Below is the readme file, to read the last version, directly go to :

https://github.com/tbarbette/picdomotic

PIC Domotic station

PIC program for a domotic station controlling two temperature sensors, multiple relay, a USB port (for power only) and connected to a PC using UART to receive its instructions.

It uses a PIC18F23K20 but should work on most of them. The PC sends simple commandes through /dev/ttyUSB0 like “A 32” to enable the device 32, or “E 32” to disable it. “T” to get temperature, … See the source code in main.c.

This is MPLAB X IDE project. The only usefull file is in fact main.c, the rest is auto-generated, but I include them if someone would want to directly program the binaries, for example.

Technology used

If you’re looking for sample code, you may find here how to :

• Use the UART to communicate with a PC (UART is connected to a “uart usb” module very cheaped that you can find on ebay for example) .
• Use the watchdog timer to ensure a device reset if something goes wrong
• Use Brown-out to jump to do an interrupt and do “something” (blink in my case) if the voltage goes below some threshold
• Use the ADC to read the temperature given by two LM35
• Read/write to eeprom
• Control a 5V relay board with a 3.3V relay board using NPN Transistors (when I’ll add the schematic though)

The python script used to manage the PIC controller is available athttps://github.com/tbarbette/monitoring/blob/master/scripts/relay.py and a small HTTP server allowing you to remotely control it is available athttps://github.com/tbarbette/monitoring/blob/master/scripts/server.py

The post PIC Domotic station appeared first on Tom Barbette.

Using the eeprom is as simple as these two commands :

[code lang=”c”]EEPROM_READ(addr)
EEPROM_WRITE(addr,value)
[/code]

A little example (reading from the USART a value and putting it in the EEPROM address 0x00)

[code]
while (!DataRdyUSART());
char data = ReadUSART();
EEPROM_WRITE(0x00,data);
[/code]

Note that theses header are defined in the standard xc8 header which will include (or , …) or High Tech C headers if you come from the past :

[code lang=”c”]
// MACROS for EEPROM Access
/* macro versions of EEPROM read and write */

/* NOTE WELL:
EEPROM_READ() is NOT safe to use immediately after any
write to EEPROM, as it does NOT wait for WR to clear. This is by
design, to allow minimal code size if a sequence of reads is
desired. To guarantee uncorrupted writes insert
while(WR)continue;
before calling EEPROM_READ().
*/

#if _EEPROMSIZE > 0 && defined(_PLIB)
#define EEPROM_READ(addr) Read_b_eep(addr)
#define eeprom_read(addr) Read_b_eep(addr)
#else
#define EEPROM_READ(addr) 0 // Added only for code portability
#define eeprom_read(addr) 0
#endif

#if _EEPROMSIZE > 0 && defined(_PLIB)
#define EEPROM_WRITE(addr, value) (Busy_eep(), Write_b_eep(addr,value))
#define eeprom_write(addr, value) (Busy_eep(), Write_b_eep(addr,value))
#else
#define EEPROM_WRITE(addr, value) // Added only for code portability
#define eeprom_write(addr, value)
#endif
[/code]

The post Read and write PIC EEPROM appeared first on Tom Barbette.