docs: document registers socketn

Signed-off-by: Lachezar Lechev <elpiel93@gmail.com>

src/register.rs

@@ -156,7 +156,10 @@ pub const SOCKET7_BUFFER_RX: u8 = 0b000_11111;
 pub mod socketn {
     use derive_try_from_primitive::TryFromPrimitive;
 
+    /// The Protocol mode
     pub const MODE: u16 = 0x00;
+
+    /// The protocol modes that can be used with the `w5500`
     #[repr(u8)]
     pub enum Protocol {
         Closed = 0b00,
@@ -164,33 +167,102 @@ pub mod socketn {
         Udp = 0b10,
         MacRaw = 0b100,
     }
+
+    /// Socket n Command Register
+    ///
+    /// `Sn_CR`
+    // pub const COMMAND: u16 = 0b0001;
     pub const COMMAND: u16 = 0x01;
+
+    /// Socket n Commands
+    ///
+    /// `Sn_CR` register
     #[repr(u8)]
     pub enum Command {
         Open = 0x01,
+        /// [Datasheet page 46](https://docs.wiznet.io/img/products/w5500/W5500_ds_v110e.pdf):
+        ///
+        /// > This is valid only in TCP mode (Sn_MR(P3:P0) = Sn_MR_TCP). In this
+        /// > mode, Socket n operates as a ‘TCP server’ and waits for connection-
+        /// > request (SYN packet) from any ‘TCP client
         Listen = 0x02,
         Connect = 0x04,
         Discon = 0x08,
         Close = 0x10,
         Send = 0x20,
+
+        /// [Datasheet page 48](https://docs.wiznet.io/img/products/w5500/W5500_ds_v110e.pdf):
+        ///
+        /// > RECV completes the processing of the received data in Socket n RX
+        /// > Buffer by using a RX read pointer register (Sn_RX_RD).
+        /// > For more details, refer to Socket n RX Received Size Register
+        /// > (Sn_RX_RSR), Socket n RX Write Pointer Register (Sn_RX_WR), and
+        /// > Socket n RX Read Pointer Register (Sn_RX_RD).
         Receive = 0x40,
     }
 
     pub const INTERRUPT: u16 = 0x02;
+    /// | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 |
+    /// | Reserved | Reserved | Reserved | SEND_OK | TIMEOUT | RECV | DISCON | CON |
+    ///
+    /// | Bit | Symbol | Description |
+    /// | 7~5 | Reserved | Reserved |
+    /// | 4 | SENDOK | Sn_IR(SENDOK) | Interrupt Mask |
+    /// | 3 | TIMEOUT | Sn_IR(TIMEOUT) | Interrupt Mask |
+    /// | 2 | RECV | Sn_IR(RECV) | Interrupt Mask |
+    /// | 1 | DISCON | Sn_IR(DISCON) | Interrupt Mask |
+    /// | 0 | CON | Sn_IR(CON) | Interrupt Mask |
     #[repr(u8)]
     pub enum Interrupt {
         All = 0b11111111u8,
-        SendOk = 0b010000u8,
+        SendOk = 0b10000u8,
-        Timeout = 0b01000u8,
+        Timeout = 0b1000u8,
-        Receive = 0b00100u8,
+
+        /// Receive data
+        ///
+        /// bit 2, symbol `RECV`, `Sn_IR(RECV) Interrupt Mask`
+        Receive = 0b100u8,
+
+        /// Disconnect
+        ///
+        /// bit 1, symbol `DISCON`, `Sn_IR(DISCON) Interrupt Mask`
+        Disconnect = 0b10u8,
+
+        /// Connect
+        ///
+        /// bit 0, symbol `CON`, `Sn_IR(CON) Interrupt Mask`
+        Connect = 0b1u8,
     }
 
     pub const STATUS: u16 = 0x03;
+
+    /// Socket status register
+    ///
+    /// `W5500 Datasheet Version 1.1.0` page 49:
+    ///
+    /// > Sn_SR (Socket n Status Register) [R] [0x0003] [0x00]
+    ///
+    /// - 0x18 SOCK_FIN_WAIT
+    /// - 0x1A SOCK_CLOSING
+    /// - 0X1B SOCK_TIME_WAIT
+    /// > These indicate Socket n is closing.
+    /// > These are shown in disconnect-process such as active-close
+    /// > and passive-close.
+    /// > When Disconnect-process is successfully completed, or
+    /// > when timeout occurs, these change to SOCK_CLOSED.
+    ///
     #[repr(u8)]
-    #[derive(TryFromPrimitive)]
+    #[derive(TryFromPrimitive, Debug, Copy, Clone, PartialEq, Eq)]
+    // #[cfg_attr(feature = "defmt", derive(defmt::Format))]
     pub enum Status {
         Closed = 0x00,
         Init = 0x13,
+
+        /// [Datasheet page 49](https://docs.wiznet.io/img/products/w5500/W5500_ds_v110e.pdf):
+        ///
+        /// > This indicates Socket n is operating as ‘TCP server’ mode and
+        /// > waiting for connection-request (SYN packet) from a peer
+        /// > (‘TCP client’).
         Listen = 0x14,
         Established = 0x17,
         CloseWait = 0x1c,
@@ -206,6 +278,19 @@ pub mod socketn {
         LastAck = 0x1d,
     }
 
+    #[cfg(feature = "defmt")]
+    impl defmt::Format for Status {
+        fn format(&self, fmt: defmt::Formatter) {
+            // Format as hexadecimal.
+            defmt::write!(
+                fmt,
+                "Status::{} ({=u8:#x})",
+                defmt::Debug2Format(self),
+                *self as u8
+            );
+        }
+    }
+
     pub const SOURCE_PORT: u16 = 0x04;
 
     pub const DESTINATION_IP: u16 = 0x0C;
@@ -214,17 +299,87 @@ pub mod socketn {
 
     pub const RXBUF_SIZE: u16 = 0x1E;
 
+    /// Socket n TX Buffer Size Register
+    ///
+    /// `Sn_TXBUF_SIZE`
+    ///
+    /// From datasheet:
+    ///
+    /// > .. can be configured with 1,2,4,8, and 16 Kbytes.
+    /// >
+    /// > Although Socket n TX Buffer Block size is initially configured to 2Kbytes, user can
+    /// > be re-configure its size using Sn_TXBUF_SIZE. The total sum of Sn_TXBUF_SIZE
+    /// > cannot be exceed 16Kbytes. When exceeded, the data transmission error is
+    /// > occurred.
     pub const TXBUF_SIZE: u16 = 0x1F;
 
+    /// TX Free Size Register
+    ///
+    /// `Sn_TX_FSR`
+    ///
+    /// Socket n TX Free Size
+    ///
+    /// offset (register)
+    /// 0x0020 (Sn_TX_FSR0)
+    /// 0x0021 (Sn_TX_FSR1)
     pub const TX_FREE_SIZE: u16 = 0x20;
 
+    /// Socket n TX Read Pointer
+    ///
+    /// offset (register)
+    /// 0x0022 (Sn_TX_RD0)
+    /// 0x0023 (Sn_TX_RD1)
     pub const TX_DATA_READ_POINTER: u16 = 0x22;
 
+    /// Socket n TX Write Pointer
+    ///
+    /// offset (register)
+    /// 0x0024 (Sn_TX_WR0)
+    /// 0x0025 (Sn_TX_WR1)
+    ///
+    /// [Datasheet page 54](https://docs.wiznet.io/img/products/w5500/W5500_ds_v110e.pdf):
+    ///
+    /// > Sn_TX_WR (Socket n TX Write Pointer Register) [R/W] [0x0024-0x0025] [0x0000]
+    /// >
+    /// > Sn_TX_WR is initialized by OPEN command. However, if Sn_MR(P[3:0]) is TCP
+    /// > mode(‘0001’), it is re-initialized while connecting with TCP.
+    /// > It should be read or to be updated like as follows.
+    /// > 1. Read the starting address for saving the transmitting data.
+    /// > 2. Save the transmitting data from the starting address of Socket n TX
+    /// > buffer.
+    /// > 3. After saving the transmitting data, update Sn_TX_WR to the
+    /// > increased value as many as transmitting data size. If the increment value
+    /// > exceeds the maximum value 0xFFFF(greater than 0x10000 and the carry
+    /// > bit occurs), then the carry bit is ignored and will automatically update
+    /// > with the lower 16bits value.
+    /// > 4. Transmit the saved data in Socket n TX Buffer by using SEND/SEND
+    /// command
     pub const TX_DATA_WRITE_POINTER: u16 = 0x24;
 
+    /// Socket n Received Size Register
+    ///
+    /// `Sn_RX_RSR`
     pub const RECEIVED_SIZE: u16 = 0x26;
 
     pub const RX_DATA_READ_POINTER: u16 = 0x28;
 
+    /// Socket n Interrupt Mask
+    ///
+    /// offset (register)
+    /// 0x002C (Sn_IMR)
     pub const INTERRUPT_MASK: u16 = 0x2C;
+
+    #[cfg(test)]
+    mod tests {
+        use core::convert::TryFrom;
+
+        use super::Status;
+
+        #[test]
+        fn test_status_from_byte() {
+            let udp = 0x22_u8;
+            let status = Status::try_from(udp).expect("Should parse to Status");
+            assert_eq!(status, Status::Udp);
+        }
+    }
 }

src/uninitialized_device.rs

@@ -58,7 +58,6 @@ impl<SpiBus: Bus> UninitializedDevice<SpiBus> {
         self.initialize_with_host(host, mode_options)
     }
 
-
     /// The gateway overrides the passed `ip` ([`Ip4Addr`]) to end with `.1`.
     ///
     /// E.g. `let ip = "192.168.0.201".parse::<Ip4Addr>()` will become a device with a gateway `192.168.0.1`.