diff options
| author | Keith Packard <keithp@keithp.com> | 2009-03-06 22:52:35 -0800 |
|---|---|---|
| committer | Keith Packard <keithp@keithp.com> | 2009-03-06 22:56:47 -0800 |
| commit | cc0495b7028f4b1189a00707d828a68534d1dea2 (patch) | |
| tree | a7727c8af99af7781f801a00235a6b9fb8d107f1 | |
| parent | 41289e6d8f1767547a33fea349866e928e44910f (diff) | |
Wait for a while when switching the RESET_N line
The cc1111 manual suggests placing a 2.7kΩ resister and 1nF capacitor on the
RESET_N line to filter out noise. This increases the time necessary to reset
the chip to several microseconds which is longer than the interval between
two USB packets. Flush the USB packet queue and sleep for a while after
changing the value on the RESET_N line to make sure the chip sees the state
change.
Signed-off-by: Keith Packard <keithp@keithp.com>
| -rw-r--r-- | lib/ccdbg-command.c | 6 | ||||
| -rw-r--r-- | lib/ccdbg-io.c | 12 | ||||
| -rw-r--r-- | lib/ccdbg.h | 9 |
3 files changed, 25 insertions, 2 deletions
diff --git a/lib/ccdbg-command.c b/lib/ccdbg-command.c index d99e8ff3..74313bdf 100644 --- a/lib/ccdbg-command.c +++ b/lib/ccdbg-command.c @@ -27,11 +27,12 @@ ccdbg_debug_mode(struct ccdbg *dbg) ccdbg_debug(CC_DEBUG_COMMAND, "#\n"); ccdbg_send(dbg, CC_CLOCK|CC_DATA|CC_RESET_N, CC_CLOCK|CC_DATA|CC_RESET_N); ccdbg_send(dbg, CC_CLOCK|CC_DATA|CC_RESET_N, CC_DATA ); + ccdbg_wait_reset(dbg); ccdbg_send(dbg, CC_CLOCK|CC_DATA|CC_RESET_N, CC_CLOCK|CC_DATA ); ccdbg_send(dbg, CC_CLOCK|CC_DATA|CC_RESET_N, CC_DATA ); ccdbg_send(dbg, CC_CLOCK|CC_DATA|CC_RESET_N, CC_CLOCK|CC_DATA ); ccdbg_send(dbg, CC_CLOCK|CC_DATA|CC_RESET_N, CC_DATA|CC_RESET_N); - ccdbg_sync_io(dbg); + ccdbg_wait_reset(dbg); } void @@ -42,11 +43,12 @@ ccdbg_reset(struct ccdbg *dbg) ccdbg_debug(CC_DEBUG_COMMAND, "#\n"); ccdbg_send(dbg, CC_CLOCK|CC_DATA|CC_RESET_N, CC_CLOCK|CC_DATA|CC_RESET_N); ccdbg_send(dbg, CC_CLOCK|CC_DATA|CC_RESET_N, CC_CLOCK|CC_DATA ); + ccdbg_wait_reset(dbg); ccdbg_send(dbg, CC_CLOCK|CC_DATA|CC_RESET_N, CC_CLOCK|CC_DATA ); ccdbg_send(dbg, CC_CLOCK|CC_DATA|CC_RESET_N, CC_CLOCK|CC_DATA ); ccdbg_send(dbg, CC_CLOCK|CC_DATA|CC_RESET_N, CC_CLOCK|CC_DATA ); ccdbg_send(dbg, CC_CLOCK|CC_DATA|CC_RESET_N, CC_CLOCK|CC_DATA|CC_RESET_N); - ccdbg_sync_io(dbg); + ccdbg_wait_reset(dbg); } uint8_t diff --git a/lib/ccdbg-io.c b/lib/ccdbg-io.c index e5e85e43..3606c57c 100644 --- a/lib/ccdbg-io.c +++ b/lib/ccdbg-io.c @@ -25,6 +25,7 @@ #endif static uint32_t cc_clock_us = CC_CLOCK_US; +static uint32_t cc_reset_us = CC_RESET_US; void ccdbg_set_clock(uint32_t us) @@ -41,6 +42,17 @@ ccdbg_half_clock(struct ccdbg *dbg) nanosleep(&req, &rem); } +void +ccdbg_wait_reset(struct ccdbg *dbg) +{ + struct timespec req, rem; + + ccdbg_sync_io(dbg); + req.tv_sec = (cc_reset_us) / 1000000; + req.tv_nsec = ((cc_reset_us) % 1000000) * 1000; + nanosleep(&req, &rem); +} + struct ccdbg * ccdbg_open(void) { diff --git a/lib/ccdbg.h b/lib/ccdbg.h index 037d8ff5..8bc9444a 100644 --- a/lib/ccdbg.h +++ b/lib/ccdbg.h @@ -37,6 +37,12 @@ #define CC_RESET_N 0x4 #define CC_CLOCK_US (0) +/* Telemetrum has a 10k pull-up to 3.3v, a 0.001uF cap to ground + * and a 2.7k resistor to the reset line. This takes about 6us + * to settle, so we'll wait longer than that after changing the reset line + */ +#define CC_RESET_US (12) + /* 8051 instructions */ #define NOP 0x00 @@ -264,6 +270,9 @@ ccdbg_set_clock(uint32_t us); void ccdbg_half_clock(struct ccdbg *dbg); +void +ccdbg_wait_reset(struct ccdbg *dbg); + int ccdbg_write(struct ccdbg *dbg, uint8_t mask, uint8_t value); |