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 +1535,21 @@ 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
+Switch programmer to AVR or PIC mode, then exit: the PICkit 4 and MPLAB SNAP
+programmer can only be utilised by
+.Nm
+when in AVR mode. Use
+.Ar -xmode=avr
+for switching to AVR mode, or
+.Ar -xmode=pic
+for switching to 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 +1146,22 @@ 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}
+Switch programmer to AVR or PIC mode, then exit: the PICkit 4 and MPLAB SNAP
+programmer can only be utilised by Avrdude when in AVR mode.
+Use @samp{-xmode=avr} for switching to AVR mode, or @samp{-xmode=pic}
+for switching to PIC mode.
+@item @samp{help}
+Show help menu and exit.
+@end table
+
 @cindex Option @code{-x} Xplained Mini
 @item Xplained Mini