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thomasflathomasfla
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Add a PIO program for ADC bu79100g, work in progress
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5 files changed

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‎src/current/rp2350/README.md‎

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Implementation of current sensing on RP2350 using the PIO to read SPI based ADCs.
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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.
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The PWM pin is hardcoded to GPIO11 for now.
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## Compilling the PIO program
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To manually compile the PIO files (generating a .pio.h from a pio), you need to instal pioasm.
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Note for self, on my setup:
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```
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export PIOASM="$HOME/.arduino15/packages/rp2040/tools/pqt-pioasm/4.1.0-1aec55e/pioasm"
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"$PIOASM" -v 1 bu79100g_parallel3.pio bu79100g_parallel3.pio.h
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```

‎src/current/rp2350/RP2350PIOCurrentSense.cpp‎

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#include "RP2350PIOCurrentSense.h"
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RP2350PIOCurrentSense::RP2350PIOCurrentSense(float gain, uint32_t max_adc_value, int pinA, int pinB, int pinC) : CurrentSense() {
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this->pinA = pinA;
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this->pinB = pinB;
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this->pinC = pinC;
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RP2350PIOCurrentSense::RP2350PIOCurrentSense(float gain, uint32_t max_adc_value, int pinSCK, int pinCSB, int pinD0) : CurrentSense() {
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this->pinSCK = pinSCK;
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this->pinCSB = pinCSB;
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this->pinD0 = pinD0;
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this->pinD1 = pinD0+1;
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this->pinD2 = pinD0+2;
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this->gain_a = gain;
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this->gain_b = gain;
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this->gain_c = gain;
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this->max_adc_value = max_adc_value;
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};
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// TODO check that pins are valid for PIO use (e.g. consecutive pins on same bank)
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// TODO check that driver is linked
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// TODO init PIO
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// Done init PIO
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// TODO init ADC via SPI
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// TODO init DMA to transfer ADC data to memory buffer
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// TODO init timer to trigger PIO conversions at required frequency (check driver settings)
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// TDB: do we need config input to know which timer slice and channel to use? or can we pick automatically?
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// TODO start everything up
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float sck_hz = 20e6;
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PIO pio = pio0;
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int sm = pio_claim_unused_sm(pio0, false);
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if (sm < 0) { pio = pio1; sm = pio_claim_unused_sm(pio1, true); }
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uint off = pio_add_program(pio, &bu79100g_parallel3_program);
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pio_sm_config c = bu79100g_parallel3_program_get_default_config(off);
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// Map pins to the SM
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sm_config_set_in_pins(&c, this->pinD0); // reads D0..D2
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sm_config_set_set_pins(&c, this->pinCSB, 1); // CSB (1 pin)
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sm_config_set_sideset_pins(&c, this->pinSCK); // SCK (sideset)
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// Put pins into PIO control
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pio_gpio_init(pio, this->pinSCK);
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pio_gpio_init(pio, this->pinCSB);
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pio_gpio_init(pio, this->pinD0);
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pio_gpio_init(pio, this->pinD1);
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pio_gpio_init(pio, this->pinD2);
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// Directions (from the SM’s point of view)
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pio_sm_set_consecutive_pindirs(pio, sm, this->pinSCK, 1, true); // SCK out
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pio_sm_set_consecutive_pindirs(pio, sm, this->pinCSB, 1, true); // CS out
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pio_sm_set_consecutive_pindirs(pio, sm, this->pinD0, 3, false); // D0..D2 in
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// Shift config: right, autopush every 24 bits (two pushes per conversion)
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sm_config_set_in_shift(&c, true, true, 24);
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// SCK ≈ clk_sys / (2 * clkdiv) because each SCK period = 2 instructions
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float div = (float)clock_get_hz(clk_sys) / (2.0f * sck_hz);
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sm_config_set_clkdiv(&c, div);
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// Init & start the SM
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pio_sm_init(pio, sm, off, &c);
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pio_sm_set_enabled(pio, sm, true);
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return 0;
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};
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‎src/current/rp2350/RP2350PIOCurrentSense.h‎

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#pragma once
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#include "common/base_classes/CurrentSense.h"
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#include "bu79100g_parallel3.pio.h"
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class RP2350PIOCurrentSense: public CurrentSense {
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public:
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RP2350PIOCurrentSense(float gain, uint32_t max_adc_value, int pinA, int pinB, int pinC = _NC);
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RP2350PIOCurrentSense(float gain, uint32_t max_adc_value, int pinSCK, int pinCSB, int pinD0);
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~RP2350PIOCurrentSense();
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int init() override;
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PhaseCurrent_s getPhaseCurrents() override;
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protected:
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uint32_t max_adc_value; //!< maximum ADC value (e.g. 4096 for 12 bit ADC)
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int pinCSB;
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int pinSCK;
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int pinD0;
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int pinD1;
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int pinD2;
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int gain_a;
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int gain_b;
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int gain_c;
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};

‎src/current/rp2350/bu79100g_parallel3.pio‎

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.program bu79100g_parallel3
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; BU79100G-LA parallel read of 3 ADCs with a trigger GPIO
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; sideset pin: SCK (1 pin), CPOL=1 idle HIGH
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; set pin: CSB (1 pin)
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; in_base: D0..D2 (3 contiguous input pins)
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.side_set 1 opt ; 1 sideset bit to drive SCK
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.wrap_target
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set pins, 1 side 1 ; CSB=1, SCK=1
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; -------- wait external falling edge on absolute GPIO ----------
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wait 1 gpio 11 ; TODO, we will need to have this pin setable from the C code. direcetly edit the program?
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wait 0 gpio 11
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set pins, 0 side 1 ; CS=0, SCK=1
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set x, 15 side 1 ; prepare loop cpt
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; -------- 16 dummy clocks (no sampling) -----------------------
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dummy_loop:
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nop side 0 ; SCK=0
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jmp x--, dummy_loop side 1 ; SCK=1
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set pins, 1 side 1 ; CSB=0, keep SCK=HIGH at CSB falling (datasheet rec.)
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set x, 15 side 1
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set pins, 0
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; -------- 16 real clocks, sample on SCK rising edge -----------
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read_loop:
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nop side 1 ;DEBUG so we don't have to wait for autopush.
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;in pins, 3 side 1 ; SCK=1, sample D2..D0 on rising edge
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jmp x--, read_loop side 0 ; SCK=0
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; -------- finish conversion -----------------------------------
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set pins, 1 side 1 ; CSB=1, SCK=1
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.wrap

‎src/current/rp2350/bu79100g_parallel3.pio.h‎

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// -------------------------------------------------- //
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// This file is autogenerated by pioasm; do not edit! //
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// -------------------------------------------------- //
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#pragma once
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#if !PICO_NO_HARDWARE
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#include "hardware/pio.h"
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#endif
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// ------------------ //
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// bu79100g_parallel3 //
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// ------------------ //
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#define bu79100g_parallel3_wrap_target 0
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#define bu79100g_parallel3_wrap 12
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#define bu79100g_parallel3_pio_version 1
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static const uint16_t bu79100g_parallel3_program_instructions[] = {
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// .wrap_target
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0xf801, // 0: set pins, 1 side 1
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0x208b, // 1: wait 1 gpio, 11
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0x200b, // 2: wait 0 gpio, 11
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0xf800, // 3: set pins, 0 side 1
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0xf82f, // 4: set x, 15 side 1
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0xb042, // 5: nop side 0
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0x1845, // 6: jmp x--, 5 side 1
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0xf801, // 7: set pins, 1 side 1
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0xf82f, // 8: set x, 15 side 1
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0xe000, // 9: set pins, 0
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0xb842, // 10: nop side 1
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0x104a, // 11: jmp x--, 10 side 0
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0xf801, // 12: set pins, 1 side 1
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// .wrap
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};
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#if !PICO_NO_HARDWARE
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static const struct pio_program bu79100g_parallel3_program = {
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.instructions = bu79100g_parallel3_program_instructions,
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.length = 13,
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.origin = -1,
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.pio_version = bu79100g_parallel3_pio_version,
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#if PICO_PIO_VERSION > 0
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.used_gpio_ranges = 0x1
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#endif
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};
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static inline pio_sm_config bu79100g_parallel3_program_get_default_config(uint offset) {
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pio_sm_config c = pio_get_default_sm_config();
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sm_config_set_wrap(&c, offset + bu79100g_parallel3_wrap_target, offset + bu79100g_parallel3_wrap);
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sm_config_set_sideset(&c, 2, true, false);
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return c;
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}
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#endif
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