ESP32-PaxCounter/src/if482.cpp
2019-02-09 14:21:09 +01:00

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/* NOTE:
The IF482 Generator needs an high precise 1 Hz clock signal which cannot be
acquired in suitable precision on the ESP32 SoC itself. Additional clocking
hardware is required, ususally the clock signal is generated by external RTC or
GPS which can generate a precise time pulse signal (+/- 2ppm).
In this example code we use a Maxim DS3231 RTC chip, and configure the chips's
interrupt output pin as clock. The clock signal triggers an interrupt on the
ESP32, which controls the realtime output of IF482 telegram. This is why code in
IF482.cpp depends on code in RTCTIME.cpp.
*/
///////////////////////////////////////////////////////////////////////////////
/*
IF482 Generator to control clocks with IF482 telegram input (e.g. BÜRK BU190)
Example IF482 telegram: "OAL160806F170400"
IF482 Specification:
http://www.mobatime.com/fileadmin/user_upload/downloads/TE-112023.pdf
The IF 482 telegram is a time telegram, which sends the time and date
information as ASCII characters through the serial interface RS 232 or RS 422.
Communication parameters:
Baud rate: 9600 Bit/s
Data bits 7
Parity: even
Stop bit: 1
Jitter: < 50ms
Interface : RS232 or RS422
Synchronization: Telegram ends at the beginning of the second
specified in the telegram
Cycle: 1 second
Format of ASCII telegram string:
Byte Meaning ASCII Hex
1 Start of telegram O 4F
2 Monitoring* A 41
3 Time-Season** W/S/U/L 57 or 53
4 Year tens 0 .. 9 30 .. 39
5 Year unit 0 .. 9 30 .. 39
6 Month tens 0 or 1 30 or 31
7 Month unit 0 .. 9 30 .. 39
8 Day tens 0 .. 3 30 .. 33
9 Day unit 0 .. 9 30 .. 39
10 Day of week*** 1 .. 7 31 .. 37
11 Hours tens 0 .. 2 30 .. 32
12 Hours unit 0 .. 9 30 .. 39
13 Minutes tens 0 .. 5 30 .. 35
14 Minutes unit 0 .. 9 30 .. 39
15 Seconds tens 0 .. 5 30 .. 35
16 Seconds unit 0 .. 9 30 .. 39
17 End of telegram CR 0D
*) Monitoring:
With a correctly received time in the sender unit, the ASCII character 'A' is
issued. If 'M' is issued, this indicates that the sender was unable to receive
any time signal for over 12 hours (time is accepted with A and M).
**) Season:
W: Standard time,
S: Season time,
U: UTC time (not supported by all systems),
L: Local Time
***) Day of week:
not evaluated by model BU-190
*/
///////////////////////////////////////////////////////////////////////////////
#ifdef HAS_IF482
#ifdef HAS_DCF77
#error "You must define at most one of IF482 or DCF77"
#endif
#include "if482.h"
// Local logging tag
static const char TAG[] = "main";
#define IF482_FRAME_SIZE (17)
#define IF482_PULSE_DURATION (1000)
// select internal / external clock
#if defined RTC_INT && defined RTC_CLK
#define PPS RTC_CLK
#elif defined GPS_INT && defined GPS_CLK
#define PPS GPS_CLK
#else
#define PPS IF482_PULSE_DURATION
#endif
HardwareSerial IF482(2); // use UART #2 (note: #1 may be in use for serial GPS)
// initialize and configure IF482 Generator
int if482_init(void) {
// open serial interface
IF482.begin(HAS_IF482);
// start if482 serial output feed task
xTaskCreatePinnedToCore(if482_loop, // task function
"if482loop", // name of task
2048, // stack size of task
(void *)1, // parameter of the task
3, // priority of the task
&ClockTask, // task handle
0); // CPU core
assert(ClockTask); // has clock task started?
timepulse_init(PPS); // setup pulse
timepulse_start(); // start pulse
return 1; // success
} // if482_init
String IF482_Out(time_t tt) {
time_t t = myTZ.toLocal(tt);
char mon, buf[14], out[IF482_FRAME_SIZE];
switch (timeStatus()) { // indicates if time has been set and recently synced
case timeSet: // time is set and is synced
mon = 'A';
break;
case timeNeedsSync: // time had been set but sync attempt did not succeed
mon = 'M';
break;
default: // time not set, no valid time
mon = '?';
break;
} // switch
// do we have confident time/date?
if ((timeStatus() == timeSet) || (timeStatus() == timeNeedsSync))
snprintf(buf, sizeof(buf), "%02u%02u%02u%1u%02u%02u%02u", year(t) - 2000,
month(t), day(t), weekday(t), hour(t), minute(t), second(t));
else
snprintf(buf, sizeof(buf), "000000F000000"); // no confident time/date
// output IF482 telegram
snprintf(out, sizeof(out), "O%cL%s\r", mon, buf);
ESP_LOGD(TAG, "IF482 = %s", out);
return out;
}
void if482_loop(void *pvParameters) {
configASSERT(((uint32_t)pvParameters) == 1); // FreeRTOS check
TickType_t wakeTime;
const TickType_t timeOffset =
pdMS_TO_TICKS(IF482_OFFSET); // duration of telegram transmit
const TickType_t startTime = xTaskGetTickCount(); // now
sync_clock(now()); // wait until begin of a new second
BitsPending = true; // start blink in display
// take timestamp at moment of start of new second
const TickType_t shotTime = xTaskGetTickCount() - startTime - timeOffset;
// task remains in blocked state until it is notified by isr
for (;;) {
xTaskNotifyWait(
0x00, // don't clear any bits on entry
ULONG_MAX, // clear all bits on exit
&wakeTime, // receives moment of call from isr
portMAX_DELAY); // wait forever (missing error handling here...)
// select clock scale
#if (PPS == IF482_PULSE_DURATION) // we don't need clock rescaling
// wait until it's time to start transmit telegram for next second
vTaskDelayUntil(&wakeTime, shotTime); // sets waketime to moment of shot
IF482.print(IF482_Out(now() + 1));
#elif (PPS > IF482_PULSE_DURATION) // we need upclocking
for (uint8_t i = 1; i <= PPS / IF482_PULSE_DURATION; i++) {
vTaskDelayUntil(&wakeTime, shotTime); // sets waketime to moment of shot
IF482.print(IF482_Out(now() + 1));
}
#elif (PPS < IF482_PULSE_DURATION) // we need downclocking
IF482.print(IF482_Out(now() + 1));
vTaskDelayUntil(&wakeTime,
shotTime - PPS); // sets waketime to moment of shot
#endif
}
} // if482_loop()
#endif // HAS_IF482