feat: Adding XIT RIT in the Flex panel

internal/cat/cat.go

@@ -304,6 +304,13 @@ type FlexTXState struct {
 	ANFLevel     int      `json:"anf_level"`
 	WNB          bool     `json:"wnb"`
 	WNBLevel     int      `json:"wnb_level"`
+	// RIT/XIT — offsets applied to the active slice's RX / TX frequency without
+	// moving the slice. The offset survives the switch being turned off, so
+	// re-enabling restores it, exactly like the radio's own knob.
+	RIT     bool `json:"rit"`
+	RITFreq int  `json:"rit_freq"`
+	XIT     bool `json:"xit"`
+	XITFreq int  `json:"xit_freq"`
 	// CW / mode-specific controls.
 	Mode           string `json:"mode,omitempty"` // active slice mode (CW/USB/LSB/DIGU…)
 	CWSpeed        int    `json:"cw_speed"`
@@ -378,6 +385,10 @@ type FlexController interface {
 	SetAPFLevel(int) error
 	SetWNB(bool) error
 	SetWNBLevel(int) error
+	SetRIT(bool) error
+	SetRITFreq(int) error
+	SetXIT(bool) error
+	SetXITFreq(int) error
 	// CW keyer + mode-specific controls.
 	SetCWSpeed(int) error
 	SetCWPitch(int) error

internal/cat/flex.go

@@ -90,8 +90,12 @@ type flexSlice struct {
 	apfLevel     int
 	wnb          bool // wideband noise blanker
 	wnbLevel     int
-	filterLo     int      // slice filter low cut (Hz)
-	filterHi     int      // slice filter high cut (Hz)
+	rit          bool // receive incremental tuning enabled
+	ritFreq      int  // RIT offset in Hz (negative = down)
+	xit          bool // transmit incremental tuning enabled
+	xitFreq      int  // XIT offset in Hz
+	filterLo     int  // slice filter low cut (Hz)
+	filterHi     int  // slice filter high cut (Hz)
 	rxAnt        string   // selected RX antenna (e.g. ANT1, ANT2, RX_A)
 	txAnt        string   // selected TX antenna
 	antList      []string // antennas valid for this slice (RX side)
@@ -804,6 +808,14 @@ func (f *Flex) handleStatus(payload string) {
 			s.wnb = val == "1"
 		case "wnb_level":
 			s.wnbLevel = atoiDefault(val, s.wnbLevel)
+		case "rit_on":
+			s.rit = val == "1"
+		case "rit_freq":
+			s.ritFreq = atoiDefault(val, s.ritFreq)
+		case "xit_on":
+			s.xit = val == "1"
+		case "xit_freq":
+			s.xitFreq = atoiDefault(val, s.xitFreq)
 		case "filter_lo":
 			s.filterLo = atoiDefault(val, s.filterLo)
 		case "filter_hi":
@@ -1315,6 +1327,10 @@ func (f *Flex) FlexState() FlexTXState {
 		st.APFLevel = rx.apfLevel
 		st.WNB = rx.wnb
 		st.WNBLevel = rx.wnbLevel
+		st.RIT = rx.rit
+		st.RITFreq = rx.ritFreq
+		st.XIT = rx.xit
+		st.XITFreq = rx.xitFreq
 		st.FilterLo = rx.filterLo
 		st.FilterHi = rx.filterHi
 		st.RXAnt = rx.rxAnt
@@ -1383,6 +1399,14 @@ func (f *Flex) sendSlice(param string, val any) error {
 			rx.rxAnt = fmt.Sprint(val)
 		case "txant":
 			rx.txAnt = fmt.Sprint(val)
+		case "rit_on":
+			rx.rit = val == "1"
+		case "rit_freq":
+			rx.ritFreq = toInt(val)
+		case "xit_on":
+			rx.xit = val == "1"
+		case "xit_freq":
+			rx.xitFreq = toInt(val)
 		}
 	}
 	f.mu.Unlock()
@@ -1490,6 +1514,26 @@ func (f *Flex) SetNR(on bool) error     { return f.sendSlice("nr", boolFlex(on))
 func (f *Flex) SetNRLevel(l int) error  { return f.sendSlice("nr_level", clampLevel(l)) }
 func (f *Flex) SetANF(on bool) error    { return f.sendSlice("anf", boolFlex(on)) }
 func (f *Flex) SetANFLevel(l int) error { return f.sendSlice("anf_level", clampLevel(l)) }
+// RIT/XIT — an offset applied to the RX (RIT) or TX (XIT) frequency of the active
+// slice, without moving the slice itself. SmartSDR keeps the offset even while the
+// switch is off, so turning RIT back on restores the last offset — same as the
+// radio's own knob.
+func (f *Flex) SetRIT(on bool) error      { return f.sendSlice("rit_on", boolFlex(on)) }
+func (f *Flex) SetRITFreq(hz int) error   { return f.sendSlice("rit_freq", clampOffset(hz)) }
+func (f *Flex) SetXIT(on bool) error      { return f.sendSlice("xit_on", boolFlex(on)) }
+func (f *Flex) SetXITFreq(hz int) error   { return f.sendSlice("xit_freq", clampOffset(hz)) }
+
+// clampOffset keeps a RIT/XIT offset inside what SmartSDR accepts (±99 999 Hz).
+func clampOffset(hz int) int {
+	if hz > 99999 {
+		return 99999
+	}
+	if hz < -99999 {
+		return -99999
+	}
+	return hz
+}
+
 func (f *Flex) SetAPF(on bool) error    { return f.sendSlice("apf", boolFlex(on)) }
 func (f *Flex) SetAPFLevel(l int) error { return f.sendSlice("apf_level", clampLevel(l)) }
 func (f *Flex) SetWNB(on bool) error    { return f.sendSlice("wnb", boolFlex(on)) }