Add servo pulse measurement program (unfinished)

firmware/pulse-measurement/makefile

@@ -0,0 +1,25 @@
+.PHONY: all
+all: pulse-measurement
+
+
+#############################################################################
+.PHONY: pulse-measurement
+pulse-measurement: pulse-measurement.hex
+
+pulse-measurement.hex: pulse-measurement.o servo-input.o uart-output.o
+ sdcc --use-non-free -mpic14 -p16f1825 -o $@ $^
+
+
+#############################################################################
+.c.o:
+ sdcc --use-non-free -mpic14 -p16f1825 -c $<
+
+
+clean :
+ $(RM) *.hex
+ $(RM) *.lst
+ $(RM) *.map
+ $(RM) *.cod
+ $(RM) *.o
+ $(RM) *.asm
+

firmware/pulse-measurement/pulse-measurement.c

@@ -0,0 +1,49 @@
+#include <pic16f1825.h>
+#include <stdint.h>
+
+static __code uint16_t __at (_CONFIG1) configword1 = _FOSC_INTOSC & _WDTE_OFF & _PWRTE_ON & _MCLRE_OFF & _CP_OFF & _CPD_OFF & _BOREN_OFF & _CLKOUTEN_OFF & _IESO_OFF & _FCMEN_OFF;
+static __code uint16_t __at (_CONFIG2) configword2 = _WRT_OFF & _PLLEN_OFF & _STVREN_OFF & _LVP_OFF; 
+
+extern void Init_input(void);
+extern void Read_input(void);
+extern void Init_output(void);
+extern void Output_result(void);
+
+
+/*****************************************************************************
+ Init_hardware()
+ 
+ Initializes all used peripherals of the PIC chip.
+ ****************************************************************************/
+static void Init_hardware(void) {
+ //-----------------------------
+ // Clock initialization
+ // FIXME: do 32 MHz HW
+ OSCCON = 0b01111010; // 4x PLL disabled, 16 MHz HF, Internal oscillator
+
+ //-----------------------------
+ // IO Port initialization
+ // FIXME: do 16F1825 ports
+ PORTA = 0;
+ LATA = 0;
+ ANSELA = 0;
+ TRISA = 0b11101000; // Make all ports that are not used for the motor input
+}
+
+
+/*****************************************************************************
+ main()
+ 
+ No introduction needed ... 
+ ****************************************************************************/
+void main(void) {
+ Init_hardware();
+ Init_output();
+ Init_input();
+
+ while (1) {
+ Read_input();
+ Output_result();
+ }
+}
+

firmware/pulse-measurement/servo-input.c

@@ -0,0 +1,53 @@
+#include <pic16f1825.h>
+
+
+/*****************************************************************************
+ Init_input()
+
+ Called once during start-up of the firmware. 
+ ****************************************************************************/
+void Init_input(void) {
+ // FIXME: Timer 1 at max speed; Single pulse gate mode
+
+ TMR1H = 0;
+ TMR1L = 0;
+}
+
+
+/*****************************************************************************
+ Read_input
+
+ Called once per mainloop to read the input signal.
+ This function shall set the global variable winch_mode depending on the 
+ state transition logic desired.
+ ****************************************************************************/
+void Read_input(void) {
+ // FIXME: use gate mode
+
+ ++TMR1H; 
+
+#if 0 
+ CCP1CON = 0b00000000; // Compare mode off
+
+ // Wait until servo signal is LOW 
+ // This ensures that we do not start in the middle of a pulse
+ while (RA5 != 0) ;
+
+ // Wait until servo signal is high; start of pulse
+ while (RA5 != 1) ;
+
+ // Start the time measurement
+ TMR1ON = 1; 
+
+ // Wait until servo signal is LOW again; end of pulse
+ while (RA5 != 0) ;
+
+ // Start the time measurement
+ TMR1ON = 0;
+
+ // Check if the measured pulse time is between 600 and 2500 us. If it is
+ // outside we consider it an invalid servo pulse and stop further execution.
+ //(TMR1H << 8) | TMR1L;
+#endif
+}
+

firmware/pulse-measurement/uart-output.c

@@ -0,0 +1,73 @@
+#include <pic16f1825.h>
+
+static unsigned char tx_value;
+
+static unsigned int val;
+
+#define FOSC 32 // Osc frequency in MHz
+#define BAUDRATE 38400 // Desired baudrate
+#define BRGH_VALUE 1 // Either 0 or 1
+#define SPBRG_VALUE (((10*FOSC*1000000/((64-(48*BRGH_VALUE))*BAUDRATE))+5)/10)-1
+
+static void UART_send(void);
+
+/*****************************************************************************
+ Init_output()
+
+ Called once during start-up of the firmware. 
+ ****************************************************************************/
+void Init_output(void) {
+ SPBRG = SPBRG_VALUE; // Baud Rate register, calculated by macro
+ BRGH = BRGH_VALUE;
+
+ SYNC=0; // Disable Synchronous/Enable Asynchronous
+ SPEN=1; // Enable serial port
+ TXEN=1; // Enable transmission mode
+ CREN=0; // Disable reception mode
+
+ TXREG = '\n';
+}
+
+
+/*****************************************************************************
+ Output_result()
+
+ FIXME: implement and document
+ ****************************************************************************/
+void Output_result(void) {
+ val = (TMR1H << 8) + TMR1L;
+
+ tx_value = val / 10000;
+ UART_send();
+ val = val % 10000;
+ tx_value = val / 1000;
+ UART_send();
+ val = val % 1000;
+ tx_value = val / 100;
+ UART_send();
+ val = val % 100;
+ tx_value = val / 10;
+ UART_send();
+ tx_value = val % 10;
+ UART_send();
+
+ tx_value = '\n';
+ UART_send();
+
+ for (val = 0; val < 1000; val++) {
+ ;
+ }
+
+}
+
+
+/*****************************************************************************
+ Send tx_value out via the UART
+ ****************************************************************************/
+void UART_send(void) {
+ /* Wait for TSR register being empty */
+ while (!TRMT);
+
+ TXREG = tx_value; 
+}
+