feat: diode, math (stats), dBm, temp, restore mode

Add diode mode, math (min/max/avg), temp - k type thermocouple and
thermistor (only 5k tho..), restore mode to the one we came from when
exiting feature.
Add all features to USB-CDC interface, clean up state a bit (union)

inc/gpib_defs.h

@@ -62,6 +62,92 @@
 #define GPIB_TAG_BASE 0x40  // Talk Address Group base
 #define GPIB_SCG_BASE 0x60  // Secondary Command Group base
 
+/* HP3478A */
+// Measurement Function (F)
+#define HP3478A_FUNC_DC_VOLTS "F1"
+#define HP3478A_FUNC_AC_VOLTS "F2"
+#define HP3478A_FUNC_OHMS_2WIRE "F3"
+#define HP3478A_FUNC_OHMS_4WIRE "F4"
+#define HP3478A_FUNC_DC_CURRENT "F5"
+#define HP3478A_FUNC_AC_CURRENT "F6"
+#define HP3478A_FUNC_OHMS_EXT "F7"
+
+// Range (R)
+#define HP3478A_RANGE_NEG_2 "R-2" /* 30mV DC */
+#define HP3478A_RANGE_NEG_1 "R-1" /* 300mV (AC/DC) or 300mA (AC/DC) */
+#define HP3478A_RANGE_0 "R0"      /* 3V (AC/DC) or 3A (AC/DC) */
+#define HP3478A_RANGE_1 "R1"      /* 30V (AC/DC) or 30 Ohm */
+#define HP3478A_RANGE_2 "R2"      /* 300V (AC/DC) or 300 Ohm */
+#define HP3478A_RANGE_3 "R3"      /* 3K Ohm */
+#define HP3478A_RANGE_4 "R4"      /* 30K Ohm */
+#define HP3478A_RANGE_5 "R5"      /* 300K Ohm */
+#define HP3478A_RANGE_6 "R6"      /* 3M Ohm */
+#define HP3478A_RANGE_7 "R7"      /* 30M Ohm */
+#define HP3478A_RANGE_AUTO "RA"   /* Autorange */
+
+// Display / Integration Time (N)
+#define HP3478A_DIGITS_3_5 "N3" /* 3 1/2 digit (Fastest) */
+#define HP3478A_DIGITS_4_5 "N4" /* 4 1/2 digit (1 PLC integration) */
+#define HP3478A_DIGITS_5_5 "N5" /* 5 1/2 digit (Best noise rejection) */
+
+// Trigger (T)
+#define HP3478A_TRIG_INTERNAL "T1" /* Internal trigger */
+#define HP3478A_TRIG_EXTERNAL "T2" /* External trigger pulse */
+#define HP3478A_TRIG_SINGLE "T3"   /* Single trigger (Software/GET) */
+#define HP3478A_TRIG_HOLD "T4"     /* Trigger Hold (Idle) */
+#define HP3478A_TRIG_FAST "T5"     /* Fast Trigger (No settling delay) */
+
+// Autozero (Z)
+#define HP3478A_AUTOZERO_OFF "Z0"
+#define HP3478A_AUTOZERO_ON "Z1"
+
+// Write to Display (D)
+#define HP3478A_DISP_NORMAL "D1" /* Return to normal measurement display */
+#define HP3478A_DISP_TEXT "D2"   /* Prefix: Follow with up to 12 chars */
+#define HP3478A_DISP_TEXT_FAST \
+  "D3" /* Like D2, but stops updating (faster read rate) */
+
+// Preset Commands (H)
+#define HP3478A_PRESET_HOME "H0"
+#define HP3478A_MEAS_DC_VOLTS "H1"
+#define HP3478A_MEAS_AC_VOLTS "H2"
+#define HP3478A_MEAS_OHMS_2WIRE "H3"
+#define HP3478A_MEAS_OHMS_4WIRE "H4"
+#define HP3478A_MEAS_DC_CURRENT "H5"
+#define HP3478A_MEAS_AC_CURRENT "H6"
+#define HP3478A_MEAS_OHMS_EXT "H7"
+
+#define HP3478A_CMD_STATUS_BYTE "B"
+
+// Serial Poll Register (K)
+#define HP3478A_CMD_SRQ_CLEAR "K"
+
+// Error Register (E)
+#define HP3478A_CMD_ERR_READ "E"
+
+// Front/Rear Switch (S)
+#define HP3478A_CMD_SWITCH_READ "S"
+
+// SRQ Mask (M)
+#define HP3478A_CMD_SRQ_MASK_PFX "M"
+
+#define HP3478A_MASK_DATA_READY 0x01   /* Bit 0: Reading available to bus */
+#define HP3478A_MASK_UNUSED_B1 0x02    /* Bit 1: Not used */
+#define HP3478A_MASK_SYNTAX_ERR 0x04   /* Bit 2: Syntax error */
+#define HP3478A_MASK_HARDWARE_ERR 0x08 /* Bit 3: Hardware error */
+#define HP3478A_MASK_KEYBOARD_SRQ \
+  0x10                             /* Bit 4: Front panel 'SRQ' key pressed */
+#define HP3478A_MASK_CAL_FAIL 0x20 /* Bit 5: Calibration procedure failed */
+#define HP3478A_MASK_ZERO_B6 0x40  /* Bit 6: Always zero */
+#define HP3478A_MASK_POWER_ON 0x80 /* Bit 7: PON Switched/Device Clear */
+
+// "M20" -> SRQ on Button Only
+#define HP3478A_CMD_MASK_BTN_ONLY "M20"
+// "M21" -> SRQ on Button OR Data Ready
+#define HP3478A_CMD_MASK_BTN_DATA "M21"
+// "M00" -> Clear Mask (Disable SRQ)
+#define HP3478A_CMD_MASK_CLEAR "M00"
+
 #define GPIB_ASSERT(pin) funDigitalWrite(pin, 0)
 #define GPIB_RELEASE(pin) funDigitalWrite(pin, 1)
 #define GPIB_READ(pin) funDigitalRead(pin)

inc/usb_config.h

@@ -22,10 +22,10 @@
 
 #define FUSB_USB_VID 0x1209
 #define FUSB_USB_PID 0x3478
-#define FUSB_USB_REV 0x0100
+#define FUSB_USB_REV 0x0110
 #define FUSB_STR_MANUFACTURER u"Open Source GPIB"
 #define FUSB_STR_PRODUCT      u"HP3478A Internal Adapter"
-#define FUSB_STR_SERIAL       u"3478A-USB-001"
+#define FUSB_STR_SERIAL       u"3478A-USB-110"
 
 //Taken from http://www.usbmadesimple.co.uk/ums_ms_desc_dev.htm
 static const uint8_t device_descriptor[] = {