Created USB_Desc to alter USB Config Errors

This was one of many changes along the path of discovering that `wfi`
seems to just break USBD.

This change is probably not necessary, but it feels more elegant.

README.md

@@ -17,7 +17,7 @@ This code implements a [uf2](https://github.com/microsoft/uf2) bootloader for RI
 - Runs off of internal 8 MHz oscillator (despite stability concerns)
     - The HSI oscillator's tolerance (-1.0% to +1.6%) is well outside of the range specified for USB full speed ($\pm$ 0.25%), but it seems to work in practice n=1 ¯\\\_(ツ)\_/¯
     - The vendor's ISP ROM bootloader also does this
-- Should work across most of the CH32V2xx and CH32V3xx family with appropriate changes to hardcoded constants.
+- Should work across CH32V2xx family with appropriate changes to hardcoded constants. Does *not* support CH32V3xx (which doesn't have USBD).
 - Allows both download to flash and to SRAM with the "not main flash" flag (this is how the RP2040 bootrom works)
     - Flash download address must be 08xxxxxx (i.e. not starting at 0)
     - SRAM download address must be 20xxxxxx

bootloader.c

@@ -468,10 +468,10 @@ __attribute__((naked)) int main(void) {
     R16_USBD_CNTR = 1;
     USB_DESCS[0].addr_tx = 0x30 / 2;
     USB_DESCS[0].addr_rx = 0x20 / 2;
-    USB_DESCS[0].count_rx = (8 << 10);
+    USB_DESCS[0].count_rx = ((8 / 2) << 10);
     USB_DESCS[1].addr_tx = 0xc0 / 2;
     USB_DESCS[1].addr_rx = 0x40 / 2;
-    USB_DESCS[1].count_rx = (2 << 10) | (1 << 15);
+    USB_DESCS[1].count_rx = (1 << 10) | (1 << 15);
     // XXX because the table is at offset 0 don't bother writing this
 
     // Attach USB
@@ -995,8 +995,10 @@ __attribute__((naked)) int main(void) {
                         while (!(STK_SR & 1)) {}
                         STK_CTLR = 0;
                         STK_SR = 0;
-                        R16_USBD_CNTR = 0b11;
                         R32_EXTEN_CTR &= ~(1 << 1);
+                        R16_USBD_CNTR = 1;
+                        R16_USBD_ISTR = 0;
+                        R16_USBD_CNTR = 0b11;
                         if (ADDRESS_HI >> 8 == 0x20) {
                             // ram boot, go back to original clock settings
                             R32_RCC_CFGR0 = (R32_RCC_CFGR0 & ~0b11) | 0b00;

usbDesc.h

@@ -0,0 +1,130 @@
+enum USB_bDescriptorType {
+    DESCRIPTOR_DEVICE = 0x1,
+    DESCRIPTOR_CONFIGURATION = 0x2,
+    DESCRIPTOR_CONFIGURATION = 0x4,
+    DESCRIPTOR_ENDPOINT = 0x5
+};
+
+enum USB_Type_BCD {
+    USB20 = 0x0200,
+    USB11 = 0x0110,
+    USB10 = 0x0100
+};
+
+
+
+enum USB_PID {
+    // Token Packets
+    OUT_TOKEN   = 0b0001,
+    IN_TOKEN    = 0b1001,
+    SOF_TOKEN   = 0b0101,
+    SETUP_TOKEN = 0b1101,
+
+    // Data Packets
+    DATA0_DATA  = 0b0011,
+    DATA1_DATA  = 0b1011,
+    DATA2_DATA  = 0b0111,
+    MDATA_DATA  = 0b1111,
+
+    // Handshake Packets
+    ACK_HANDSHAKE   = 0b0010,
+    NAK_HANDSHAKE   = 0b1010,
+    STALL_HANDSHAKE = 0b1110,
+    NYET_HANDSHAKE  = 0b0110,
+
+    // Special & Other Packets
+    PRE_SPECIAL   = 0b1100, // PREamble shares value with ERR
+    ERR_SPECIAL   = 0b1100, 
+    SPLIT_SPECIAL = 0b1000,
+    PING_SPECIAL  = 0b0100
+};
+
+
+enum Configuration_bmAttributes{
+    USB_BUS_POWERED = (1 << 7),
+    SELF_POWERED = (1 << 6),
+    REMOTE_WAKEUP = (1 << 5),
+};
+
+
+enum Endpoint_bmAttributes {
+    // Bits 1..0: Transfer Type
+    TRANSFER_TYPE_MASK        = 0b00000011,
+    TRANSFER_CONTROL          = 0b00000000,
+    TRANSFER_ISOCHRONOUS      = 0b00000001,
+    TRANSFER_BULK             = 0b00000010,
+    TRANSFER_INTERRUPT        = 0b00000011,
+
+    // Bits 3..2: Synchronization Type (Isochronous Mode only)
+    SYNC_TYPE_MASK            = 0b00001100,
+    SYNC_NOSYNC               = (0b00 << 2), // No Synchronization
+    SYNC_ASYNC                = (0b01 << 2), // Asynchronous
+    SYNC_ADAPTIVE             = (0b10 << 2), // Adaptive
+    SYNC_SYNCHRONOUS          = (0b11 << 2), // Synchronous
+
+    // Bits 5..4: Usage Type (Isochronous Mode only)
+    USAGE_TYPE_MASK           = 0b00110000,
+    USAGE_DATA                = (0b00 << 4), // Data Endpoint
+    USAGE_FEEDBACK            = (0b01 << 4), // Feedback Endpoint
+    USAGE_EXPLICIT_FEEDBACK   = (0b10 << 4), // Explicit Feedback Data Endpoint
+    USAGE_RESERVED            = (0b11 << 4)  // Reserved
+};
+
+enum Setup_bmRequestType {
+    // Bit 7: Data Phase Transfer Direction
+    DIR_MASK         = (1 << 7),
+    HOST_TO_DEVICE   = (0 << 7),
+    DEVICE_TO_HOST   = (1 << 7),
+
+    // Bits 6..5: Type
+    TYPE_MASK        = (0b11 << 5),
+    TYPE_STANDARD    = (0b00 << 5),
+    TYPE_CLASS       = (0b01 << 5),
+    TYPE_VENDOR      = (0b10 << 5),
+    TYPE_RESERVED    = (0b11 << 5),
+
+    // Bits 4..0: Recipient
+    RECIPIENT_MASK   = 0b11111,
+    RECIPIENT_DEVICE    = 0,
+    RECIPIENT_INTERFACE = 1,
+    RECIPIENT_ENDPOINT  = 2,
+    RECIPIENT_OTHER      = 3
+};
+
+
+enum Standard__Device_Requests {
+    GET_STATUS = 0x00,
+    /**
+     * GET_STATUS will reuturn a 16bit word. 
+     * D0 is "Self Powered" bit, if D0 == 0, then the device is powered by the bus
+     * D1 is the "Remote Wakeup" bit, if D1 == 1, then the host can wake up this device from suspend
+     */
+
+    CLEAR_FEATURE = 0x01,
+    SET_FEATURE = 0x03,
+    SET_ADDRESS = 0x05,
+    GET_DESCRIPTOR = 0x06,
+    SET_DESCRIPTOR = 0x07,
+    GET_CONFIGURATION = 0x08,
+    SET_CONFIGURATION = 0x09
+};
+
+enum Standard_Interface_Requests {
+    GET_STATUS = 0x00,
+    CLEAR_FEATURE = 0x01,
+    SET_FEATURE = 0x03,
+    GET_INTERFACE = 0x0A,
+    SET_INTERFACE = 0x11,
+};
+
+enum Standard_Endpoint_Requests {
+    GET_STATUS = 0x00,
+    CLEAR_FEATURE = 0x01,
+    SET_FEATURE = 0x03,
+    /**
+     * Clear Feature and Set Feature are used to set Endpoint Features. 
+     * The standard currently defines one endpoint feature selector, 
+     * ENDPOINT_HALT (0x00) which allows the host to stall and clear an endpoint.
+     */
+    SYNCH_FRAME  = 0x12,
+};