added openocd scripts to fix #1

README.md

@@ -179,7 +179,7 @@ make protection
 ```
 or if you don't have `make` or want to run it directly:
 ```bash
-openocd -f ./openocd_m20.cfg -c "init; halt; flash protect 0 0 7 reset; exit"
+openocd -s ./openocd/ -f ./openocd/openocd_m20.cfg -c "init; halt; flash protect 0 0 7 reset; exit"
 ```
 After it finishes you can flash the build firmware:
 ```bash
@@ -187,7 +187,7 @@ make flash
 ```
 or directly
 ```bash
-openocd -f ./openocd_m20.cfg -c "program build/m20.elf verify reset exit"
+openocd -s ./openocd/ -f ./openocd/openocd_m20.cfg -c "program build/m20.elf verify reset exit"
 ```
 After it finishes your sonde should now work with the new firmware.
 

m20/Makefile

@@ -209,9 +209,9 @@ clean:
 
 # flash
 flash:
-	openocd -f ./openocd_m20.cfg -c "program build/m20.elf verify reset exit"
+	openocd -s ./openocd/ -f ./openocd/openocd_m20.cfg -c "program build/m20.elf verify reset exit"
 # remove protect
 protect:
-	openocd -f ./openocd_m20.cfg -c "init; halt; flash protect 0 0 7 reset; exit"
+	openocd -s ./openocd/ -f ./openocd/openocd_m20.cfg -c "init; halt; flash protect 0 0 7 reset; exit"
 
 # *** EOF ***

m20/openocd/mem_helper.tcl

@@ -0,0 +1,38 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
+
+# Helper for common memory read/modify/write procedures
+
+# mrw: "memory read word", returns value of $reg
+proc mrw {reg} {
+	return [read_memory $reg 32 1]
+}
+
+add_usage_text mrw "address"
+add_help_text mrw "Returns value of word in memory."
+
+# mrh: "memory read halfword", returns value of $reg
+proc mrh {reg} {
+	return [read_memory $reg 16 1]
+}
+
+add_usage_text mrh "address"
+add_help_text mrh "Returns value of halfword in memory."
+
+# mrb: "memory read byte", returns value of $reg
+proc mrb {reg} {
+	return [read_memory $reg 8 1]
+}
+
+add_usage_text mrb "address"
+add_help_text mrb "Returns value of byte in memory."
+
+# mmw: "memory modify word", updates value of $reg
+#       $reg <== ((value & ~$clearbits) | $setbits)
+proc mmw {reg setbits clearbits} {
+	set old [mrw $reg]
+	set new [expr {($old & ~$clearbits) | $setbits}]
+	mww $reg $new
+}
+
+add_usage_text mmw "address setbits clearbits"
+add_help_text mmw "Modify word in memory. new_val = (old_val & ~clearbits) | setbits;"

m20/openocd/openocd_m20.cfg

@@ -21,7 +21,7 @@ hla_vid_pid 0x0483 0x3744 0x0483 0x3748 0x0483 0x374b 0x0483 0x374d 0x0483 0x374
 # set any jtag related features
 #
 
-source [find target/swj-dp.tcl]
+source [find swj-dp.tcl]
 source [find mem_helper.tcl]
 
 if { [info exists CHIPNAME] } {

m20/openocd/swj-dp.tcl

@@ -0,0 +1,37 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
+
+# ARM Debug Interface V5 (ADI_V5) utility
+# ... Mostly for SWJ-DP (not SW-DP or JTAG-DP, since
+# SW-DP and JTAG-DP targets don't need to switch based
+# on which transport is active.
+#
+# declare a JTAG or SWD Debug Access Point (DAP)
+# based on the transport in use with this session.
+# You can't access JTAG ops when SWD is active, etc.
+
+# params are currently what "jtag newtap" uses
+# because OpenOCD internals are still strongly biased
+# to JTAG ....  but for SWD, "irlen" etc are ignored,
+# and the internals work differently
+
+# for now, ignore non-JTAG and non-SWD transports
+# (e.g. initial flash programming via SPI or UART)
+
+# split out "chip" and "tag" so we can someday handle
+# them more uniformly irlen too...)
+
+if [catch {transport select}] {
+  echo "Error: unable to select a session transport. Can't continue."
+  shutdown
+}
+
+proc swj_newdap {chip tag args} {
+ if [using_jtag] {
+     eval jtag newtap $chip $tag $args
+ } elseif [using_swd] {
+     eval swd newdap $chip $tag $args
+ } else {
+     echo "Error: transport '[ transport select ]' not supported by swj_newdap"
+     shutdown
+ }
+}