The last write/erase can fail with -c jtag2updi

[stefanrueger]

Based on a comment my @askn37 and test by @mcuee. Depending where one stands on this this is limitation/bug in the FW and/or a bug in avrdude (not recognising this limitation).

[mcuee]

The comment by @askn37
#1649 (comment)

In my opinion, the original JTAG2UPDI has the following limitations:

1. The last operation performed before ending the session must not be a write or erase. That operation may be lost. Many users may not be aware of this, as this is typically a write-verify pair. Adding a delay after the session ends does not solve the problem. This also applies to Nano Every.
2. Any process that manipulates the status LED after a series of sessions has completed conflicts with starting a new session. The built-in timer malfunctions and times out, making it impossible to continue. To avoid this, a 1-2 second delay is required after the previous session ends. This is not the case with Nano Every, but it has a similar timer clearing process, so adding a short delay is recommended.

[mcuee]

The initial work-around by @askn37 was to change the test script.
#1649 (comment)

diff --git a/tools/test-avrdude b/tools/test-avrdude
index 85059976..1ad5d23b 100755
--- a/tools/test-avrdude
+++ b/tools/test-avrdude
@@ -326,7 +326,7 @@ for (( p=0; p<$arraylength; p++ )); do
 
       if [ -n "$EE_SIZE" ]; then
         specify="fuse access: set eesave fusebit to delete EEPROM on chip erase"
-        command=(${avrdude[@]} -T '"config eesave=ee*erased"')
+        command=(${avrdude[@]} -T '"config eesave=ee*erased; config eesave"')
         execute "${command[@]}" > $outfile
         sed -e/^config/d -e/"> "/d $outfile > ${outfile}-2
         result [[ ! -s ${outfile}-2  '&&' ! -s $logfile ]]

[mcuee]

Later @askn37 provided a patch which fixes the issue.
#1649 (comment)

diff --git a/src/jtagmkII.c b/src/jtagmkII.c
index 0aecb7ce..7ad73c84 100644
--- a/src/jtagmkII.c
+++ b/src/jtagmkII.c
@@ -87,6 +87,9 @@ struct pdata
   /* Major firmware version (needed for Xmega programming) */
   unsigned int fwver;
 
+  /* Remember if the last execution was a memory write */
+  int taint_write;
+
 #define FLAGS32_INIT_SMC      1 // Part will undergo chip erase
 #define FLAGS32_WRITE         2 // At least one write operation specified
   // Couple of flag bits for AVR32 programming
@@ -142,6 +145,7 @@ static int jtagmkII_paged_write(const PROGRAMMER *pgm, const AVRPART *p, const A
                                 unsigned int addr, unsigned int n_bytes);
 static unsigned char jtagmkII_mtype(const PROGRAMMER *pgm, const AVRPART *p, unsigned long addr);
 static unsigned int jtagmkII_memaddr(const PROGRAMMER *pgm, const AVRPART *p, const AVRMEM *m, unsigned long addr);
+static int jtagmkII_updi_term_keep_alive(const PROGRAMMER *pgm, const AVRPART *p_unused);
 
 // AVR32
 #define ERROR_SAB 0xFFFFFFFF
@@ -850,6 +854,7 @@ static int jtagmkII_chip_erase(const PROGRAMMER *pgm, const AVRPART *p) {
   if (!(p->prog_modes & (PM_PDI | PM_UPDI)))
       pgm->initialize(pgm, p);
 
+  PDATA(pgm)->taint_write = 1;
   return 0;
 }
 
@@ -1105,6 +1110,13 @@ static int jtagmkII_program_disable(const PROGRAMMER *pgm) {
   if (!PDATA(pgm)->prog_enabled)
     return 0;
 
+  // Delay early termination to ensure memory rewrite operations.
+  if (PDATA(pgm)->taint_write) {
+    pmsg_notice2("jtagmkII_program_disable(): Delay after writing: ");
+    jtagmkII_updi_term_keep_alive(pgm, /* unused */ (AVRPART*)NULL);
+    jtagmkII_updi_term_keep_alive(pgm, /* unused */ (AVRPART*)NULL);
+  }
+
   buf[0] = CMND_LEAVE_PROGMODE;
   pmsg_notice2("jtagmkII_program_disable(): "
     "Sending leave progmode command: ");
@@ -1128,6 +1140,7 @@ static int jtagmkII_program_disable(const PROGRAMMER *pgm) {
     return -1;
   }
 
+  PDATA(pgm)->taint_write  = 0;
   PDATA(pgm)->prog_enabled = 0;
   (void)jtagmkII_reset(pgm, 0x01);
 
@@ -2012,6 +2025,7 @@ static int jtagmkII_paged_write(const PROGRAMMER *pgm, const AVRPART *p, const A
   free(cmd);
   serial_recv_timeout = otimeout;
 
+  PDATA(pgm)->taint_write = 1;
   return n_bytes;
 }
 
@@ -2102,6 +2116,7 @@ static int jtagmkII_paged_load(const PROGRAMMER *pgm, const AVRPART *p, const AV
   }
   serial_recv_timeout = otimeout;
 
+  PDATA(pgm)->taint_write = 0;
   return n_bytes;
 }
 
@@ -2290,6 +2305,7 @@ retry:
     *value = resp[1];
 
   free(resp);
+  PDATA(pgm)->taint_write = 0;
   return 0;
 
 fail:
@@ -2400,6 +2416,7 @@ retry:
   }
 
   free(resp);
+  PDATA(pgm)->taint_write = 1;
   return 0;
 
 fail:

[mcuee]

@stefanrueger has adapted the patch to PR #1662 and I have tested to be good.

• Read the signature on -c jtag2updi exit if last op was write/erase #1662