eps.c

Go to the documentation of this file.

#include "board.h"
#include "../uart.h"
#include "../rtc.h"
#include "../eps.h"

#define EPS_BAUDRATE    57600

#define EPS_REG_CONFIG      0x00
#define EPS_REG_STATUS      0x01
#define EPS_REG_SW_ON       0x02
#define EPS_REG_POWER       0x03
#define EPS_REG_BAT_V       0x04
#define EPS_REG_BAT_I       0x05
#define EPS_REG_BAT_T       0x06
#define EPS_REG_SOLAR_N1_I  0x07
#define EPS_REG_SOLAR_N2_I  0x08
#define EPS_REG_SOLAR_S1_I  0x09
#define EPS_REG_SOLAR_S2_I  0x0A
#define EPS_REG_SOLAR_E1_I  0x0B
#define EPS_REG_SOLAR_E2_I  0x0C
#define EPS_REG_SOLAR_W1_I  0x0D
#define EPS_REG_SOLAR_W2_I  0x0E
#define EPS_REG_SOLAR_T1_I  0x0F
#define EPS_REG_SOLAR_T2_I  0x10
#define EPS_REG_RESERVED    0x11 // Maybe make known ID? ( https://github.com/uos3/eps-firmware/issues/1 )
#define EPS_REG_SOLAR_2_V   0x12
#define EPS_REG_RAIL1_BOOT  0x13
#define EPS_REG_RAIL1_FAIL  0x14
#define EPS_REG_RAIL1_V     0x15
#define EPS_REG_RAIL1_I     0x16
#define EPS_REG_RAIL2_BOOT  0x17
#define EPS_REG_RAIL2_FAIL  0x18
#define EPS_REG_RAIL2_V     0x19
#define EPS_REG_RAIL2_I     0x1A
#define EPS_REG_RAIL3_BOOT  0x1B
#define EPS_REG_RAIL3_FAIL  0x1C
#define EPS_REG_RAIL3_V     0x1D
#define EPS_REG_RAIL3_I     0x1E
#define EPS_REG_RAIL4_BOOT  0x1F
#define EPS_REG_RAIL4_FAIL  0x20
#define EPS_REG_RAIL4_V     0x21
#define EPS_REG_RAIL4_I     0x22
#define EPS_REG_RAIL5_BOOT  0x23
#define EPS_REG_RAIL5_FAIL  0x24
#define EPS_REG_RAIL5_V     0x25
#define EPS_REG_RAIL5_I     0x26
#define EPS_REG_RAIL6_BOOT  0x27
#define EPS_REG_RAIL6_FAIL  0x28
#define EPS_REG_RAIL6_V     0x29
#define EPS_REG_RAIL6_I     0x2A
#define EPS_REG_SUPPLY_3_V  0x2B
#define EPS_REG_SUPPLY_3_I  0x2C
#define EPS_REG_SUPPLY_5_V  0x2D
#define EPS_REG_SUPPLY_5_I  0x2E
#define EPS_REG_CHARGE_I    0x2F
#define EPS_REG_MPPT_BUS_V  0x30
#define EPS_REG_CRC_ER_CNT  0x31
#define EPS_REG_DROP_CNT    0x32

typedef struct eps_master_packet_t {
  bool write:1;
  uint8_t register_id:7;
  uint8_t value_l;
  uint8_t value_h;
  uint8_t crc_l;
  uint8_t crc_h;
} eps_master_packet_t;

typedef struct eps_slave_packet_single_t {
  bool    reserved_a:1;
  uint8_t register_id:7;
  bool    reserved_b:1;
  uint8_t register_quantity:7;
  uint16_t value;
  uint16_t crc;
} eps_slave_packet_single_t;

static eps_master_packet_t eps_master_packet;
static eps_slave_packet_single_t eps_slave_packet_single;


static bool EPS_readRegister(uint8_t register_id, eps_slave_packet_single_t *data);
static uint16_t EPS_crc(uint8_t *message, int32_t offset, int32_t length);


void EPS_init(void)
{
  UART_init(UART_EPS, EPS_BAUDRATE);
}

bool EPS_selfTest(void)
{
  /* Ref: https://github.com/uos3/eps-firmware/issues/1 */
  //EPS_readRegister(EPS_REG_RESERVED, &eps_slave_packet_single);
  //return (eps_slave_packet_single.value == EPS_ID);

  return true;
}

bool EPS_getBatteryVoltage(uint16_t *voltage)
{
  if(EPS_readRegister(EPS_REG_BAT_V, &eps_slave_packet_single))
  {
    *voltage = eps_slave_packet_single.value;
    return true;
  }
  return false;
}

static bool EPS_readRegister(uint8_t register_id, eps_slave_packet_single_t *data)
{
  char c;
  uint16_t crc, bytes_expected, bytes_received;
  uint32_t timeout, current_time;

  /* Construct Master Read Packet */
  eps_master_packet.write = false;
  eps_master_packet.register_id = (uint8_t)(register_id & 0x7F);
  eps_master_packet.value_l = 1;
  eps_master_packet.value_h = 0;
  crc = EPS_crc((uint8_t *)&eps_master_packet, 0, 3);
  eps_master_packet.crc_l = (uint8_t)crc & 0xFF;
  eps_master_packet.crc_h = (uint8_t)((crc >> 8) & 0xFF);

  /* Send Master Read Packet */
  UART_putb(UART_EPS, (char *)&eps_master_packet, 5);

  bytes_expected = 6;
  bytes_received = 0;
  RTC_getTime(&current_time);
  timeout = current_time;
  while(current_time < (timeout + 2))
  {
    if(UART_getc_nonblocking(UART_EPS, &c))
    {
      ((char *)(data))[bytes_received] = c;
      if(++bytes_received == bytes_expected)
      {
        break;
      }
    }
    RTC_getTime(&current_time);
  }
  if(bytes_received != bytes_expected)
  {
    return false;
  }

  crc = EPS_crc((uint8_t *)data, 0, 4);
  if(crc != data->crc)
  {
    return false;
  }

  return true;
}

/* Implementation copied from eps-firmware/PowerMcu/PowerMcu/util/crc.c */
static uint16_t EPS_crc(uint8_t *message, int32_t offset, int32_t length)
{
  uint16_t crcFull = 0xFFFF;
  int32_t i, j;

  for (i = offset; i < length; i++)
  {
    crcFull = (uint16_t)(crcFull ^ message[i]);

    for (j = 0; j < 8; j++)
    {
      uint8_t crcLsb = (uint8_t)(crcFull & 0x0001);
      crcFull = (uint16_t)((crcFull >> 1) & 0x7FFF);

      if (crcLsb == 1)
        crcFull = (uint16_t)(crcFull ^ 0xA001);
    }
  }
  return crcFull;
}