AP_Scripting: add example logging serial to dataflash

libraries/AP_Scripting/examples/UART_log.lua

@@ -0,0 +1,114 @@
+-- Reads data in from UART and logs to dataflash
+
+-- find the serial first (0) scripting serial port instance
+local port = serial:find_serial(0)
+
+if not port or baud == 0 then
+    gcs:send_text(0, "No Scripting Serial Port")
+    return
+end
+
+-- begin the serial port
+port:begin(9600)
+port:set_flow_control(0)
+
+-- table for strings used in decoding
+local log_data = {}
+local term_number = 1
+local valid = true
+local term
+
+-- number of terms we expect in the message
+local num_terms = 3
+-- maximum length of terms each term we expect
+local max_length = 20
+
+-- decode a basic string
+local function decode(byte)
+    local char = string.char(byte)
+    if char == '\r' or char == '\n' or char == ',' then
+
+        -- decode the term, note this assumes it is a number
+        log_data[term_number] = tonumber(term)
+        if not log_data[term_number] then
+            -- could not convert to a number, discard this message
+            valid = false
+        end
+        term = nil
+
+        -- not got to the end yet
+        if char == ',' then
+            -- move onto next term
+            if term_number < num_terms then
+                term_number = term_number + 1
+            end
+            return false
+        end
+
+        -- make sure we have the correct number of terms
+        if #log_data ~= num_terms then
+            valid = false
+        end
+
+        if not valid then
+            log_data = {}
+        end
+
+        -- reset for the next message
+        local is_valid = valid
+        term_number = 1
+        valid = true
+
+        return is_valid
+    end
+
+    -- ordinary characters are added to term
+    -- if we have too many terms or they are too long then don't add to them
+    if term_number <= num_terms then
+        if term then
+            if string.len(term) < max_length then
+                term = term .. char
+            else
+                valid = false
+            end
+        else
+            term = char
+        end
+    else
+        valid = false
+    end
+
+    return false
+end
+
+-- the main update function that is used to read in data from serial port
+function update()
+
+    if not port then
+        gcs:send_text(0, "no Scripting Serial Port")
+        return update, 100
+    end
+
+    local n_bytes = port:available()
+    while n_bytes > 0 do
+        local byte = port:read()
+        if decode(byte) then
+            -- we have got a full line
+            -- save to data flash
+
+            -- care must be taken when selecting a name, must be less than four characters and not clash with an existing log type
+            -- format characters specify the type of variable to be logged, see AP_Logger/README.md
+            -- not all format types are supported by scripting only: i, L, e, f, n, M, B, I, E, and N
+            -- Note that Lua automatically adds a timestamp in micro seconds
+            logger.write('SCR','Sensor1, Sensor2, Sensor3','fff',table.unpack(log_data))
+
+            -- reset for the next message
+            log_data = {}
+        end
+        n_bytes = n_bytes - 1
+    end
+
+    return update, 100
+end
+
+return update, 100