Update README.md

README.md

@@ -2,22 +2,33 @@
 
 TinyFrame is a simple library for building and parsing frames to be sent 
 over a serial interface (e.g. UART, telnet etc.). The code is written 
-in `--std=gnu89`.
+to build with `--std=gnu89` and later.
 
-Frames are protected by a checksum (~XOR, CRC16 or CRC32) and contain 
-a unique ID field, which can be used for chaining messages. The highest value 
-of the ID is different for each peer (TF_MASTER or TF_SLAVE) to avoid collisions.
+TinyFrame is suitable for a wide range of applications, including inter-microcontroller 
+communication, as a protocol for FTDI-based PC applications or for messaging through
+UDP packets. If you find a good use for it, please let me know so I can add it here!
 
-All fields in the frame have configurable size (see the top of the header file).
-By just changing a value, like `TF_LEN_BYTES`, the library seamlessly switches 
-from `uint8_t` to `uint16_t` or `uint32_t` to support longer payloads.
+Frames can be protected by a checksum (~XOR, CRC16 or CRC32) and contain 
+a unique ID field which is be used for chaining related messages. The highest bit 
+of the generated IDs is different for each peer to avoid collisions.
+Peers are functionally equivalent and can send messages to each other 
+(the names "master" and "slave" are used only for convenience).
 
-The library lets you bind listeners waiting for any frame, a particular frame Type,
-or a specific message ID. This lets you easily implement asynchronous
+The library lets you register listeners (callback functions) to wait for (1) any frame, (2)
+a particular frame Type, or (3) a specific message ID. This lets you easily implement asynchronous
 communication.
 
 ## Frame structure
 
+All fields in the message frame have a configurable size (see the top of the header file).
+By just changing a definition in the header, such as `TF_LEN_BYTES` (1, 2 or 4), the library
+seamlessly switches between `uint8_t`, `uint16_t` and `uint32_t`. Choose field lengths that
+best suit your application needs. 
+
+For example, you don't need 4 bytes (`uint32_t`) for the 
+length field if your payloads are 20 bytes long, using a 1-byte field (`uint8_t`) will save
+3 bytes. This may be significant if you high throughput.
+
 ```
 ,-----+----+-----+------+------------+- - - -+------------,                
 | SOF | ID | LEN | TYPE | HEAD_CKSUM | DATA  | PLD_CKSUM  |                
@@ -35,8 +46,9 @@ DATA_CKSUM .. checksum, implemented as XOR of all preceding bytes in the message
 
 ## Usage Hints
 
-- Both peers must include the library with the same parameters (config in the header file)
-- Start by calling `TF_Init()` with MASTER or SLAVE as the argument
+- All TinyFrame functions, typedefs and macros start with the `TF_` prefix.
+- Both peers must include the library with the same parameters (configured at the top of the header file)
+- Start by calling `TF_Init()` with `TF_MASTER` or `TF_SLAVE` as the argument
 - Implement `TF_WriteImpl()` - declared at the bottom of the header file as `extern`.
   This function is used by `TF_Send()` to write bytes to your UART (or other physical layer).
   Presently, always a full frame is sent to this function.