WIP - 128x16 data east

src/dmd_interface.h

@@ -11,6 +11,7 @@
 #include "dmd_interface_alving.pio.h"
 #include "dmd_interface_capcom.pio.h"
 #include "dmd_interface_capcom_hd.pio.h"
+#include "dmd_interface_de_x16.pio.h"
 #include "dmd_interface_desega.pio.h"
 #include "dmd_interface_gottlieb.pio.h"
 #include "dmd_interface_sega_hd.pio.h"

src/dmd_interface_de_x16.pio

@@ -0,0 +1,74 @@
+.define DE 7
+.define RDATA 6
+.define RCLK 5
+.define COLLAT 4
+.define DOTCLK 3
+.define SDATA 2
+.define SDATAEX 1
+.define FRAME_START_IRQ 5
+
+.program dmd_reader_de_x16
+
+    set x, 27               ; for the first irq based on DE, we need a delay of ~19.5 µs
+    wait irq FRAME_START_IRQ
+
+.wrap_target
+
+
+msb_check:
+    nop[31]
+    nop[31]
+    jmp x-- msb_check[22]     ; loop for ~19.5 µs (first irq) / ~22.25 µs
+    jmp pin reload_y_msb_lsb      ; if DOTCLK is high, it means we will have LSB + MSB
+
+    ; Padding for no MSB row case
+    set x, 5                      ; load 6 b(0b101) for 3 bits of LSB + 3 bits of MSB
+    set y, 31                     ; add padding 32 times
+no_msb_loop:
+    ; For the no MSB case we create a "fake" MSB row with custom padding, which is always 0101 per pixel. 
+    ; Because it is MSB, it will later be processed and multiplioed by 2, always resulting in 1010 (0101 * 2)
+    ; This can then be summed up with the LSB row to create either an ON state (pixval 3) or off state (pixval 0)
+    in null 1                     ; padding 0
+    in x, 3                       ; padding 101
+    in null 1                     ; padding 0
+    in x, 3                       ; padding 101
+    jmp y-- no_msb_loop
+    jmp reload_x_msb_lsb
+
+reload_y_msb_lsb:
+    set y, 1
+reload_x_msb_lsb:
+    set x, 31
+dotloop:
+    ; Because of PIO limitations, we read px 1 as 000v and px 2 as 0v00 (px1 = 0001 / 0000 & px 2 = 0100 / 0000)
+    ; The first bit of px 2 therefore always has a padding 0, which is supplied by GPIO 1 because it's pulled low permanently.
+    ; in pins 3 = (px 1 -> v)0(v <- px 2). Here the zero in the middle is the padding bit (GPIO 1), and the 1s on either side are the actual pixel values
+    ; This lets us create a unique combination which can now be processed by a LUT to create the correct pixel values for all X16 games
+    wait 1 gpio DOTCLK               ; rising edge
+    in null 3                        ; 000 padding for 4bpp 
+    in pins 3                        ; read value of px 1(GPIO2), padding 0 (GPIO1) and px 2 (GPIO0) as they're sampled on the same DOTCLK edge
+    in null 2                        ; 00 padding for 4bpp
+    wait 0 gpio DOTCLK               ; falling edge
+    jmp x-- dotloop
+    jmp y-- reload_x_msb_lsb
+
+    set x, 31                        ; reload x to create 22.5 µs delay for lsb_msb_check
+    wait 1 gpio COLLAT               ; sync on COLLAT so our lsb_msb_check will work
+.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_de_x16
+.wrap_target
+
+; Data East 128x16 frame detection
+; When DE goes low, check for the next rising edge of DE. If RDATA is high at that point we have found the start.
+
+detect_loop:
+    wait 0 gpio DE
+    wait 1 gpio DE
+    jmp pin, frame_start             ; Check if RDATA is high, otherwise back to beginning
+    jmp detect_loop
+
+frame_start:
+    irq FRAME_START_IRQ
+.wrap

src/dmdreader.cpp

@@ -324,7 +324,12 @@ DmdType detect_dmd() {
            (de < 4000) && (rdata > 115) && (rdata < 130)) {
     return DMD_WPC;
 
-    // Data East: DOTCLK: 640000 | DE: 5000 | RDATA: 80
+    // Data East X16: DOTCLK: 121000 or 60544 | DE: 1955 | RDATA: 120
+  } else if ((dotclk > 55000) && (dotclk < 125000) && (de > 1900) &&
+             (de < 2000) && (rdata > 110) && (rdata < 120)) {
+    return DMD_DE_X16;
+
+    // Data East X32: DOTCLK: 640000 | DE: 5000 | RDATA: 80
   } else if ((dotclk > 630000) && (dotclk < 650000) && (de > 4930) &&
              (de < 5070) && (rdata > 75) && (rdata < 85)) {
     return DMD_DESEGA;
@@ -798,6 +803,31 @@ bool dmdreader_init(bool return_on_no_detection) {
       break;
     }
 
+    case DMD_DE_X16: {
+      uint input_pins[] = {DE, RDATA};
+      gpio_set_inover(DOTCLK, GPIO_OVERRIDE_INVERT); // Needs to be inverted
+      // because it triggers on the falling edge in the original signal
+      dmdreader_programs_init(&dmd_reader_de_x16_program,
+                              dmd_reader_de_x16_program_get_default_config,
+                              &dmd_framedetect_de_x16_program,
+                              dmd_framedetect_de_x16_program_get_default_config,
+                              input_pins, 2, RDATA);
+      gpio_set_inover(DOTCLK, GPIO_OVERRIDE_INVERT); // invert DOTCLK signal
+
+      source_width = 128;
+      source_height = 16;
+      source_bitsperpixel = 4;  // Data East and Sega are 2bpp
+      target_bitsperpixel = 2;
+      // in DE-Sega, there's only one plane,
+      // containg one LSB row followed by one MSB row and so on
+      source_planesperframe = 1;
+      source_planehistoryperframe = 0;
+      // in DE-Sega each line is sent twice
+      source_lineoversampling = LINEOVERSAMPLING_2X;
+      source_mergeplanes = MERGEPLANES_NONE;
+      break;
+    }
+
     case DMD_DESEGA: {
       uint input_pins[] = {DE};
       dmdreader_programs_init(&dmd_reader_desega_program,

src/dmdreader.h

@@ -22,6 +22,7 @@ enum DmdType : uint8_t {
   DMD_WHITESTAR,
   DMD_SPIKE1,
   DMD_SAM,
+  DMD_DE_X16,
   DMD_DESEGA,
   DMD_SEGA_HD,
   DMD_GOTTLIEB,