Mercurial > avr_jtag
diff src/jtag.c @ 5:eb14cac68cbb
Transite TAP controller to shift state.
- shift commands will transite state machine of TAP controller to
shift state before starting shifting.
| author | Thinker K.F. Li <thinker@branda.to> |
|---|---|
| date | Sun, 22 Feb 2009 13:55:50 +0800 |
| parents | 6b1594fb668f |
| children | 61f27549de57 |
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--- a/src/jtag.c Sun Feb 22 12:54:45 2009 +0800 +++ b/src/jtag.c Sun Feb 22 13:55:50 2009 +0800 @@ -30,6 +30,11 @@ } while(0) #define GET_TDO() (JTAG_PIN & _BV(JTAG_TDO)) +/*! + * Before shifting registers, TAP controller must move to last state before + * shift state. The state machine transite to shift state when shifting + * starts. + */ void jtag_tms(char *buf, int nbits) { int i; int nbytes, byte; @@ -88,6 +93,11 @@ int byteoff, bitoff; int bit; + /* Transite to shift state. + * \sa jtag_tms() + */ + pin_lo(JTAG_PORT, JTAG_TMS); + nbytes = nbits / 8; for(i = 0; i < nbytes; i++) { byte = buf[i]; @@ -143,6 +153,11 @@ int byteoff, bitoff; int bit; + /* Transite to shift state. + * \sa jtag_tms() + */ + pin_lo(JTAG_PORT, JTAG_TMS); + nbytes = nbits / 8; for(i = 0; i < nbytes; i++) { byte = ibuf[i];