From 6f8adf7abcf8c5a1f3235452783ff10904190b0e Mon Sep 17 00:00:00 2001
From: "Brian S. Dean" <bsd@bsdhome.com>
Date: Sat, 23 Nov 2002 00:47:29 +0000
Subject: [PATCH] When getting ready to initiate communications with the AVR
device, first pull /RESET low for a short period of time before enabling the
buffer chip. This sequence allows the AVR to be reset before the buffer is
enabled to avoid a short period of time where the AVR may be driving the
programming lines at the same time the programmer tries to. Of course, if a
buffer is being used, then the /RESET line from the programmer needs to be
directly connected to the AVR /RESET line and not via the buffer chip.
git-svn-id: svn://svn.savannah.nongnu.org/avrdude/trunk@156 81a1dc3b-b13d-400b-aceb-764788c761c2
---
avrdude/main.c | 16 +++++++++++++++-
1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/avrdude/main.c b/avrdude/main.c
index a476bb8b..6eeddfe9 100644
--- a/avrdude/main.c
+++ b/avrdude/main.c
@@ -839,10 +839,24 @@ int main(int argc, char * argv [])
LED_OFF(fd, pgm->pinno[PIN_LED_PGM]);
LED_OFF(fd, pgm->pinno[PIN_LED_VFY]);
+
+ /*
+ * Prepare to start talking to the connected device - pull reset low
+ * first, delay a few milliseconds, then enable the buffer. This
+ * sequence allows the AVR to be reset before the buffer is enabled
+ * to avoid a short period of time where the AVR may be driving the
+ * programming lines at the same time the programmer tries to. Of
+ * course, if a buffer is being used, then the /RESET line from the
+ * programmer needs to be directly connected to the AVR /RESET line
+ * and not via the buffer chip.
+ */
+
+ ppi_setpin(fd, pgm->pinno[PIN_AVR_RESET], 0);
+ usleep(1);
+
/*
* enable the 74367 buffer, if connected; this signal is active low
*/
- /*ppi_setpin(fd, pgm->pinno[PIN_AVR_BUFF], 0);*/
ppi_clr(fd, PPIDATA, pgm->pinno[PPI_AVR_BUFF]);
/*