implement vsync irq-based frame counter

[megadrive.git] / main.c

diff --git a/main.c b/main.c
index 72b3acd..a3062c2 100644 (file)
--- a/main.c
+++ b/main.c
@@ -17,6 +17,8 @@ static struct {
        uint32_t stream_enable:1;
        uint32_t stream_started:1;
        uint32_t stream_received:1;
+       uint32_t use_readinc:1;
+       uint32_t frame_cnt;
        uint32_t edge_cnt;
        uint32_t i;
        uint32_t o;
@@ -42,32 +44,74 @@ void yield(void)
 {
 }
 
-static void my_portb_isr(void)
+static void portb_isr_fixed(void)
 {
        uint32_t isfr, th;
 
-       //printf("irq, GPIOB_PDIR: %08x\n", GPIOB_PDIR);
+       isfr = PORTB_ISFR;
+       PORTB_ISFR = isfr;
+       th = (GPIOB_PDIR >> CORE_PIN0_BIT) & 1;
+
+       GPIOD_PDOR = g.fixed_state[th];
+       g.edge_cnt++;
+}
+
+static void portb_isr_readinc(void)
+{
+       uint32_t isfr, th;
 
        isfr = PORTB_ISFR;
        PORTB_ISFR = isfr;
        th = (GPIOB_PDIR >> CORE_PIN0_BIT) & 1;
 
-       if (g.stream_started) {
-               GPIOD_PDOR = g.stream[g.o][th];
-               if (th) {
-                       g.o = (g.o + 1) & STREAM_BUF_MASK;
-                       if (g.o == g.i) {
-                               g.stream_started = 0;
-                               g.stream_enable = 0;
-                       }
-               }
-       }
-       else {
-               GPIOD_PDOR = g.fixed_state[th];
+       GPIOD_PDOR = g.stream[g.o][th];
+       if (th) {
+               g.o = (g.o + 1) & STREAM_BUF_MASK;
+               if (g.o == g.i)
+                       // done
+                       attachInterruptVector(IRQ_PORTB, portb_isr_fixed);
+               g.frame_cnt++;
        }
        g.edge_cnt++;
 }
 
+static void portb_isr_read(void)
+{
+       uint32_t isfr, th;
+
+       isfr = PORTB_ISFR;
+       PORTB_ISFR = isfr;
+       th = (GPIOB_PDIR >> CORE_PIN0_BIT) & 1;
+
+       GPIOD_PDOR = g.stream[g.o][th];
+       g.edge_cnt++;
+}
+
+static void portc_isr_nop(void)
+{
+       uint32_t isfr;
+
+       isfr = PORTC_ISFR;
+       PORTC_ISFR = isfr;
+}
+
+// /vsync starts at line 235/259 (ntsc/pal), just as vcounter jumps back
+// we care when it comes out (/vsync goes high) after 3 lines at 238/262
+static void portc_isr_frameinc(void)
+{
+       uint32_t isfr;
+
+       isfr = PORTC_ISFR;
+       PORTC_ISFR = isfr;
+
+       g.o = (g.o + 1) & STREAM_BUF_MASK;
+       if (g.o == g.i) {
+               attachInterruptVector(IRQ_PORTB, portb_isr_fixed);
+               attachInterruptVector(IRQ_PORTC, portc_isr_nop);
+       }
+       g.frame_cnt++;
+}
+
 static void udelay(uint32_t us)
 {
        uint32_t start = micros();
@@ -144,7 +188,17 @@ static void do_start_seq(void)
                return;
        }
 
+       __disable_irq();
        g.stream_started = 1;
+       if (g.use_readinc) {
+               attachInterruptVector(IRQ_PORTB, portb_isr_readinc);
+               attachInterruptVector(IRQ_PORTC, portc_isr_nop);
+       }
+       else {
+               attachInterruptVector(IRQ_PORTB, portb_isr_read);
+               attachInterruptVector(IRQ_PORTC, portc_isr_frameinc);
+       }
+       __enable_irq();
 }
 
 static int get_space(void)
@@ -163,14 +217,21 @@ static void do_usb(void *buf)
                memcpy(g.fixed_state, pkt->data, sizeof(g.fixed_state));
                break;
        case PKT_STREAM_ENABLE:
+               __disable_irq();
+               /* wait for start from MD */
                g.stream_enable = 1;
                g.stream_started = 0;
                g.stream_received = 0;
+               g.use_readinc = pkt->start.use_readinc;
                g.i = g.o = 0;
+               g.frame_cnt = 0;
+               attachInterruptVector(IRQ_PORTB, portb_isr_fixed);
+               attachInterruptVector(IRQ_PORTC, portc_isr_nop);
+               __enable_irq();
                break;
        case PKT_STREAM_END:
                g.stream_received = 1;
-               printf("end of data\n");
+               printf("end of stream\n");
                break;
        case PKT_STREAM_DATA:
                g_i = g.i;
@@ -209,17 +270,20 @@ int main(void)
 
        printf("starting, rawhid: %d\n", usb_rawhid_available());
 
-       // md pin   th tr tl  r  l  d  u
+       // md pin   th tr tl  r  l  d  u vsync
        // md bit*   6  5  4  3  2  1  0
-       // t bit   b16 d5 d4 d3 d2 d1 d0
-       // t pin     0 20  6  8  7 14  2
+       // t bit   b16 d5 d4 d3 d2 d1 d0    c6
+       // t pin     0 20  6  8  7 14  2    11
        // * - note: tl/tr mixed in most docs
        pinMode(0, INPUT);
-       attachInterrupt(0, my_portb_isr, CHANGE);
-       attachInterruptVector(IRQ_PORTB, my_portb_isr);
+       attachInterrupt(0, portb_isr_fixed, CHANGE);
+       attachInterruptVector(IRQ_PORTB, portb_isr_fixed);
+       pinMode(11, INPUT);
+       attachInterrupt(11, portc_isr_nop, RISING);
+       attachInterruptVector(IRQ_PORTC, portc_isr_nop);
 
-       // NVIC_SET_PRIORITY(104, 0); // portb
-       NVIC_SET_PRIORITY(IRQ_PORTB, 0); // portb
+       NVIC_SET_PRIORITY(IRQ_PORTB, 0);
+       NVIC_SET_PRIORITY(IRQ_PORTC, 16);
 
        pinMode( 2, OUTPUT);
        pinMode(14, OUTPUT);
@@ -232,9 +296,11 @@ int main(void)
        pinMode(13, OUTPUT);
 
        // CORE_PIN0_PORTSET CORE_PIN0_BITMASK PORTB_PCR16
+       printf("GPIOB PDDR, PDIR: %08x %08x\n", GPIOB_PDIR, GPIOB_PDDR);
        printf("GPIOC PDDR, PDIR: %08x %08x\n", GPIOC_PDIR, GPIOC_PDDR);
        printf("GPIOD PDDR, PDIR: %08x %08x\n", GPIOD_PDIR, GPIOD_PDDR);
        printf("PORTB_PCR16: %08x\n", PORTB_PCR16);
+       printf("PORTC_PCR6:  %08x\n", PORTC_PCR6);
 
        asm("mrs %0, BASEPRI" : "=r"(ret));
        printf("BASEPRI: %d\n", ret);
@@ -248,6 +314,8 @@ int main(void)
                       && get_space() > sizeof(pkt.data) / STREAM_EL_SZ)
                {
                        pkt.type = PKT_STREAM_REQ;
+                       pkt.req.frame = g.frame_cnt;
+
                        ret = usb_rawhid_send(&pkt, 1000);
                        if (ret != sizeof(pkt)) {
                                printf("send STREAM_REQ: %d\n", ret);