From c3d96b4494285848b70ede89fc35a1098adde60b Mon Sep 17 00:00:00 2001
From: Andrew Tridgell <andrew@tridgell.net>
Date: Mon, 14 Aug 2023 11:01:16 +1000
Subject: [PATCH] AP_Scripting: added EFI driver for DLA EFI serial protocol

a simple serial protocol, no CRC, gap framed
---
 libraries/AP_Scripting/drivers/EFI_DLA.lua | 188 +++++++++++++++++++++
 libraries/AP_Scripting/drivers/EFI_DLA.md  |  50 ++++++
 2 files changed, 238 insertions(+)
 create mode 100644 libraries/AP_Scripting/drivers/EFI_DLA.lua
 create mode 100644 libraries/AP_Scripting/drivers/EFI_DLA.md

diff --git a/libraries/AP_Scripting/drivers/EFI_DLA.lua b/libraries/AP_Scripting/drivers/EFI_DLA.lua
new file mode 100644
index 0000000000000..9c764ac4a38b2
--- /dev/null
+++ b/libraries/AP_Scripting/drivers/EFI_DLA.lua
@@ -0,0 +1,188 @@
+--[[
+ DLA serial EFI protocol
+
+ Note that this protocol is gap framed, no CRC
+
+ https://www.austars-model.com/dla-232cc-uavuas-engine-optional-one-key-startauto-startergenerator_g17937.html
+--]]
+
+local PARAM_TABLE_KEY = 41
+local PARAM_TABLE_PREFIX = "EFI_DLA_"
+
+local MAV_SEVERITY = {EMERGENCY=0, ALERT=1, CRITICAL=2, ERROR=3, WARNING=4, NOTICE=5, INFO=6, DEBUG=7}
+
+-- bind a parameter to a variable given
+local function bind_param(name)
+    local p = Parameter()
+    assert(p:init(name), string.format('could not find %s parameter', name))
+    return p
+end
+
+-- add a parameter and bind it to a variable
+local function bind_add_param(name, idx, default_value)
+    assert(param:add_param(PARAM_TABLE_KEY, idx, name, default_value), string.format('could not add param %s', name))
+    return bind_param(PARAM_TABLE_PREFIX .. name)
+end
+
+-- setup script specific parameters
+assert(param:add_table(PARAM_TABLE_KEY, PARAM_TABLE_PREFIX, 8), 'could not add param table')
+
+--[[
+  // @Param: EFI_DLA_ENABLE
+  // @DisplayName: EFI DLA enable
+  // @Description: Enable EFI DLA driver
+  // @Values: 0:Disabled,1:Enabled
+  // @User: Standard
+--]]
+EFI_DLA_ENABLE = bind_add_param("ENABLE", 1, 0)
+
+--[[
+  // @Param: EFI_DLA_LPS
+  // @DisplayName: EFI DLA fuel scale
+  // @Description: EFI DLA litres of fuel per second of injection time
+  // @Range: 0.00001 1
+  // @Units: litres
+  // @User: Standard
+--]]
+EFI_DLA_LPS = bind_add_param("LPS", 2, 0.001)
+
+if EFI_DLA_ENABLE:get() ~= 1 then
+   return
+end
+
+local uart = serial:find_serial(0) -- first scripting serial
+if not uart then
+   gcs:send_text(MAV_SEVERITY.ERROR, "EFI_DLA: unable to find scripting serial")
+   return
+end
+uart:begin(115200)
+
+local efi_backend = efi:get_backend(0)
+if not efi_backend then
+   gcs:send_text(MAV_SEVERITY.ERROR, "EFI_DLA: unable to find EFI backend")
+   return
+end
+
+--[[
+   discard n bytes
+--]]
+local function discard_bytes(n)
+   for _ = 1, n do
+      uart:read()
+   end
+end
+
+local function read_bytes(n)
+   local ret = ""
+   for _ = 1, n do
+      ret = ret .. string.char(uart:read())
+   end
+   return ret
+end
+
+local state = {}
+state.last_read_us = uint32_t(0)
+state.total_fuel_cm3 = 0.0
+
+--[[
+   check for input and parse data
+--]]
+local function check_input()
+   local n_bytes = uart:available():toint()
+   --gcs:send_text(MAV_SEVERITY.INFO, string.format("n_bytes=%u %.2f", n_bytes, millis():tofloat()*0.001))
+   if n_bytes < 82 then
+      return
+   end
+   if n_bytes > 82 then
+      discard_bytes(n_bytes)
+      return
+   end
+
+   state.seconds, state.pw1, state.pw2 = string.unpack("<HHH", read_bytes(6))
+   state.rpm, state.adv_deg, state.squirt = string.unpack("<HhB", read_bytes(5))
+   state.engine, state.afrtgt1, state.afrtgt2 = string.unpack("<BBB", read_bytes(3))
+   state.wbo2_en1, state.wbo2_en2, state.baro = string.unpack("<BBh", read_bytes(4))
+   state.map, state.mat, state.clt = string.unpack("<hhh", read_bytes(6))
+   state.tps, state.batt = string.unpack("<hh", read_bytes(4))
+
+   state.last_read_us = micros()
+
+   -- discard the rest
+   discard_bytes(uart:available():toint())
+end
+
+--[[
+   request more data
+--]]
+local function request_data()
+   --uart:write(string.byte("a"))
+   uart:write(0x61)
+end
+
+local function farenheight_to_C(v)
+   return (v + 459.67) * 0.55556
+end
+
+--[[
+   update EFI state
+--]]
+local function update_EFI()
+   if state.last_read_us == uint32_t(0) then
+      return
+   end
+   local cylinder_state = Cylinder_Status()
+   local efi_state = EFI_State()
+
+   -- 4.3.x incorrectly uses C instead of kelvin
+   -- local C_TO_KELVIN = 273.2
+
+   cylinder_state:cylinder_head_temperature(farenheight_to_C(state.clt*0.1))
+   cylinder_state:exhaust_gas_temperature(farenheight_to_C(state.mat*0.1))
+   cylinder_state:ignition_timing_deg(state.adv_deg*0.1)
+
+   local inj_time_ms = (state.pw1+state.pw2)*0.001
+   cylinder_state:injection_time_ms(inj_time_ms)
+
+   efi_state:engine_speed_rpm(state.rpm)
+
+   efi_state:atmospheric_pressure_kpa(state.baro*0.1)
+   efi_state:intake_manifold_pressure_kpa(state.map*0.1)
+   efi_state:intake_manifold_temperature(farenheight_to_C(state.mat*0.1))
+   efi_state:throttle_position_percent(math.floor(state.tps*0.1))
+   efi_state:ignition_voltage(state.batt*0.1)
+
+   local now_us = micros()
+   local dt = (now_us - state.last_read_us):tofloat()*1.0e-6
+   state.last_read_us = now_us
+
+   local revs = state.rpm * 60.0 * dt
+   local inj_time = revs * inj_time_ms * 0.001
+   local fuel_used_cm3 = EFI_DLA_LPS:get() * 0.001 * inj_time
+
+   state.total_fuel_cm3 = state.total_fuel_cm3 + fuel_used_cm3
+
+   efi_state:fuel_consumption_rate_cm3pm((fuel_used_cm3 / dt) * 60.0)
+   efi_state:estimated_consumed_fuel_volume_cm3(state.total_fuel_cm3)
+   
+   efi_state:cylinder_status(cylinder_state)
+   efi_state:last_updated_ms(millis())
+
+   -- Set the EFI_State into the EFI scripting driver
+   efi_backend:handle_scripting(efi_state)
+end
+
+
+--[[
+   main update function
+--]]
+local function update()
+   check_input()
+   update_EFI()
+   request_data()
+
+   return update, 100
+end
+
+gcs:send_text(MAV_SEVERITY.INFO, "EFI_DLA: loaded")
+
+return update()
diff --git a/libraries/AP_Scripting/drivers/EFI_DLA.md b/libraries/AP_Scripting/drivers/EFI_DLA.md
new file mode 100644
index 0000000000000..5996a9758a3e0
--- /dev/null
+++ b/libraries/AP_Scripting/drivers/EFI_DLA.md
@@ -0,0 +1,50 @@
+# EFI DLA Driver
+
+This driver implements support for the DLA EFI serial protocol for
+this system:
+
+https://www.austars-model.com/dla-232cc-uavuas-engine-optional-one-key-startauto-startergenerator_g17937.html
+
+# Parameters
+
+The script used the following parameters:
+
+## EFI_DFA_ENABLE
+
+this must be set to 1 to enable the driver
+
+## EFI_DFA_LPS
+
+This sets the fuel consumption rate in litres per second of injector
+time. This will need to be tuned per engine to give the right value
+for fuel usage and total fuel
+
+# Operation
+
+This driver should be loaded by placing the lua script in the
+APM/SCRIPTS directory on the microSD card, which can be done either
+directly or via MAVFTP. The following key parameters should be set:
+
+ - SCR_ENABLE should be set to 1
+ - EFI_TYPE should be set to 7
+ - EFI_DFA_ENABLE should be set to 1
+ - SERIALn_PROTOCOL should be set to 28 for the connected EFI serial
+ - RPM_TYPE1 should be set to 3
+ - ICE_ENABLE should be set to 1
+
+then the flight controller should rebooted and parameters should be
+refreshed.
+
+Once loaded the EFI_DLA parameters will appear and should be set
+according to the parameter list above.
+
+The GCS will receive EFI_STATUS MAVLink messages which includes RPM,
+cylinder head temperature, injection timing, engine load, fuel
+consumption rate, throttle position atmospheric pressure and ECU
+voltage.
+
+Note that this EFI system only sends data when the enable PWM enable
+signal is high. If that is hooked to the ignition control in ArduPilot
+ICE system then you won't see any data until you start the engine.
+
+