Capcom support

src/dmd_interface.h

@@ -11,6 +11,7 @@
 #include "dmd_interface_desega.pio.h"
 #include "dmd_interface_whitestar.pio.h"
 #include "dmd_interface_wpc.pio.h"
+#include "dmd_interface_capcom.pio.h"
 #include "dmdreader_pins.h"
 #include "hardware/gpio.h"
 #include "hardware/pio.h"

src/dmd_interface_capcom.pio

@@ -0,0 +1,47 @@
+.define DE 7
+.define RDATA 6
+.define RCLK 5
+.define COLLAT 4
+.define DOTCLK 3
+.define SDATA 2
+.define PLANE_START_IRQ 4
+
+.program dmd_reader_capcom
+    set x, 31          ; load 31, 5 bits is max allowed (0b11111)
+    in x, 5            ; shift in 5 bits, isr is 31 now
+    set x, 3           ; load 3
+    in x, 2            ; shift in 2 bits, isr is 127 now
+    mov osr, isr       ; copy 127 to OSR
+    mov isr, null      ; reset shift counter
+
+.wrap_target
+    set y, 31          ; number of rows
+
+    irq clear PLANE_START_IRQ
+    wait irq PLANE_START_IRQ
+
+row_loop:
+    mov x, osr         ; load number of dots to skip (128)
+dot_skip_loop:
+    wait 0 gpio DOTCLK ; no DOTCLK period or faling edge of the previous
+    wait 1 gpio DOTCLK
+    jmp x-- dot_skip_loop       ; skip 128 dots
+
+    mov x, osr         ; load number of pixels to read (128)
+dot_read_loop:
+    wait 0 gpio DOTCLK ; no DOTCLK period or faling edge of the previous
+    in null 1          ; left padding a 0 to the output as WPC is 2bit/px
+    wait 1 gpio DOTCLK ; raising edge
+    in pins 1          ; read 1 bit pin data
+    jmp x-- dot_read_loop
+    jmp y-- row_loop
+.wrap
+
+; Frame detection program runs in parallel to the reader program and signals the start of a new frame using an IRQ.
+.program dmd_framedetect_capcom
+.wrap_target
+    wait 1 gpio RDATA
+    wait 0 gpio RCLK
+    irq PLANE_START_IRQ
+    wait 0 gpio RDATA
+.wrap

src/dmdreader.cpp

@@ -70,6 +70,7 @@ typedef struct __attribute__((__packed__)) block_pix_crc_header_t {
 #define DMD_SPIKE1 3
 #define DMD_SAM 4
 #define DMD_DESEGA 5
+#define DMD_CAPCOM 6
 
 // Line oversampling
 #define LINEOVERSAMPLING_NONE 1
@@ -327,6 +328,11 @@ int detect_dmd() {
   } else if ((dotclk > 645000) && (dotclk < 669000) && (de > 5075) &&
              (de < 5200) && (rdata > 75) && (rdata < 85)) {
     return DMD_WHITESTAR;
+
+    // Capcom -> DOTCLK: 4168000 | DE: 16280 | RDATA: 510
+  } else if ((dotclk > 4000000) && (dotclk < 4300000) && (de > 16000) &&
+             (de < 16500) && (rdata > 490) && (rdata < 530)) {
+    return DMD_CAPCOM;
   }
 #endif
 
@@ -649,6 +655,36 @@ void dmdreader_init() {
       source_mergeplanes = MERGEPLANES_NONE;
       break;
     }
+
+    case DMD_CAPCOM: {
+      dmd_pio = pio0;
+      offset = pio_add_program(dmd_pio, &dmd_reader_capcom_program);
+      dmd_sm = pio_claim_unused_sm(dmd_pio, true);
+      pio_sm_config dmd_config =
+          dmd_reader_capcom_program_get_default_config(offset);
+      dmd_reader_program_init(dmd_pio, dmd_sm, offset, dmd_config);
+
+      // The framedetect program just runs and detects the beginning of a new
+      // frame
+      uint input_pins[] = {RDATA, RCLK};
+      frame_pio = pio0;
+      offset = pio_add_program(frame_pio, &dmd_framedetect_capcom_program);
+      frame_sm = pio_claim_unused_sm(frame_pio, true);
+      pio_sm_config frame_config =
+          dmd_framedetect_capcom_program_get_default_config(offset);
+      dmd_framedetect_program_init(frame_pio, frame_sm, offset, frame_config,
+                                   input_pins, 2, 0);
+      pio_sm_set_enabled(frame_pio, frame_sm, true);
+
+      source_width = 128;
+      source_height = 32;
+      source_bitsperpixel = 2; 
+      source_pixelsperbyte = 8 / source_bitsperpixel;
+      source_planesperframe = 4;
+      source_lineoversampling = LINEOVERSAMPLING_NONE;
+      source_mergeplanes = MERGEPLANES_ADD;
+      break;
+    }
   }
 
   // Calculate display parameters