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rasProject_01 / weSweetHome
R. 240
process control / RasPi software by weinert-automation
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rasProject_01 / weSweetHome
R. 240
process control / RasPi software by weinert-automation
|
DCF77 decoder on Raspberry Pi. More...
#include "weDCF77.h"Functions | |
| void | dcf77receiveRec (int pi, unsigned gpio, unsigned level, uint32_t tick) |
| DCF77 receive recorder. More... | |
| int | dcf77receiveRecDeregister (void) |
| DCF77 receive function de-registration. More... | |
| int | dcf77receiveRecRegister (void) |
| DCF77 receive recorder registration. More... | |
| durDiscrPointData_t * | disc5 (durDiscrPointData_t table[], uint32_t const value) |
| Discriminating a value. More... | |
| uint32_t | initDCF77io () |
| Initialise the DCF77 signal input GPIO / pin. More... | |
| void | setReceiver (int const level) |
| Set receiver On control. More... | |
Variables | |
| unsigned | curBCDnum |
| Number decoded from period sequence parts. More... | |
| int | dcf77callbackID |
| PiGpioD's call back ID for receiver function. | |
| unsigned | dcf77glitch |
| DCF77 input's glitch filter time setting. More... | |
| unsigned | dcf77inp |
| Input GPIO for the DCF77 receiver's AM signal. More... | |
| unsigned | dcf77invInp |
| Inverted DCF77 receiver's signal. More... | |
| unsigned | dcf77lastLevel |
| Last DCF77 modulation level. More... | |
| unsigned | dcf77PUD |
| DCF77 input's pull resistor setting. More... | |
| unsigned | dcf77recCnt |
| Control output GPIO of the DCF77 receiver's control. More... | |
| unsigned | dcf77recCntInv |
| Receiver On control inverted. More... | |
| dcf77recPerData_t | dfc77actRecPer |
| The actual respectively last modulation period data received. | |
| dcf77recPerData_t | dfc77ringBrecPer [DCF77RINGbufWRAP+1] |
| Ring buffer of modulation period data received. | |
| uint8_t | dfc77ringBrecWInd |
| Modulation period data received ring buffer write index. | |
| char | lastSysClk [14] |
| The system time for low AM as text hh:mm:ss. More... | |
| unsigned const | num02st [] |
| see numBCDinit, values 0 2 | |
| unsigned const | num04st [] |
| see numBCDinit, values 0 4 | |
| unsigned const | num08st [] |
| see numBCDinit, values 0 8 | |
| unsigned const | num10st [] |
| see numBCDinit, values 0 10 | |
| unsigned const | num20st [] |
| see numBCDinit, values 0 20 | |
| unsigned const | num40st [] |
| see numBCDinit, values 0 40 | |
| unsigned const | num80st [] |
| see numBCDinit, values 0 80 | |
| unsigned const | numBCDinit [] |
| Initialisation or least significant BDC digit for modulation time. More... | |
| durDiscrPointData_t | perDiscH [5] |
| Discrimination values for the modulation period. More... | |
| durDiscrPointData_t | perDiscP [5] |
| Discrimination values for the modulation period. More... | |
| durDiscrPointData_t * | perDiscUsed |
| Discrimination values for the modulation period used. More... | |
| durDiscrPointData_t | timDiscH [5] |
| Discrimination values for the 15% modulation time. More... | |
| durDiscrPointData_t | timDiscHs [5] |
| Discrimination values for the 15% modulation time. More... | |
| durDiscrPointData_t | timDiscP [5] |
| Discrimination values for the 15% modulation time. More... | |
| durDiscrPointData_t * | timDiscUsed |
| Discrimination values for the 15% modulation time. More... | |
DCF77 decoder on Raspberry Pi.
Revision history
This is a supplementary basic library to handle the signal of a DCF77 receiver. In the case of AM (amplitude) modulation a 1 (high) at the signal input means 15% amplitude and a 0 (low) 100% respectively full amplitude. The other way round is marked as dcf77invInp.
| void setReceiver | ( | int const | level | ) |
| uint32_t initDCF77io | ( | ) |
Initialise the DCF77 signal input GPIO / pin.
The signal input dcf77inp and control output dcf77recCnt are initialised.
| void dcf77receiveRec | ( | int | pi, |
| unsigned | gpio, | ||
| unsigned | level, | ||
| uint32_t | tick | ||
| ) |
DCF77 receive recorder.
This is a pigpiod callback function for an AM DCF77 receiver. It does no filtering nor decoding. It just fills dfc77actRecPer for the current modulation period and stores it in dfc77ringBrecPer when the next period begins.
| int dcf77receiveRecRegister | ( | void | ) |
DCF77 receive recorder registration.
This function registers the call back function dcf77receiveRec with the PiGpioDaemon.
| int dcf77receiveRecDeregister | ( | void | ) |
DCF77 receive function de-registration.
This function de-registers the call back registered under dcf77callbackID.
| durDiscrPointData_t * disc5 | ( | durDiscrPointData_t | table[], |
| uint32_t const | value | ||
| ) |
Discriminating a value.
In a discrimination table / array of length 5 this function returns a pointer to the highest table entry with value >= table[i].v
The entry returned must be treated as const.
| table | discrimination table of length 5. With other lengths the function will fail. Must not be null. |
| value | the number to be discriminated |
| unsigned dcf77recCnt |
Control output GPIO of the DCF77 receiver's control.
This output, if used and connected, controls the amplitude modulation (AM) receiver's control (On/Off) signal. If there is no such output (PINig) The receiver either has no such control input or it is tight to On.
default PINig; see also dcf77recCntInv, setReceiver()
| unsigned dcf77recCntInv |
Receiver On control inverted.
The receiver control output (dcf77recCnt), when used, would be set to ON (Hi, 3V) to enable the receiver. And it would be set OFF for a short time to reset a panicing or inactive receiver.
If dcf77recCntInv is true it is the other way round. The common receiver chips control input is low active, hence inverted and dcf77recCntInv should be true. As an open collector stage near the Pi for this output is highly recommended, nevertheless the default value is FALSE.
default FALSE; see also dcf77recCnt, setReceiver()
| unsigned dcf77inp |
Input GPIO for the DCF77 receiver's AM signal.
This is the amplitude modulation (AM) level signal; the level is either 100% or 15% (for 100 or 200ms).
default PIN08; see also dcf77invInp, dcf77PUD, dcf77glitch
| unsigned dcf77invInp |
| unsigned dcf77PUD |
DCF77 input's pull resistor setting.
default: PI_PUD_KEEP; see also dcf77inp
| unsigned dcf77glitch |
DCF77 input's glitch filter time setting.
The value for pigpiod's input filter time in μs. The allowed range is 0 ... 30000. The filtering only works for pins sampled by a callback function (like dcf77receiveRec()).
default: 0; glitch filter off; see also dcf77inp
| unsigned dcf77lastLevel |
Last DCF77 modulation level.
ON means 15% modulation amplitude; i.e. the signal.
OFF means 100% amplitude; i.e. just the 77,5 kHz carrier.
This variable is set by the receiver (callback) function and must not be modified by user software.
| char lastSysClk[14] |
The system time for low AM as text hh:mm:ss.
This textual time stamp is taken at the start of the AM (15%) tick respectively when the callback function is executed for this event.
| durDiscrPointData_t timDiscP[5] |
Discrimination values for the 15% modulation time.
This is an array of fixed length 5 to discriminate dcf77recPerData_t::tim values.
The only good outcomes of discrimination are indices (durDiscrPointData_t::i) 1 and 3 meaning a recognisable bit 0 respectively 1.
Hint: index bit 0 set means no error.
Hint2: Name ending with P means designed for low grade AM receiver modules. The criteria values are extended quite far for guessing the meaning in the presence of timing faults. Spikes would have to be filtered in a next stage by combining two to four faulty periods in one. Low grade receivers would be not usable without such (complex) filter algorithms.
| durDiscrPointData_t perDiscP[5] |
Discrimination values for the modulation period.
This is an array of fixed length 5 to discriminate dcf77recPerData_t::per values.
The only good outcomes of discrimination are indices (durDiscrPointData_t::i) 1 and 3 meaning an acceptable 1s respectively 2s period.
Hint: See hints at timDiscP.
| durDiscrPointData_t timDiscH[5] |
Discrimination values for the 15% modulation time.
This is an array of fixed length 5 to discriminate dcf77recPerData_t::tim values.
The good outcomes have indices (durDiscrPointData_t::i) 1 and 3 meaning a recognisable bit 0 (FALSE) respectively 1 (TRUE).
Hint: index bit 0 set means no error.
Hint2: Name ending with H means designed for high grade AM receiver modules with virtually no timing faults or spikes. Hence, the criteria values are relatively tight, to recognise EMI or short outages as such. Trying to interpret those with filter algorithms may not be worth the effort with good receivers.
Hint3: Some lower grade AM receiver modules were enhanced with an inverting NPN transistor stage with a low capacity collector to ground capacitor implemented by three meter shielded signal and supply cable. This adding of a simple inverter stage is recommended for all receiver modules not equipped with an open collector (OC) output stage. And for some of them its a necessary filter stage.
| durDiscrPointData_t timDiscHs[5] |
Discrimination values for the 15% modulation time.
This is an array of fixed length 5 to discriminate dcf77recPerData_t::tim values.
It is the same as timDiscH except for the extra note/hint 4.
Hint 4: The price for turning bad to good receivers by the circuit of Hint 3 was good pulses shortened well below 100 respectively 200 ms. Therefore this table allows for such shortened pulses noting it by the name's suffix s.
| durDiscrPointData_t perDiscH[5] |
Discrimination values for the modulation period.
This is an array of fixed length 5 to discriminate dcf77recPerData_t::per values.
The only good outcomes of discrimination are indices (durDiscrPointData_t::i) 1 and 3 meaning an acceptable 1s respectively 2s period.
Hint: See hints at timDiscHs.
| durDiscrPointData_t* perDiscUsed |
Discrimination values for the modulation period used.
This is a pointer to an array of fixed length 5 to discriminate dcf77recPerData_t::per values. The purpose is to hold the current filter values.
default: perDiscP
| durDiscrPointData_t* timDiscUsed |
Discrimination values for the 15% modulation time.
This is a pointer to an array of fixed length 5 to discriminate dcf77recPerData_t::per values. The purpose is to hold the current filter values.
default: timDiscP
| unsigned curBCDnum |
Number decoded from period sequence parts.
This variable holds the (current) number evaluated by considering the sequence of disc5(timDiscUsed, modulationTime) in question. Here, with number sequences a false (level 1, 'F') means 0 and a true (level 3, 'T') means 1, 2, 4, 8, 10, 20, 40 or 80 depending on the place within the BCD coded number. Any other level (0 spike, 3 undef, 4 error) invalidates the whole number.
Values 0..99 (max year) are OK, a value above means an error in the sequence.
| unsigned const numBCDinit[] |
Initialisation or least significant BDC digit for modulation time.
For the durDiscrPointData_t i value as index this constant array yields 0 or 1 — or respectively 2, 4 , 8, 10, 20, 40, 60 and 80 — for valid times and a high error value else.
The rationale is just adding up yields a correct value in the BCD range of 0 .. 99 while any higher value means error.
1.9.5