amiga: Synchronize amiga pin 34 to /MTR when motor-delay is configured.

Output ungated open-collector /DD density signal on JC.
Refs #354

Author: keirf

inc/util.h

@@ -173,6 +173,7 @@ unsigned int board_get_buttons(void);
 #define B_LEFT 1
 #define B_RIGHT 2
 #define B_SELECT 4
+void board_jc_set_mode(unsigned int mode);
 bool_t board_jc_strapped(void);
 
 /* Build info. */

src/floppy.c

@@ -34,6 +34,8 @@ static time_t prefetch_start_time;
 static uint32_t max_prefetch_us;
 
 struct drive;
+static always_inline void drive_change_pin(
+    struct drive *drv, uint8_t pin, bool_t assert);
 static always_inline void drive_change_output(
     struct drive *drv, uint8_t outp, bool_t assert);
 
@@ -130,13 +132,20 @@ static void drive_change_output(
 
 static void update_amiga_id(struct drive *drv, bool_t amiga_hd_id)
 {
-    /* Only for the Amiga interface, with hacked RDY (pin 34) signal. */
-    if (fintf_mode != FINTF_AMIGA)
+    /* JC and pin 34 are overridden only for the Amiga interface. */
+    if (fintf_mode != FINTF_AMIGA) {
+        drv->amiga_pin34 = FALSE;
+        board_jc_set_mode(GPI_pull_up);
         return;
+    }
 
+    /* JC and HDEN are set according to Amiga density. */
+    board_jc_set_mode(GPO_opendrain(_2MHz, amiga_hd_id));
     drive_change_output(drv, outp_hden, amiga_hd_id);
 
-    if (pin34 != outp_unused)
+    /* If pin 34 is explicitly configured, we do not mess with it. */
+    drv->amiga_pin34 = (pin34 == outp_unused);
+    if (!drv->amiga_pin34)
         return;
 
     IRQ_global_disable();
@@ -151,7 +160,8 @@ static void update_amiga_id(struct drive *drv, bool_t amiga_hd_id)
      * the HD-ID sequence 101010... with the host poll loop. It turns out that
      * starting with pin 34 asserted when the HD image is mounted seems to
      * generally work! */
-    drive_change_pin(&drive, pin_34, TRUE);
+    if (ff_cfg.motor_delay == MOTOR_ignore)
+        drive_change_pin(&drive, pin_34, TRUE);
 }
 
 void floppy_cancel(void)
@@ -613,6 +623,10 @@ static void motor_spinup_timer(void *_drv)
     struct drive *drv = _drv;
 
     drv->motor.on = TRUE;
+    if (drv->amiga_pin34) {
+        IRQ_global_disable();
+        drive_change_pin(drv, pin_34, TRUE);
+    }
     drive_change_output(drv, outp_rdy, TRUE);
 }
 

src/floppy_generic.c

@@ -51,6 +51,7 @@ static struct drive {
     bool_t writing;
     bool_t sel;
     bool_t index_suppressed; /* disable IDX while writing to USB stick */
+    bool_t amiga_pin34;
     uint8_t outp;
     volatile bool_t inserted;
     struct timer chgrst_timer;

src/gotek/board.c

@@ -144,6 +144,19 @@ void board_setup_rotary_exti(void)
     exti->imr |= m;
 }
 
+void board_jc_set_mode(unsigned int mode)
+{
+    if (mcu_package == MCU_QFN32) {
+#if !defined(NDEBUG)
+        /* PA9 is used for serial tx */
+#else
+        gpio_configure_pin(gpioa, 9, mode);
+#endif
+    } else {
+        gpio_configure_pin(gpiob, 1, mode);
+    }
+}
+
 bool_t board_jc_strapped(void)
 {
     if (mcu_package == MCU_QFN32) {

src/gotek/floppy.c

@@ -394,6 +394,12 @@ static void IRQ_WGATE_rotary(void)
 static void IRQ_MOTOR(struct drive *drv)
 {
     GPIO gpio = gotek_enhanced() ? gpioa : gpiob;
+    bool_t mtr_asserted = !(gpio->idr & m(pin_motor));
+
+    if (drv->amiga_pin34 && (ff_cfg.motor_delay != MOTOR_ignore)) {
+        IRQ_global_disable();
+        drive_change_pin(drv, pin_34, !mtr_asserted);
+    }
 
     timer_cancel(&drv->motor.timer);
     drv->motor.on = FALSE;
@@ -405,7 +411,7 @@ static void IRQ_MOTOR(struct drive *drv)
         /* Motor signal ignored -- MOTOR ON */
         drv->motor.on = TRUE;
         drive_change_output(drv, outp_rdy, TRUE);
-    } else if (gpio->idr & m(pin_motor)) {
+    } else if (!mtr_asserted) {
         /* Motor signal off -- MOTOR OFF */
         drive_change_output(drv, outp_rdy, FALSE);
     } else {