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Merge pull request #2617 from nvx/fix_ssp_clk_tc2_initial_reset_rollover

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fix ssp_clk sometimes resetting to 0 shortly after being started or reset
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Iceman 2024-11-04 13:28:46 +01:00 • committed by GitHub
commit 3402e7f5a8
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1 changed files with 4 additions and 4 deletions
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8
common_arm/ticks.c
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@ -149,7 +149,8 @@ void StartCountSspClk(void) {
| AT91C_TC_WAVE // Waveform Mode | AT91C_TC_WAVE // Waveform Mode
| AT91C_TC_WAVESEL_UP // just count | AT91C_TC_WAVESEL_UP // just count
| AT91C_TC_ACPA_CLEAR // Clear TIOA0 on RA Compare | AT91C_TC_ACPA_CLEAR // Clear TIOA0 on RA Compare
| AT91C_TC_ACPC_SET; // Set TIOA0 on RC Compare | AT91C_TC_ACPC_SET // Set TIOA0 on RC Compare
| AT91C_TC_ASWTRG_SET; // Set TIOA0 on software trigger to trigger instant reset of TC2
AT91C_BASE_TC0->TC_RA = 1; // RA Compare value = 1; pulse width to TC2 AT91C_BASE_TC0->TC_RA = 1; // RA Compare value = 1; pulse width to TC2
AT91C_BASE_TC0->TC_RC = 0; // RC Compare value = 0; increment TC2 on overflow AT91C_BASE_TC0->TC_RC = 0; // RC Compare value = 0; increment TC2 on overflow
@ -191,8 +192,8 @@ void StartCountSspClk(void) {
// whenever the last three bits of our counter go 0, we can be sure to be in the middle of a frame transfer. // whenever the last three bits of our counter go 0, we can be sure to be in the middle of a frame transfer.
// (just started with the transfer of the 4th Bit). // (just started with the transfer of the 4th Bit).
// The high word of the counter (TC2) will not reset until the low word (TC0) overflows. // The high word of the counter (TC2) will not reset until the low word (TC0) clocks to process the external trigger.
// Therefore need to wait quite some time before we can use the counter. // Therefore may need to wait a little bit before we can use the counter.
while (AT91C_BASE_TC2->TC_CV > 0); while (AT91C_BASE_TC2->TC_CV > 0);
} }
void ResetSspClk(void) { void ResetSspClk(void) {
@ -336,4 +337,3 @@ void StopTicks(void) {
AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS; AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS;
AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS; AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;
} }