From 3d5beb40dfab471ca70f7c766ada1d81739e4f3e Mon Sep 17 00:00:00 2001
From: Joerg Wunsch <j@uriah.heep.sax.de>
Date: Tue, 7 Oct 2014 15:21:14 +0000
Subject: [PATCH] bug #42267: jtag3isp fails to read lock and fuse bytes
directly after changing lock byte * stk500v2.c (stk500isp_write_byte): As a
workaround for broken tool firmware, add 10 ms of delay before returning from
any single-byte write operation.
git-svn-id: svn://svn.savannah.nongnu.org/avrdude/trunk/avrdude@1337 81a1dc3b-b13d-400b-aceb-764788c761c2
---
ChangeLog | 8 ++++++++
NEWS | 2 ++
stk500v2.c | 23 ++++++++++-------------
3 files changed, 20 insertions(+), 13 deletions(-)
diff --git a/ChangeLog b/ChangeLog
index 428cbdfd..a16699e0 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2014-10-07 Joerg Wunsch <j.gnu@uriah.heep.sax.de>
+
+ bug #42267: jtag3isp fails to read lock and fuse bytes directly
+ after changing lock byte
+ * stk500v2.c (stk500isp_write_byte): As a workaround for broken
+ tool firmware, add 10 ms of delay before returning from any
+ single-byte write operation.
+
2014-10-06 Joerg Wunsch <j.gnu@uriah.heep.sax.de>
* stk500v2.c: Use stk500isp_read_byte/stk500isp_write_byte for
diff --git a/NEWS b/NEWS
index 99c1068d..e952b983 100644
--- a/NEWS
+++ b/NEWS
@@ -22,6 +22,8 @@ Current:
* Bugfixes
- bug #22248: Read efuse error (partial fix)
+ - bug #42267: jtag3isp fails to read lock and fuse bytes directly
+ after changing lock byte
* Internals:
- ...
diff --git a/stk500v2.c b/stk500v2.c
index fd8b5e1b..53b92917 100644
--- a/stk500v2.c
+++ b/stk500v2.c
@@ -2241,19 +2241,16 @@ static int stk500isp_write_byte(PROGRAMMER * pgm, AVRPART * p, AVRMEM * mem,
return -1;
}
- if (buf[0] == CMD_PROGRAM_FUSE_ISP) {
- /*
- * The JTAGICE3 needs one leave progmode / enter progmode cycle
- * after writing fuses, before being able to read them back.
- */
- buf[0] = CMD_LEAVE_PROGMODE_ISP;
- buf[1] = 1; // preDelay;
- buf[2] = 1; // postDelay;
-
- stk500v2_command(pgm, buf, 3, sizeof(buf));
-
- pgm->program_enable(pgm, p);
- }
+ /*
+ * Prevent verification readback to be too fast, see
+ * https://savannah.nongnu.org/bugs/index.php?42267
+ *
+ * After all, this is just an ugly hack working around some
+ * brokeness in the Atmel firmware starting with the AVRISPmkII (the
+ * old JTAGICEmkII isn't affected). Let's hope 10 ms of additional
+ * delay are good enough for everyone.
+ */
+ usleep(10000);
return 0;
}