Use -xmode to switch PICkit4 and SNAP application modes

src/avrdude.1

@@ -1519,7 +1519,7 @@ bits after the target AVR, respectively.
 Each AVR unit within the chain shifts by 4 bits.
 Other JTAG units might require a different bit shift count.
 .It Ar hvupdi
-.Nm Power Debugger and Pickit 4 only
+.Nm Power Debugger and PICkit 4 only
 .sp 0.5
 High-voltage UPDI programming is used to enable a UPDI pin that has previously
 been set to RESET or GPIO mode. Use
@@ -1535,6 +1535,19 @@ alone.
 .It Ar help
 Show help menu and exit.
 .El
+.It Ar PICkit 4
+.It Ar MPLAB SNAP
+.Bl -tag -offset indent -width indent
+.It Ar mode=avr,pic
+The PICkit 4 and MPLAB SNAP programmer can only be utilized by Avrdude when in
+AVR mode. Use
+.Ar -xmode=avr
+for switching to AVR mode, or
+.Ar -xmode=pic
+for switching switch PIC mode.
+.It Ar help
+Show help menu and exit.
+.El
 .It Ar Xplained Mini (ISP and UPDI)
 .Bl -tag -offset indent -width indent
 .It Ar suffer=VALUE, suffer

src/doc/avrdude.texi

@@ -1146,6 +1146,21 @@ The current set-voltage can be read by @samp{-xvtarg} alone.
 Show help menu and exit.
 @end table
 
+@cindex Option @code{-x} PICkit 4
+@cindex Option @code{-x} MPLAB SNAP
+@item PICkit 4
+@item MPLAB SNAP
+
+The PICkit 4 and MPLAB SNAP programmers accept the following extended parameters:
+@table @code
+@item @samp{mode=avr,pic}
+The PICkit 4 and MPLAB SNAP programmer can only be utilized by Avrdude when in
+AVR mode. Use @samp{-xmode=avr} for switching to AVR mode, or @samp{-xmode=pic}
+for switching switch PIC mode.
+@item @samp{help}
+Show help menu and exit.
+@end table
+
 @cindex Option @code{-x} Xplained Mini
 @item Xplained Mini
 

src/jtag3.c

@@ -89,6 +89,9 @@ struct pdata
   bool vtarg_set;
   double vtarg_data;
 
+  /* Flag for PICkit4/SNAP mode switching */
+  int pk4_snap_mode;
+
   /* SIB string cache */
   char sib_string[AVR_SIBLEN];
 
@@ -1597,6 +1600,25 @@ static int jtag3_parseextparms(const PROGRAMMER *pgm, const LISTID extparms) {
       }
     }
 
+    else if (str_starts(extended_param, "mode=") &&
+      (str_starts(pgmid, "pickit4") || str_starts(pgmid, "snap"))) {
+      // Flag a switch to AVR mode
+      if (str_caseeq(extended_param, "mode=avr")) {
+        PDATA(pgm)->pk4_snap_mode = PK4_SNAP_MODE_AVR;
+        continue;
+      }
+      // Flag a switch to PIC mode
+      else if (str_caseeq(extended_param, "mode=pic")) {
+        PDATA(pgm)->pk4_snap_mode = PK4_SNAP_MODE_PIC;
+        continue;
+      }
+      else {
+        pmsg_error("invalid mode setting '%s'. Use -xmode=avr or -xmode=pic\n", extended_param);
+        rv = -1;
+        break;
+      }
+    }
+
     else if (str_eq(extended_param, "help")) {
       msg_error("%s -c %s extended options:\n", progname, pgmid);
       if (str_eq(pgm->type, "JTAGICE3"))
@@ -1613,6 +1635,9 @@ static int jtag3_parseextparms(const PROGRAMMER *pgm, const LISTID extparms) {
         msg_error("  -xvtarg                 Read on-board target supply voltage\n");
         msg_error("  -xvtarg=<arg>           Set on-board target supply voltage\n");
       }
+      if(str_starts(pgmid, "pickit4") || str_starts(pgmid, "snap")) {
+        msg_error("  -xmode=avr|pic          Set programmer to AVR or PIC mode\n");
+      }
       msg_error  ("  -xhelp                  Show this help menu and exit\n");
       exit(0);
     }
@@ -1624,7 +1649,7 @@ static int jtag3_parseextparms(const PROGRAMMER *pgm, const LISTID extparms) {
   return rv;
 }
 
-int jtag3_open_common(PROGRAMMER *pgm, const char *port) {
+int jtag3_open_common(PROGRAMMER *pgm, const char *port, const int mode_switch) {
   union pinfo pinfo;
   LNODEID usbpid;
   int rv = -1;
@@ -1639,20 +1664,15 @@ int jtag3_open_common(PROGRAMMER *pgm, const char *port) {
     return -1;
   }
 
-  if (pgm->usbvid)
-    pinfo.usbinfo.vid = pgm->usbvid;
-  else
-    pinfo.usbinfo.vid = USB_VENDOR_ATMEL;
-
-  /* If the config entry did not specify a USB PID, insert the default one. */
+  // If the config entry did not specify a USB PID, insert the default one.
   if (lfirst(pgm->usbpid) == NULL)
     ladd(pgm->usbpid, (void *)USB_DEVICE_JTAGICE3);
 
+  pinfo.usbinfo.vid = pgm->usbvid? pgm->usbvid: USB_VENDOR_ATMEL;
+
 #if defined(HAVE_LIBHIDAPI)
-  /*
-   * Try HIDAPI first.  LibUSB is more generic, but might then cause
-   * troubles for HID-class devices in some OSes (like Windows).
-   */
+  // Try HIDAPI first. LibUSB is more generic, but might
+  // cause trouble for HID-class devices in some OSes
   serdev = &usbhid_serdev;
   for (usbpid = lfirst(pgm->usbpid); rv < 0 && usbpid != NULL; usbpid = lnext(usbpid)) {
     pinfo.usbinfo.flags = PINFO_FL_SILENT;
@@ -1685,44 +1705,51 @@ int jtag3_open_common(PROGRAMMER *pgm, const char *port) {
   }
 #endif
   if (rv < 0) {
-    // Check if SNAP or PICkit4 is in PIC mode
+    // Check if SNAP or PICkit4 are in PIC mode
     for(LNODEID ln=lfirst(pgm->id); ln; ln=lnext(ln)) {
-      if (str_starts(ldata(ln), "snap")) {
+      if (str_starts(ldata(ln), "snap") || str_starts(ldata(ln), "pickit4")) {
+        bool is_snap_pgm = str_starts(ldata(ln), "snap");
         pinfo.usbinfo.vid = USB_VENDOR_MICROCHIP;
-        pinfo.usbinfo.pid = USB_DEVICE_SNAP_PIC_MODE;
-        int pic_mode = serial_open(port, pinfo, &pgm->fd);
-        if(pic_mode < 0) {
-          // Retry with alternative USB PID
-          pinfo.usbinfo.pid = USB_DEVICE_SNAP_PIC_MODE_ALT;
-          pic_mode = serial_open(port, pinfo, &pgm->fd);
-        }
-        if(pic_mode >= 0) {
-          msg_error("\n");
-          pmsg_error("MPLAB SNAP in PIC mode detected!\n");
-          imsg_error("Use MPLAB X or Microchip Studio to switch to AVR mode\n\n");
-          return -1;
-        }
-      } else if(str_starts(ldata(ln), "pickit4")) {
-        pinfo.usbinfo.vid = USB_VENDOR_MICROCHIP;
-        pinfo.usbinfo.pid = USB_DEVICE_PICKIT4_PIC_MODE;
+        pinfo.usbinfo.pid = is_snap_pgm? USB_DEVICE_SNAP_PIC_MODE: USB_DEVICE_PICKIT4_PIC_MODE;
+        const int bl_pid = is_snap_pgm? USB_DEVICE_SNAP_PIC_MODE_BL: USB_DEVICE_PICKIT4_PIC_MODE_BL;
+        const char *pgmstr = is_snap_pgm? "MPLAB SNAP": "PICkit 4";
+        const unsigned char exit_bl_cmd[] = {0xe6};
+        const unsigned char enter_avr_mode_cmd[] = {0xf0, 0x01};
+        const unsigned char reset_cmd[] = {0xed};
+
         int pic_mode = serial_open(port, pinfo, &pgm->fd);
         if(pic_mode < 0) {
-          // Retry with alternative USB PID
-          pinfo.usbinfo.pid = USB_DEVICE_PICKIT4_PIC_MODE_ALT;
+          // Retry with bootloader USB PID
+          pinfo.usbinfo.pid = bl_pid;
           pic_mode = serial_open(port, pinfo, &pgm->fd);
         }
         if(pic_mode >= 0) {
           msg_error("\n");
-          pmsg_error("PICkit4 in PIC mode detected!\n");
-          imsg_error("Use MPLAB X or Microchip Studio to switch to AVR mode\n\n");
-          return -1;
+          pmsg_error("%s in %s mode detected\n",
+            pgmstr, pinfo.usbinfo.pid == bl_pid? "bootloader": "PIC");
+          if(mode_switch == PK4_SNAP_MODE_AVR) {
+            imsg_error("switching to AVR mode\n");
+            if(pinfo.usbinfo.pid == bl_pid)
+              serial_send(&pgm->fd, exit_bl_cmd, sizeof(exit_bl_cmd));
+            else {
+              serial_send(&pgm->fd, enter_avr_mode_cmd, sizeof(enter_avr_mode_cmd));
+              usleep(250*1000);
+              serial_send(&pgm->fd, reset_cmd, sizeof(reset_cmd));
+            }
+            imsg_error("please run Avrdude again to continue the session\n\n");
+          } else {
+            imsg_error("to switch into AVR mode try\n");
+            imsg_error("avrdude -c%s -p%s -P%s -xmode=avr\n", pgmid, partdesc, port);
+          }
+          serial_close(&pgm->fd);
+          exit(0);
         }
       }
     }
     pmsg_error("no device found matching VID 0x%04x and PID list: ",
                (unsigned) pinfo.usbinfo.vid);
     int notfirst = 0;
-    for (usbpid = lfirst(pgm->usbpid); usbpid != NULL; usbpid = lnext(usbpid)) {
+    for (usbpid = lfirst(pgm->usbpid); usbpid; usbpid = lnext(usbpid)) {
       if (notfirst)
         msg_error(", ");
       msg_error("0x%04x", (unsigned int)(*(int *)(ldata(usbpid))));
@@ -1732,15 +1759,17 @@ int jtag3_open_common(PROGRAMMER *pgm, const char *port) {
     char *serno;
     if ((serno = strchr(port, ':')))
       msg_error(" with SN %s", ++serno);
-
     msg_error("\n");
 
     return -1;
   }
 
+  if (mode_switch == PK4_SNAP_MODE_AVR)
+    pmsg_warning("programmer is already in AVR mode. Ignoring -xmode");
+
+  // The event EP has been deleted by usb_open(), so we are
+  // running on a CMSIS-DAP device, using EDBG protocol
   if (pgm->fd.usb.eep == 0) {
-    /* The event EP has been deleted by usb_open(), so we are
-       running on a CMSIS-DAP device, using EDBG protocol */
     pgm->flag |= PGM_FL_IS_EDBG;
     pmsg_notice2("found CMSIS-DAP compliant device, using EDBG protocol\n");
   }
@@ -1749,11 +1778,22 @@ int jtag3_open_common(PROGRAMMER *pgm, const char *port) {
   if (serdev && serdev->usbsn)
     pgm->usbsn = serdev->usbsn;
 
-  /*
-   * drain any extraneous input
-   */
+  // Drain any extraneous input
   jtag3_drain(pgm, 0);
 
+  // Switch from AVR to PIC mode
+  if (mode_switch == PK4_SNAP_MODE_PIC) {
+    imsg_error("switching to PIC mode\n");
+    unsigned char *resp, buf[] = {SCOPE_GENERAL, CMD3_FW_UPGRADE, 0x00, 0x00, 0x70, 0x6d, 0x6a};
+    if (jtag3_command(pgm, buf, sizeof(buf), &resp, "enter PIC mode") < 0) {
+      imsg_error("entering PIC mode failed\n");
+      return -1;
+    }
+    imsg_error("PIC mode switch successful\n");
+    serial_close(&pgm->fd);
+    exit(0);
+  }
+
   return 0;
 }
 
@@ -1762,8 +1802,9 @@ int jtag3_open_common(PROGRAMMER *pgm, const char *port) {
 static int jtag3_open(PROGRAMMER *pgm, const char *port) {
   pmsg_notice2("jtag3_open()\n");
 
-  if (jtag3_open_common(pgm, port) < 0)
-    return -1;
+  int rc = jtag3_open_common(pgm, port, PDATA(pgm)->pk4_snap_mode);
+  if (rc < 0)
+    return rc;
 
   if (jtag3_getsync(pgm, PARM3_CONN_JTAG) < 0)
     return -1;
@@ -1774,7 +1815,7 @@ static int jtag3_open(PROGRAMMER *pgm, const char *port) {
 static int jtag3_open_dw(PROGRAMMER *pgm, const char *port) {
   pmsg_notice2("jtag3_open_dw()\n");
 
-  if (jtag3_open_common(pgm, port) < 0)
+  if (jtag3_open_common(pgm, port, PDATA(pgm)->pk4_snap_mode) < 0)
     return -1;
 
   if (jtag3_getsync(pgm, PARM3_CONN_DW) < 0)
@@ -1786,7 +1827,7 @@ static int jtag3_open_dw(PROGRAMMER *pgm, const char *port) {
 static int jtag3_open_pdi(PROGRAMMER *pgm, const char *port) {
   pmsg_notice2("jtag3_open_pdi()\n");
 
-  if (jtag3_open_common(pgm, port) < 0)
+  if (jtag3_open_common(pgm, port, PDATA(pgm)->pk4_snap_mode) < 0)
     return -1;
 
   if (jtag3_getsync(pgm, PARM3_CONN_PDI) < 0)
@@ -1804,7 +1845,7 @@ static int jtag3_open_updi(PROGRAMMER *pgm, const char *port) {
     msg_notice2(" %d", *(int *) ldata(ln));
   msg_notice2("\n");
 
-  if (jtag3_open_common(pgm, port) < 0)
+  if (jtag3_open_common(pgm, port, PDATA(pgm)->pk4_snap_mode) < 0)
     return -1;
 
   if (jtag3_getsync(pgm, PARM3_CONN_UPDI) < 0)
@@ -3107,7 +3148,7 @@ static int jtag3_chip_erase_tpi(const PROGRAMMER *pgm, const AVRPART *p) {
 static int jtag3_open_tpi(PROGRAMMER *pgm, const char *port) {
   pmsg_notice2("jtag3_open_tpi()\n");
 
-  if (jtag3_open_common(pgm, port) < 0)
+  if (jtag3_open_common(pgm, port, PDATA(pgm)->pk4_snap_mode) < 0)
     return -1;
   return 0;
 }

src/jtag3.h

@@ -25,7 +25,7 @@
 extern "C" {
 #endif
 
-int  jtag3_open_common(PROGRAMMER *pgm, const char *port);
+int  jtag3_open_common(PROGRAMMER *pgm, const char *port, const int mode_switch);
 int  jtag3_send(const PROGRAMMER *pgm, unsigned char *data, size_t len);
 int  jtag3_recv(const PROGRAMMER *pgm, unsigned char **msg);
 void jtag3_close(PROGRAMMER * pgm);

src/jtag3_private.h

@@ -115,6 +115,7 @@
 #define CMD3_GET_ID                0x12
 #define CMD3_START_DW_DEBUG        0x13
 #define CMD3_MONCON_DISABLE        0x17
+#define CMD3_FW_UPGRADE            0x50
 
 /* AVR ISP scope: no commands of its own */
 
@@ -381,6 +382,11 @@
 
 #define DATA_OFFSET                    0x1000000
 
+// Constants for setting a PICkit4 or SNAP in AVR or PIC mode
+#define PK4_SNAP_MODE_DEFAULT 0 // Do not switch mode
+#define PK4_SNAP_MODE_AVR     1 // Switch to AVR mode
+#define PK4_SNAP_MODE_PIC     2 // Switch to PIC mode
+
 #if !defined(JTAG3_PRIVATE_EXPORTED)
 
 struct mega_device_desc {

src/stk500v2.c

@@ -2068,6 +2068,25 @@ static int stk500v2_jtag3_parseextparms(const PROGRAMMER *pgm, const LISTID extp
       }
     }
 
+    else if (str_starts(extended_param, "mode=") &&
+      (str_starts(pgmid, "pickit4") || str_starts(pgmid, "snap"))) {
+      // Flag a switch to AVR mode
+      if (str_caseeq(extended_param, "mode=avr")) {
+        PDATA(pgm)->pk4_snap_mode = PK4_SNAP_MODE_AVR;
+        continue;
+      }
+      // Flag a switch to PIC mode
+      else if (str_caseeq(extended_param, "mode=pic")) {
+        PDATA(pgm)->pk4_snap_mode = PK4_SNAP_MODE_PIC;
+        continue;
+      }
+      else {
+        pmsg_error("invalid mode setting '%s'. Use -xmode=avr or -xmode=pic\n", extended_param);
+        rv = -1;
+        break;
+      }
+    }
+
     else if (str_eq(extended_param, "help")) {
       msg_error("%s -c %s extended options:\n", progname, pgmid);
       if(str_starts(pgmid, "xplainedmini")) {
@@ -2080,6 +2099,8 @@ static int stk500v2_jtag3_parseextparms(const PROGRAMMER *pgm, const LISTID extp
         msg_error("  -xvtarg               Read on-board target supply voltage\n");
         msg_error("  -xvtarg=<arg>         Set on-board target supply voltage\n");
       }
+      if(str_starts(pgmid, "pickit4") || str_starts(pgmid, "snap"))
+        msg_error("  -xmode=avr|pic        Set programmer to AVR or PIC mode\n");
       msg_error  ("  -xhelp                Show this help menu and exit\n");
       exit(0);
     }
@@ -4243,10 +4264,11 @@ static int stk500v2_jtag3_open(PROGRAMMER *pgm, const char *port) {
   void *mycookie;
   int rv;
 
-  pmsg_notice2("stk500v2_jtag3_open()\n");
+  pmsg_notice2("%s()\n", __func__);
 
-  if (jtag3_open_common(pgm, port) < 0)
-    return -1;
+  rv = jtag3_open_common(pgm, port, PDATA(pgm)->pk4_snap_mode);
+  if (rv < 0)
+    return rv;
 
   mycookie = pgm->cookie;
   pgm->cookie = PDATA(pgm)->chained_pdata;

src/stk500v2_private.h

@@ -298,9 +298,12 @@ struct pdata
   bool fosc_set;
   double fosc_data;
 
-  // Set STK500 XTAL frequency
+  /* Set STK500 XTAL frequency */
   unsigned xtal;
 
+  /* Flag for PICkit4/SNAP mode switching */
+  int pk4_snap_mode;
+
   const AVRPART *lastpart;
 
   /* Start address of Xmega boot area */