Add high-voltage UPDI info to docs

src/avrdude.1

@@ -179,7 +179,7 @@ has a revision 1 hardware and firmware version of at least 5.37 (decimal).
 For ATxmega devices, the JTAGICE3 is supported in PDI mode.
 .Pp
 Atmel-ICE (ARM/AVR) is supported in all modes (JTAG, PDI for Xmega, debugWIRE,
-ISP).
+ISP, UPDI).
 .Pp
 Atmel's XplainedPro boards, using the EDBG protocol (CMSIS-DAP compatible),
 are supported using the "jtag3" programmer type.
@@ -225,7 +225,7 @@ thus the name
 SerialUPDI programmer implementation is based on Microchip's
 .Em pymcuprog Li https://github.com/microchip-pic-avr-tools/pymcuprog
 utility, but it also contains some performance improvements included in
-Spence Kohde's
+Spence Konde's
 .Em DxCore
 Arduino core
 .Li https://github.com/SpenceKonde/DxCore .
@@ -959,9 +959,13 @@ versions of the bootloader.
 .It Ar JTAG ICE mkII
 .It Ar JTAGICE3
 .It Ar Atmel-ICE
+.It Ar Power Debugger
+.It Ar PICkit 4
+.It Ar MPLAB SNAP
 .It Ar AVR Dragon
-When using the JTAG ICE mkII, JTAGICE3, Atmel-ICE or AVR Dragon in JTAG mode, the
+When using the JTAG ICE mkII, JTAGICE3, Atmel-ICE, PICkit 4, MPLAB SNAP,
-following extended parameter is accepted:
+Power Debugger or AVR Dragon in JTAG mode, the following extended parameter
+is accepted:
 .Bl -tag -offset indent -width indent
 .It Ar jtagchain=UB,UA,BB,BA
 Setup the JTAG scan chain for
@@ -976,6 +980,14 @@ 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.
 .El
+.Pp
+The PICkit 4 and the Power Debugger also supports high-voltage UPDI programming.
+This is used to enable a UPDI pin that has previously been set to RESET or
+GPIO mode. High-voltage UPDI can be utilized by using an extended parameter:
+.Bl -tag -offset indent -width indent
+.It Ar hvupdi
+Enable high-voltage UPDI initialization for targets that supports this.
+.El
 .It Ar AVR910
 .Bl -tag -offset indent -width indent
 .It Ar devcode=VALUE

src/doc/avrdude.texi

@@ -250,7 +250,8 @@ See below for the limitations of debugWire.
 For ATxmega devices, the JTAG ICE mkII/3 is supported in PDI mode, provided it
 has a revision 1 hardware and firmware version of at least 5.37 (decimal).
 
-The Atmel-ICE (ARM/AVR) is supported (JTAG, PDI for Xmega, debugWIRE, ISP modes).
+The Atmel-ICE (ARM/AVR) is supported (JTAG, PDI for Xmega, debugWIRE, ISP,
+UPDI).
 
 Atmel's XplainedPro boards, using EDBG protocol (CMSIS-DAP compliant), are
 supported by the ``jtag3'' programmer type.
@@ -843,10 +844,15 @@ accepting extended parameters.
 @table @code
 
 @item JTAG ICE mkII/3
+@itemx Atmel-ICE
+@itemx PICkit 4
+@itemx MPLAB SNAP
+@itemx Power Debugger
 @itemx AVR Dragon
 
-When using the JTAG ICE mkII/3 or AVR Dragon in JTAG mode, the
+When using the JTAG ICE mkII, JTAGICE3, Atmel-ICE, PICkit 4, MPLAB SNAP,
-following extended parameter is accepted:
+Power Debugger or AVR Dragon in JTAG mode, the following extended parameter
+is accepted:
 @table @code
 @item @samp{jtagchain=UB,UA,BB,BA}
 Setup the JTAG scan chain for @var{UB} units before, @var{UA} units
@@ -856,6 +862,14 @@ Each AVR unit within the chain shifts by 4 bits.
 Other JTAG units might require a different bit shift count.
 @end table
 
+The PICkit 4 and the Power Debugger also supports high-voltage UPDI programming.
+This is used to enable a UPDI pin that has previously been set to RESET or
+GPIO mode. High-voltage UPDI can be utilized by using an extended parameter:
+@table @code
+@item @samp{hvupdi}
+Enable high-voltage UPDI initialization for targets that supports this.
+@end table
+
 @cindex @code{-x} AVR910
 @item AVR910