USB interface proof-of-concept implementation

fw/caster.c

@@ -92,3 +92,9 @@ uint8_t caster_setmode(uint16_t x0, uint16_t y0, uint16_t x1, uint16_t y1,
     fpga_write_reg8(CSR_OP_CMD, OP_EXT_SETMODE);
     return 0;
 }
+
+uint8_t caster_setinput(uint8_t input_src) {
+    if (is_busy()) return 1;
+    fpga_write_reg8(CSR_CFG_IN_SRC, input_src);
+    return 0;
+}

fw/caster.h

@@ -52,6 +52,7 @@
 #define CSR_CFG_FBYTES_B2   27
 #define CSR_CFG_FBYTES_B1   28
 #define CSR_CFG_FBYTES_B0   29
+#define CSR_CFG_IN_SRC      30
 #define CSR_STATUS          32
 // Alias for 16bit registers
 #define CSR_LUT_ADDR        CSR_LUT_ADDR_HI
@@ -94,3 +95,4 @@ uint8_t caster_load_waveform(uint8_t *waveform, uint8_t frames);
 uint8_t caster_redraw(uint16_t x0, uint16_t y0, uint16_t x1, uint16_t y1);
 uint8_t caster_setmode(uint16_t x0, uint16_t y0, uint16_t x1, uint16_t y1,
         UPDATE_MODE mode);
+uint8_t caster_setinput(uint8_t input_src);

fw/usbapp.c

@@ -71,8 +71,42 @@ void tud_hid_set_report_cb(uint8_t instance, uint8_t report_id, hid_report_type_
     (void) report_id;
     (void) report_type;
 
-    // echo back anything we received from host
+    // Process the request
-    tud_hid_report(0, buffer, bufsize);
+    uint16_t cmd = (buffer[1] << 8) | buffer[0];
+    uint16_t param = (buffer[3] << 8) | buffer[2];
+    uint16_t x0 = (buffer[5] << 8) | buffer[4];
+    uint16_t y0 = (buffer[7] << 8) | buffer[6];
+    uint16_t x1 = (buffer[9] << 8) | buffer[8];
+    uint16_t y1 = (buffer[11] << 8) | buffer[10];
+    uint16_t id = (buffer[13] << 8) | buffer[12];
+    uint16_t chksum = (buffer[15] << 8) | buffer[14];
+    uint8_t retval = 1;
+    switch (buffer[0]) {
+    case USBCMD_RESET:
+        // reset system
+        (*((volatile uint32_t*)(PPB_BASE + 0x0ED0C))) = 0x5FA0004; // Reset via NVIC
+        break;
+    case USBCMD_POWERDOWN:
+        // TODO
+        break;
+    case USBCMD_POWERUP:
+        // TODO
+        break;
+    case USBCMD_SETINPUT:
+        retval = caster_setinput((uint8_t)param);
+        break;
+    case USBCMD_REDRAW:
+        retval = caster_redraw(x0, y0, x1, y1);
+        break;
+    case USBCMD_SETMODE:
+        retval = caster_setmode(x0, y0, x1, y1, (UPDATE_MODE)param);
+        break;
+    }
+
+    uint8_t txbuf[1];
+    txbuf[0] = retval;
+
+    tud_hid_report(0, txbuf, 1);
 }
 
 void usbapp_task(void) {

util/usb_example.py

@@ -0,0 +1,26 @@
+# Install python3 HID package https://pypi.org/project/hid/
+import hid
+import struct
+
+vid = 0xcafe
+pid = 0x4004
+
+dev = hid.Device(vid, pid)
+
+if not dev:
+    print("Unable to open device")
+    exit()
+
+cmd = 0x00
+param = 0x00
+x0 = 0
+y0 = 0
+x1 = 1600 - 1
+y1 = 1200 - 1
+pid = 0
+chksum = 0
+
+str_out = struct.pack('>h>h>h>h>h>h>h>h', cmd, param, x0, y0, x1, y1, pid, chksum)
+dev.write(str_out)
+str_in = dev.read(1)
+print("Received from HID Device:", str_in, '\n')