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SWD Timing: Enhance SWD high time with low speed loss. 

On F103 no high time < 80 ns and no low time < 100 ns was seen with a scope
This commit is contained in:
Uwe Bonnes 2020-09-02 18:11:57 +02:00 committed by UweBonnes
parent 2641291874
commit 58281ec232
1 changed files with 19 additions and 15 deletions
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34
src/platforms/common/swdptap.c
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@ -52,6 +52,8 @@ static void swdptap_turnaround(int dir)
SWDIO_MODE_FLOAT();
gpio_set(SWCLK_PORT, SWCLK_PIN);
gpio_set(SWCLK_PORT, SWCLK_PIN);
gpio_set(SWCLK_PORT, SWCLK_PIN);
gpio_set(SWCLK_PORT, SWCLK_PIN);
gpio_clear(SWCLK_PORT, SWCLK_PIN);
if(dir == SWDIO_STATUS_DRIVE)
SWDIO_MODE_DRIVE();
@ -68,6 +70,9 @@ static uint32_t swdptap_seq_in(int ticks)
int res;
res = gpio_get(SWDIO_PORT, SWDIO_PIN);
gpio_set(SWCLK_PORT, SWCLK_PIN);
gpio_set(SWCLK_PORT, SWCLK_PIN);
gpio_set(SWCLK_PORT, SWCLK_PIN);
gpio_set(SWCLK_PORT, SWCLK_PIN);
if (res)
ret |= index;
index <<= 1;
@ -90,20 +95,22 @@ static bool swdptap_seq_in_parity(uint32_t *ret, int ticks)
swdptap_turnaround(SWDIO_STATUS_FLOAT);
while (len--) {
gpio_clear(SWCLK_PORT, SWCLK_PIN);
bit = gpio_get(SWDIO_PORT, SWDIO_PIN);
gpio_set(SWCLK_PORT, SWCLK_PIN);
if (bit) {
gpio_set(SWCLK_PORT, SWCLK_PIN);
gpio_set(SWCLK_PORT, SWCLK_PIN);
if (bit)
res |= index;
}
index <<= 1;
gpio_clear(SWCLK_PORT, SWCLK_PIN);
}
gpio_clear(SWCLK_PORT, SWCLK_PIN);
int parity = __builtin_popcount(res);
bit = gpio_get(SWDIO_PORT, SWDIO_PIN);
gpio_set(SWCLK_PORT, SWCLK_PIN);
if (bit)
parity++;
else
gpio_set(SWCLK_PORT, SWCLK_PIN);
gpio_clear(SWCLK_PORT, SWCLK_PIN);
#ifdef DEBUG_SWD_BITS
for (int i = 0; i < len; i++)
@ -115,42 +122,39 @@ static bool swdptap_seq_in_parity(uint32_t *ret, int ticks)
static void swdptap_seq_out(uint32_t MS, int ticks)
{
int data = MS & 1;
#ifdef DEBUG_SWD_BITS
for (int i = 0; i < ticks; i++)
DEBUG("%d", (MS & (1 << i)) ? 1 : 0);
#endif
swdptap_turnaround(SWDIO_STATUS_DRIVE);
gpio_set_val(SWDIO_PORT, SWDIO_PIN, MS & 1);
while (ticks--) {
gpio_set_val(SWDIO_PORT, SWDIO_PIN, data);
gpio_clear(SWCLK_PORT, SWCLK_PIN);
MS >>= 1;
data = MS & 1;
gpio_set(SWCLK_PORT, SWCLK_PIN);
MS >>= 1;
gpio_set_val(SWDIO_PORT, SWDIO_PIN, MS & 1);
gpio_clear(SWCLK_PORT, SWCLK_PIN);
gpio_clear(SWCLK_PORT, SWCLK_PIN);
}
gpio_clear(SWCLK_PORT, SWCLK_PIN);
}
static void swdptap_seq_out_parity(uint32_t MS, int ticks)
{
int parity = __builtin_popcount(MS);
int data = MS & 1;
#ifdef DEBUG_SWD_BITS
for (int i = 0; i < ticks; i++)
DEBUG("%d", (MS & (1 << i)) ? 1 : 0);
#endif
swdptap_turnaround(SWDIO_STATUS_DRIVE);
gpio_set_val(SWDIO_PORT, SWDIO_PIN, data);
gpio_set_val(SWDIO_PORT, SWDIO_PIN, MS & 1);
MS >>= 1;
while (ticks--) {
data = MS & 1;
gpio_set(SWCLK_PORT, SWCLK_PIN);
gpio_set_val(SWDIO_PORT, SWDIO_PIN, data);
gpio_set_val(SWDIO_PORT, SWDIO_PIN, MS & 1);
MS >>= 1;
gpio_clear(SWCLK_PORT, SWCLK_PIN);
}
gpio_set_val(SWDIO_PORT, SWDIO_PIN, parity & 1);
gpio_clear(SWCLK_PORT, SWCLK_PIN);
gpio_set(SWCLK_PORT, SWCLK_PIN);
gpio_set(SWCLK_PORT, SWCLK_PIN);
gpio_set(SWCLK_PORT, SWCLK_PIN);
gpio_clear(SWCLK_PORT, SWCLK_PIN);