Code:
// https://forum.pjrc.com/threads/71193-Teensy-4-Measuring-multiple-frequencies
// Timer Pin Pad ALT input mux
// QuadTimer4_1 6 B0_10 1
// QuadTimer4_2 9 B0_11 1
// QuadTimer1_0 10 B0_00 1
// QuadTimer1_2 11 B0_02 1
// QuadTimer1_1 12 B0_01 1
// QuadTimer2_0 13 B0_03 1 IOMUXC_QTIMER2_TIMER0_SELECT_INPUT=1
// QuadTimer3_2 14 AD_B1_02 1 IOMUXC_QTIMER3_TIMER2_SELECT_INPUT=1
// QuadTimer3_3 15 AD_B1_03 1 IOMUXC_QTIMER3_TIMER3_SELECT_INPUT=1
// QuadTimer3_1 18 AD_B1_01 1 IOMUXC_QTIMER3_TIMER1_SELECT_INPUT=1
// QuadTimer3_0 19 AD_B1_00 1 IOMUXC_QTIMER3_TIMER0_SELECT_INPUT=1
#define GATE_INTERVAL 2000 // microseconds for each gate interval
#define GATE_ACCUM 100 // number of intervals to accumulate
#define MULT_FACTOR 5 // multiply to get Hz output
typedef struct {
IMXRT_TMR_t *timer;
int timerchannel;
int pin;
int pinconfig;
volatile uint32_t *inputselectreg;
int inputselectval;
} timerinfo_t;
const timerinfo_t timerlist[] = {
// Timer Ch Pin Alt Input Select
{&IMXRT_TMR4, 1, 6, 1, NULL, 0},
{&IMXRT_TMR4, 2, 9, 1, NULL, 0},
{&IMXRT_TMR1, 0, 10, 1, NULL, 0},
{&IMXRT_TMR1, 2, 11, 1, NULL, 0},
{&IMXRT_TMR1, 1, 12, 1, NULL, 0},
{&IMXRT_TMR2, 0, 13, 1, &IOMUXC_QTIMER2_TIMER0_SELECT_INPUT, 1},
{&IMXRT_TMR3, 2, 14, 1, &IOMUXC_QTIMER3_TIMER2_SELECT_INPUT, 1},
{&IMXRT_TMR3, 3, 15, 1, &IOMUXC_QTIMER3_TIMER3_SELECT_INPUT, 1},
{&IMXRT_TMR3, 1, 18, 1, &IOMUXC_QTIMER3_TIMER1_SELECT_INPUT, 0},
{&IMXRT_TMR3, 0, 19, 1, &IOMUXC_QTIMER3_TIMER0_SELECT_INPUT, 1},
// TODO: can 6 more be used with XBAR1 and GPR6 ?
};
#define NUM_TIMERS (sizeof(timerlist) / sizeof(timerinfo_t))
// gate interval interrupt deposits data here
volatile bool count_update = false;
volatile uint32_t count_output[NUM_TIMERS];
uint16_t read_count(unsigned int n) {
static uint16_t prior[NUM_TIMERS];
if (n >= NUM_TIMERS) return 0;
uint16_t count = (timerlist[n].timer)->CH[timerlist[n].timerchannel].CNTR;
uint16_t inc = count - prior[n];
prior[n] = count;
return inc;
}
void gate_timer() {
static unsigned int count = 0;
static uint32_t accum[NUM_TIMERS];
for (unsigned int i=0; i < NUM_TIMERS; i++) {
accum[i] += read_count(i);
}
if (++count >= GATE_ACCUM) {
for (unsigned int i=0; i < NUM_TIMERS; i++) {
count_output[i] = accum[i];
accum[i] = 0;
}
count_update = true;
count = 0;
}
}
void setup() {
// create some test frequencies
analogWriteFrequency(0, 3000000);
analogWriteFrequency(1, 15000000);
analogWriteFrequency(2, 220000);
analogWriteFrequency(4, 10000000);
analogWriteFrequency(5, 455000);
analogWrite(0, 128);
analogWrite(1, 128);
analogWrite(2, 128);
analogWrite(4, 128);
analogWrite(5, 128);
// Welcome message
Serial.begin(9600);
Serial.print("FreqCountMany, maximum frequency = ");
Serial.print(65535.0 / ((double)GATE_INTERVAL), 3);
Serial.println(" MHz");
// turn on clock to all quad timers
CCM_CCGR6 |= CCM_CCGR6_QTIMER1(CCM_CCGR_ON) | CCM_CCGR6_QTIMER2(CCM_CCGR_ON)
| CCM_CCGR6_QTIMER3(CCM_CCGR_ON) | CCM_CCGR6_QTIMER4(CCM_CCGR_ON);
// configure all counting timers
for (unsigned int i=0; i < NUM_TIMERS; i++) {
IMXRT_TMR_t *timer = timerlist[i].timer;
int ch = timerlist[i].timerchannel;
timer->CH[ch].CTRL = 0;
timer->CH[ch].CNTR = 0;
timer->CH[ch].LOAD = 0;
timer->CH[ch].COMP1 = 65535;
timer->CH[ch].CMPLD1 = 65535;
timer->CH[ch].SCTRL = 0;
timer->CH[ch].CTRL = TMR_CTRL_CM(1) | TMR_CTRL_PCS(ch) | TMR_CTRL_LENGTH;
int pin = timerlist[i].pin;
*portConfigRegister(pin) = timerlist[i].pinconfig;
if (timerlist[i].inputselectreg) {
*timerlist[i].inputselectreg = timerlist[i].inputselectval;
}
}
// start gate interval timer
static IntervalTimer t;
t.begin(gate_timer, GATE_INTERVAL);
}
void loop() {
if (count_update) {
for (unsigned int i=0; i < NUM_TIMERS; i++) {
Serial.printf("%8u ", count_output[i] * MULT_FACTOR);
}
Serial.println();
count_update = 0;
}
}
Signal inputs are meant to be on pins 6, 9, 10, 11, 12, 13, 14, 15, 18, 19.
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Originally Posted by KurtE
