add a bit more info and dev status in readme.

Author: thomasfla

src/current/rp2350/README.md

@@ -4,12 +4,63 @@
 *warning* Work in progress
 
 Implementation of current sensing on RP2350 using the PIO to read SPI based ADCs.
+Wiring:
 
+* SCK_PIN -> Clock pin shared with 3 ADCs
+* CSB_PIN -> Chip Select pin shared with 3 ADCs
+* D0, D1 D2 -> The 3 data output from the ADCs. Needs to be contigus (D1=D0+1 D2=D1+1)
 
 Temporarly, for this to work, we need to add a PWM chanell in Arduino-FOC rp2040 hardware specific files. The duty cyctle needs to be computed to trigger the ADC at the right-time.
-The PWM pin is hardcoded to GPIO11 for now.
 
 
+TODO:
+* Init a the DMA or IRQ to read samples from PIO.
+* Activate the push of adc data in PIO program (disabled for tests)
+* Find a way to setup the trigger PWM from the driver, or change the arduino-foc lib.
+
+
+
+# Example:
+```
+// Open loop motor control example With current readings (work in progress)
+#include <SimpleFOC.h>
+#include "pico/stdlib.h"
+#include "hardware/pio.h"
+#include "hardware/clocks.h"
+#include <SimpleFOCDrivers.h>
+#include "current/rp2350/RP2350PIOCurrentSense.h"
+
+static const uint SCK_PIN   = 2;  // sideset pin
+static const uint CSB_PIN   = 3;  // set pin
+static const uint D0_PIN    = 4;  // D0..D2 must be contiguous (D1=D0+1, D2=D0+2)
+static const uint TRIG_PIN  = 8;  // This need to be also configure as an extra PWM output with custom fixed duty cycle. For now let's just one of the phase as the trigger.
+
+BLDCMotor motor = BLDCMotor(11);
+BLDCDriver3PWM driver = BLDCDriver3PWM(7, 8, 9);
+RP2350PIOCurrentSense curr = RP2350PIOCurrentSense(1.0, 4096,SCK_PIN, CSB_PIN, D0_PIN, TRIG_PIN);
+
+float target_velocity = 0.2;
+
+void setup() {
+  Serial.begin(115200);
+  SimpleFOCDebug::enable(&Serial);
+  driver.voltage_power_supply = 12;
+  driver.voltage_limit = 12;
+  driver.init();
+  motor.linkDriver(&driver);
+  motor.voltage_limit = 2;   // [V]
+  motor.controller = MotionControlType::velocity_openloop;
+  motor.init();
+  Serial.println("Motor ready!");
+  _delay(100);
+  curr.init();
+}
+
+void loop() {
+  motor.move(target_velocity);
+}
+```
+
 
 ## Compilling the PIO program
 To manually compile the PIO files (generating a .pio.h from a pio), you need to instal pioasm.