support new board (fpv motherboard v1)

[protos/rc_servos.git] / main.c

diff --git a/main.c b/main.c
index a27bf10..ad0af05 100644 (file)
--- a/main.c
+++ b/main.c
@@ -1,4 +1,5 @@
 #include <aversive.h>
+#include <aversive/wait.h>
 
 struct servo {
        uint8_t bit;
@@ -7,33 +8,122 @@ struct servo {
 
 static struct servo servo_table[] = {
        {
-               .bit = 0,
-               .command = 0,
+               .bit = 2,
+               .command = 300,
+       },
+       {
+               .bit = 3,
+               .command = 700,
        },
        {
-               .bit = 1,
+               .bit = 4,
                .command = 512,
        },
        {
-               .bit = 2,
-               .command = 1023,
+               .bit = 5,
+               .command = 512,
+       },
+       {
+               .bit = 6,
+               .command = 512,
+       },
+       {
+               .bit = 7,
+               .command = 512,
        },
 };
-
-static volatile uint8_t rxbuf[16];
-register uint8_t rxlen asm("r2");
-register uint8_t done asm("r3");
-register uint8_t portval asm("r4");
+#define NB_SERVO (sizeof(servo_table)/sizeof(*servo_table))
+
+static volatile uint8_t bypass;
+static volatile uint8_t done;
+static volatile uint8_t portval;
+static volatile uint8_t rxidx;
+
+#define BYPASS_ENABLE 14
+#define BYPASS_DISABLE 15
+
+#define LED_ON() do { PORTB |= 0x02; } while(0)
+#define LED_OFF() do { PORTB &= ~0x02; } while(0)
+
+/*
+ * SPI protocol:
+ *
+ * A command is stored on 2 bytes. The first one has its msb to 0, and the
+ * second one to 1. The first received byte contains the command number, and the
+ * msb of the servo value. The second byte contains the lsb of the servo value.
+ *
+ * Commands 0 to NB_SERVO are to set the value of servo.
+ * Command 14 is to enable bypass mode.
+ * Command 15 is to disable bypass mode.
+ */
+static volatile union {
+       uint8_t u8;
+       struct {
+               /* inverted: little endian */
+               uint8_t val_msb:3;
+               uint8_t cmd_num:4;
+               uint8_t zero:1;
+       };
+} byte0;
+
+static volatile union {
+       uint8_t u8;
+       struct {
+               /* inverted: little endian */
+               uint8_t val_lsb:7;
+               uint8_t one:1;
+       };
+} byte1;
 
 SIGNAL(TIMER1_COMPA_vect)
 {
-       PORTC = portval;
+       PORTD = portval;
        TIMSK1 &= ~_BV(OCIE1A);
        done = 1;
 }
 
 static void poll_spi(void)
 {
+       uint8_t c;
+
+       /* reception complete ? */
+       if (!(SPSR & (1<<SPIF)))
+               return;
+
+       c = SPDR;
+       if ((rxidx == 0) && (c & 0x80)) {
+               rxidx = 0;
+               return; /* drop */
+       }
+       if ((rxidx == 1) && ((c & 0x80) == 0)) {
+               rxidx = 0;
+               return; /* drop */
+       }
+
+       if (rxidx == 0) {
+               byte0.u8 = c;
+       }
+       else {
+               uint16_t val;
+
+               byte1.u8 = c;
+
+               /* process command */
+
+               if (byte0.cmd_num < NB_SERVO) {
+                       val = (uint16_t)byte0.val_msb << 7;
+                       val += byte1.val_lsb;
+                       servo_table[byte0.cmd_num].command = val;
+               }
+               else if (byte0.cmd_num == BYPASS_ENABLE) {
+                       bypass = 1;
+               }
+               else if (byte0.cmd_num == BYPASS_DISABLE) {
+                       bypass = 0;
+               }
+       }
+
+       rxidx ^= 1;
 }
 
 static void load_timer_at(uint16_t t)
@@ -69,8 +159,20 @@ int main(void)
        uint8_t i;
        uint8_t t, diff;
 
-       DDRB = 0x20;
-       DDRC = 0x7;
+       /* LED */
+       DDRB = 0x02;
+
+#if 0 /* LED debug */
+       while (1) {
+               LED_ON();
+               wait_ms(100);
+               LED_OFF();
+               wait_ms(100);
+       }
+#endif
+
+       /* servo outputs PD2-PD7 */
+       DDRD = 0xfc;
 
        /* start timer1 at clk/1 (8Mhz) */
        TCNT1 = 0;
@@ -80,11 +182,15 @@ int main(void)
        TCNT0 = 0;
        TCCR0B = _BV(CS02) | _BV(CS00);
 
+       /* enable spi (don't set unused MISO as output) */
+       SPCR = _BV(SPE);
+
        sei();
 
+       bypass = 0;
        while (1) {
                t = TCNT0;
-               for (i = 0; i < sizeof(servo_table)/sizeof(*servo_table); i++) {
+               for (i = 0; i < NB_SERVO; i++) {
                        do_one_servo(&servo_table[i]);
                }
                /* wait 20 ms */
@@ -94,6 +200,13 @@ int main(void)
                                break;
                        poll_spi();
                }
+               /* bypass mode */
+               while (bypass == 1) {
+                       LED_ON();
+                       PORTD = (PINC & 0x3f) << 2;
+                       poll_spi();
+               }
+               LED_OFF();
        }
 
        return 0;