duty cycle + better handling of pli everything

Cargo.lock

@@ -2262,7 +2262,7 @@ dependencies = [
 
 [[package]]
 name = "tesla-charge-controller"
-version = "0.1.9-prerelease"
+version = "0.1.9"
 dependencies = [
  "anyhow",
  "async-channel",

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "tesla-charge-controller"
-version = "0.1.9-prerelease"
+version = "0.1.9"
 edition = "2021"
 license = "MITNFA"
 description = "Controls Tesla charge rate based on solar charge data"

src/pl_interface.rs

@@ -1,11 +1,13 @@
 use std::time::Duration;
 
+use anyhow::Context;
 use metrics::{describe_gauge, gauge, Gauge};
 use serialport::SerialPort;
 
 pub struct Pli {
     port: Box<dyn SerialPort>,
     voltage_gauge: Gauge,
+    duty_cycle: Gauge,
 }
 
 impl Pli {
@@ -16,15 +18,23 @@ impl Pli {
 
         describe_gauge!("pl_battery_voltage", "Battery voltage");
         let voltage_gauge = gauge!("pl_battery_voltage");
+        describe_gauge!("pl_duty_cycle", "Duty cycle");
+        let duty_cycle = gauge!("pl_duty_cycle");
+
         Ok(Self {
             port,
             voltage_gauge,
+            duty_cycle,
         })
     }
 
     pub fn refresh(&mut self) {
-        let batv = (self.read_ram(50) as f64) * (4. / 10.);
+        if let Ok(batv) = self.read_ram(50) {
-        self.voltage_gauge.set(batv);
+            self.voltage_gauge.set(((batv * 4) as f64) / 10.);
+        }
+        if let Ok(duty_cycle) = self.read_ram(39) {
+            self.duty_cycle.set((duty_cycle as f64) / 255.);
+        }
     }
 
     fn send_command(&mut self, req: [u8; 4]) {
@@ -36,17 +46,17 @@ impl Pli {
     fn receive<const LENGTH: usize>(&mut self) -> [u8; LENGTH] {
         let mut buf = [0; LENGTH];
         match self.port.read_exact(&mut buf) {
-            Ok(_) => {
+            Ok(_) => {}
-                println!("got buf {buf:?}")
+            Err(e) => log::error!("PLI serial read error: {e:#?}"),
-            }
-            Err(e) => println!("read error: {e:#?}"),
         }
         buf
     }
 
-    fn read_ram(&mut self, address: u8) -> u8 {
+    fn read_ram(&mut self, address: u8) -> anyhow::Result<u8> {
         self.send_command(command(20, address, 0));
-        self.receive::<2>()[1]
+        let buf: [u8; 2] = self.receive();
+        if buf[0] == 200 { Some(buf[1]) } else { None }
+            .context(format!("Error from PLI: {}", buf[0]))
     }
 }