto msSize = msDescr.size;
+ assert(msSize % sizeof(stsxyter::Message) == 0);
+ const uint32_t numMessages = msSize / sizeof(stsxyter::Message);
+
+ // --- Message loop
+ for (uint32_t messageNr = 1; messageNr < numMessages; messageNr++) {
+
+ // --- Cast MS content to STSXYTER message
+ const stsxyter::Message message(msContent[messageNr]);
+ const stsxyter::MessType type = message.GetMessType();
+
+ // --- Action depending on message type
+ switch (type) {
+
+ case stsxyter::MessType::Hit: {
+ ProcessHitMessage(message, digiVec);
+ break;
+ }
+ case stsxyter::MessType::TsMsb: {
+ ProcessTsmsbMessage(message);
+ break;
+ }
+ default: {
+ break;
+ }
+
+ } //? Message type
+
+ } //# Messages
+
+ return digiVec;
+ }
+ // --------------------------------------------------------------------------
+
+
+ // ----- Process hit message --------------------------------------------
+ void UnpackSts::ProcessHitMessage(const stsxyter::Message& message, vector<CbmStsDigi>& digiVec) const
+ {
+
+ uint16_t elink = message.GetLinkIndexHitBinning();
+ const UnpackStsElinkPar& elinkPar = fParams->GetElinkPar(elink);
+ uint32_t asicNr = elinkPar.fAsicNr;
+ uint32_t numChansPerModule = fParams->fNumAsicsPerModule * fParams->fNumChansPerAsic;
+
+ // --- Hardware-to-software address
+ uint32_t address = elinkPar.fAddress;
+ uint32_t channel = 0;
+ if (asicNr < fParams->fNumAsicsPerModule / 2) { // front side (n side)
+ channel = message.GetHitChannel() + fParams->fNumChansPerAsic * asicNr;
+ }
+ else { // back side (p side)
+ channel = numChansPerModule - message.GetHitChannel() + 1;
+ }
+
+ // --- Time stamp
+ // --- Expand to full Unix time in clock cycles
+ uint64_t timeCC = message.GetHitTimeBinning() + fCurrentEpochTime;
+ // --- Convert time into ns
+ assert(timeCC >> 59 == 0); // avoid overflow in 64 bit
+ uint64_t timeNs = (timeCC * fParams->fClockCycleNom) / fParams->fClockCycleDen;
+ // --- Correct ASIC-wise offsets
+ timeNs -= elinkPar.fTimeOffset;
+ // --- Calculate time relative to timeslice
+ timeNs -= fCurrentTsTime;
+ // --- TODO: Add walk correction (depends on ADC)
+
+ // --- Charge
+ double charge = elinkPar.fAdcOffset + (message.GetHitAdc() - 1) * elinkPar.fAdcGain;
+
+ // --- Create output digi
+ digiVec.emplace_back(address, channel, timeNs, charge);
+ }
+ // --------------------------------------------------------------------------
+
+
+ // ----- Process an epoch (TS_MSB) message ------------------------------
+ void UnpackSts::ProcessTsmsbMessage(const stsxyter::Message& message)
+ {
+
+ auto epoch = message.GetTsMsbValBinning();
+
+ // --- Cycle wrap
+ if (epoch < fCurrentEpoch) fCurrentCycle++;
+
+ // --- Update current epoch
+ fCurrentEpoch = epoch;
+ fCurrentEpochTime = (fCurrentCycle * fParams->fEpochsPerCycle + epoch) * fParams->fEpochLength;
+ }
+ // --------------------------------------------------------------------------
+
+
+} /* namespace cbm::algo */
diff --git a/algo/detectors/sts/UnpackSts.h b/algo/detectors/sts/UnpackSts.h
new file mode 100644
index 0000000000000000000000000000000000000000..90ccc1392c23e2bc6b85d66756ffb2fdba30511e
--- /dev/null
+++ b/algo/detectors/sts/UnpackSts.h
@@ -0,0 +1,128 @@
+/* Copyright (C) 2021 GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt
+ SPDX-License-Identifier: GPL-3.0-only
+ Authors: Pierre-Alain Loizeau, Volker Friese [committer] */
+
+#ifndef CBM_ALGO_UNPACKSTS_H
+#define CBM_ALGO_UNPACKSTS_H 1
+
+
+#include "CbmStsDigi.h"
+
+#include "MicrosliceDescriptor.hpp"
+#include "Timeslice.hpp"
+
+#include <cassert>
+#include <cstddef>
+#include <cstdint>
+#include <memory>
+#include <vector>
+
+#include "StsXyterMessage.h"
+
+namespace cbm::algo
+{
+
+
+ /** @struct UnpackStsAsicPar
+ ** @author Volker Friese <v.friese@gsi.de>
+ ** @since 25 November 2021
+ ** @brief Unpacking parameters for one eLink / ASIC
+ **/
+ struct UnpackStsElinkPar {
+ uint32_t fAddress = 0; ///< CbmStsAddress for the connected module
+ uint32_t fAsicNr = 0; ///< Number of connected ASIC within the module
+ uint64_t fTimeOffset = 0.; ///< Time calibration parameter
+ double fAdcOffset = 0.; ///< Charge calibration parameter
+ double fAdcGain = 0.; ///< Charge calibration parameter
+ };
+
+
+ /** @struct UnpackStsPar
+ ** @author Volker Friese <v.friese@gsi.de>
+ ** @since 25 November 2021
+ ** @brief Parameters required for the STS unpacking (specific to one component)
+ **/
+ struct UnpackStsPar {
+
+ uint32_t fNumChansPerAsic = 0; ///< Number of channels per ASIC
+ uint32_t fNumAsicsPerModule = 0; ///< Number of ASICS per module
+ uint64_t fEpochsPerCycle = 0; ///< TS_MSB epochs per epoch cycle
+ uint64_t fEpochLength = 0; ///< Length of TS_MSB epoch in clock cycles
+ uint32_t fClockCycleNom = 0; ///< Clock cycle nominator [ns]
+ uint32_t fClockCycleDen = 0.; ///< Clock cycle denominator
+ std::vector<UnpackStsElinkPar> fElinkParams; ///< Parameters for each eLink
+
+ size_t GetNumElinks() const { return fElinkParams.size(); }
+
+ const UnpackStsElinkPar& GetElinkPar(size_t eLink) const
+ {
+ assert(eLink < GetNumElinks());
+ return fElinkParams[eLink];
+ }
+ };
+
+
+ /** @class UnpackSts
+ ** @author Pierre-Alain Loizeau <p.-a.loizeau@gsi.de>
+ ** @author Volker Friese <v.friese@gsi.de>
+ ** @since 25 November 2021
+ ** @brief Unpack algorithm for STS
+ **/
+ class UnpackSts {
+
+ public:
+ /** @brief Default constructor **/
+ UnpackSts() {};
+
+
+ /** @brief Destructor **/
+ ~UnpackSts() {};
+
+
+ /** @brief Algorithm execution
+ ** @param msContent Microslice payload
+ ** @param msDescr Microslice descriptor
+ ** @param tTimeslice Unix start time of timeslice [ns]
+ ** @return STS digi data
+ **/
+ std::vector<CbmStsDigi> operator()(const uint8_t* msContent, const fles::MicrosliceDescriptor& msDescr,
+ const uint64_t tTimeslice);
+
+ /** @brief Set the parameter container
+ ** @param params Pointer to parameter container
+ **/
+ void SetParams(std::unique_ptr<UnpackStsPar> params)
+ {
+ fParams = std::move(params);
+ fCycleLength = (fParams->fEpochsPerCycle * fParams->fEpochLength * fParams->fClockCycleNom);
+ fCycleLength /= fParams->fClockCycleDen;
+ }
+
+
+ private:
+ /** @brief Process an epoch message (TS_MSB)
+ ** @param message SMX message (32-bit word)
+ ** @param digiVec Vector to append the created digi to
+ **/
+ void ProcessTsmsbMessage(const stsxyter::Message& message);
+
+ /** @brief Process a hit message
+ ** @param message SMX message (32-bit word)
+ ** @param digiVec Vector to append the created digi to
+ **/
+ void ProcessHitMessage(const stsxyter::Message& message, std::vector<CbmStsDigi>& digiVec) const;
+
+ private:
+ uint64_t fCurrentTsTime = 0; ///< Unix time of timeslice in ns
+ uint64_t fCurrentCycle = 0; ///< Current epoch cycle
+ uint32_t fCurrentEpoch = 0; ///< Current epoch number within epoch cycle
+ uint64_t fCurrentEpochTime = 0; ///< Unix time of current epoch in clock cycles
+ uint64_t fCycleLength = 0; ///< Epoch cycle length in ns
+
+ std::unique_ptr<UnpackStsPar> fParams = nullptr; ///< Parameter container
+ };
+
+
+} /* namespace cbm::algo */
+
+#endif /* CBM_ALGO_UNPACKSTS_H */