avr
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avrdude
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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
This commit is contained in:
Brian S. Dean 2002-11-23 00:47:29 +00:00
parent 2fa7a7c110
commit 6f8adf7abc
1 changed files with 15 additions and 1 deletions
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16
avrdude/main.c
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@ -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_PGM]);
LED_OFF(fd, pgm->pinno[PIN_LED_VFY]); 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 * 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]); ppi_clr(fd, PPIDATA, pgm->pinno[PPI_AVR_BUFF]);
/* /*