commit 833bf9ab2f214a07640eb959533e33fd8f5e56c4
parent 9e3269081a984b88bca97bc53699526c99c1693f
Author: mntmn <lukas@mntmn.com>
Date: Thu, 25 Jun 2020 17:40:27 +0200
lpc-fw: implement min/max charge level tracking and gauge.
Diffstat:
1 file changed, 100 insertions(+), 22 deletions(-)
diff --git a/reform2-lpc-fw/src/boards/reform2/board_reform2.c b/reform2-lpc-fw/src/boards/reform2/board_reform2.c
@@ -28,7 +28,7 @@
#include "protocol/protocol.h"
#endif
-//#define REF2_DEBUG 0
+//#define REF2_DEBUG 1
#define INA260_ADDRESS 0x4e
#define LTC4162F_ADDRESS 0x68
@@ -117,12 +117,13 @@ uint8_t calc_pec(uint8_t d, uint8_t pec) {
return pec;
}
-
+// main charger state machine
enum state_t {
ST_CHARGE,
ST_OVERVOLTED,
ST_UNDERVOLTED,
- ST_MISSING
+ ST_MISSING,
+ ST_FULLY_CHARGED
};
// charging state machine
@@ -132,15 +133,21 @@ int charge_current = 1;
uint32_t cur_second = 0;
uint32_t last_second = 0;
-float ampSecs = 10*3600.0;
+// 1.8A x 3600 seconds/hour
+#define MAX_CAPACITY (1.8)*3600.0
+float capacity_max_ampsecs = MAX_CAPACITY;
+float capacity_accu_ampsecs = MAX_CAPACITY;
+float capacity_min_ampsecs = 430*3.6; // TODO save this in flash after learning
float volts = 0;
float current = 0;
unsigned long lastTime = 0;
char uartBuffer[255] = {0};
float cells_v[8] = {0,0,0,0,0,0,0,0};
int num_undervolted_cells = 0;
+int num_undervolted_critical_cells = 0;
int num_overvolted_cells = 0;
int num_missing_cells = 0;
+uint8_t reached_full_charge = 0;
uint16_t discharge_bits = 0;
uint16_t overvoltage_bits = 0;
uint16_t undervoltage_bits = 0;
@@ -149,8 +156,10 @@ uint8_t spir[64];
#define OVERVOLTAGE_START_VALUE 3.61
#define OVERVOLTAGE_STOP_VALUE 3.55
-#define UNDERVOLTAGE_VALUE 2.6
+#define UNDERVOLTAGE_VALUE 2.55
+#define UNDERVOLTAGE_CRITICAL_VALUE 2.4
#define MISSING_VALUE 5
+#define FULLY_CHARGED_VOLTAGE (3.5*8.0)
void measure_cell_voltages_and_control_discharge() {
// delay is measured in "ticks", which are basically ms?
@@ -171,7 +180,8 @@ void measure_cell_voltages_and_control_discharge() {
// we're in normal charge mode, so remove charge current limit
LPC_GPIO->SET[1] |= (1 << 25);
} else {
- // we're discharging (balancing), so limit charge current
+ // we're discharging (balancing), or full charged,
+ // so limit charge current
// also don't charge if we have missing cells
LPC_GPIO->CLR[1] |= (1 << 25);
}
@@ -221,6 +231,7 @@ void measure_cell_voltages_and_control_discharge() {
num_missing_cells = 0;
num_undervolted_cells = 0;
num_overvolted_cells = 0;
+ num_undervolted_critical_cells = 0;
missing_bits = 0;
undervoltage_bits = 0;
@@ -238,6 +249,10 @@ void measure_cell_voltages_and_control_discharge() {
else if (cells_v[i] < UNDERVOLTAGE_VALUE) {
undervoltage_bits |= (1<<i);
num_undervolted_cells++;
+
+ if (cells_v[i] < UNDERVOLTAGE_CRITICAL_VALUE) {
+ num_undervolted_critical_cells++;
+ }
}
}
@@ -285,7 +300,7 @@ void measure_and_accumulate_current() {
lastTime = thisTime;
// decrease estimated battery capacity
- ampSecs -= current*(secondsPassed);
+ capacity_accu_ampsecs -= current*(secondsPassed);
}
} else {
// timer uninitialized or timer wrap
@@ -293,7 +308,7 @@ void measure_and_accumulate_current() {
}
#ifdef REF2_DEBUG
- sprintf(uartBuffer,"\033[H\033[2JINA Ah: %f V: %f A: %f\r\n",ampSecs/3600,volts,current);
+ sprintf(uartBuffer,"\033[H\033[2JINA Ah: %f V: %f A: %f\r\n",capacity_accu_ampsecs/3600,volts,current);
uartSend((uint8_t *)uartBuffer, strlen(uartBuffer));
#endif
}
@@ -311,17 +326,19 @@ void configure_charger(int charge_current) {
}
void turn_som_power_on(void) {
+ LPC_GPIO->CLR[1] = (1 << 28); // hold in reset
LPC_GPIO->SET[1] = (1 << 16); // 3v3, high = on
- // FIXME this turns 1v5 off :/
- LPC_GPIO->SET[0] = (1 << 20); // PCIe, low = on
+ LPC_GPIO->SET[0] = (1 << 20); // PCIe, high = on
LPC_GPIO->SET[1] = (1 << 15); // 5v, high = on
LPC_GPIO->SET[1] = (1 << 19); // 1v2, high = on
+ LPC_GPIO->SET[1] = (1 << 28); // release reset
}
void turn_som_power_off(void) {
+ LPC_GPIO->CLR[1] = (1 << 28); // hold in reset
LPC_GPIO->CLR[1] = (1 << 19); // 1v2, high = on
LPC_GPIO->CLR[1] = (1 << 15); // 5v, high = on
- LPC_GPIO->CLR[0] = (1 << 20); // PCIe, low = on
+ LPC_GPIO->CLR[0] = (1 << 20); // PCIe, high = on
LPC_GPIO->CLR[1] = (1 << 16); // 3v3, high = on
// FIXME experiment: temp. disable charger to reset its timers
@@ -375,14 +392,20 @@ void boardInit(void)
// 1V2 regulator on/off
LPC_GPIO->DIR[1] |= (1 << 19);
// PCIe 1 power supply transistor
- LPC_GPIO->DIR[0] |= (1 << 20);
+ LPC_GPIO->DIR[0] |= (1 << 20);
+
+ // IMX Wake
+ LPC_GPIO->DIR[1] |= (1 << 24);
+ // IMX Reset
+ LPC_GPIO->DIR[1] |= (1 << 28);
+
// RNG/SS pin of LTC4020: control/limit charge current
LPC_GPIO->DIR[1] |= (1 << 25);
// start with low charge current
LPC_GPIO->CLR[1] |= (1 << 25);
- turn_som_power_on();
+ turn_som_power_off();
uartInit(CFG_UART_BAUDRATE);
i2cInit(I2CMASTER);
@@ -395,7 +418,7 @@ void boardInit(void)
// SPI chip select
LPC_GPIO->DIR[1] |= (1 << 23);
LPC_GPIO->SET[1] = (1 << 23); // active low
-
+
#ifdef REF2_DEBUG
sprintf(uartBuffer, "\r\nMNT Reform 2.0 MCU initialized.\r\n");
uartSend((uint8_t*)uartBuffer, strlen(uartBuffer));
@@ -517,8 +540,10 @@ void handle_commands() {
sprintf(uartBuffer,"undervolt [%d]\r",cycles_in_state);
} else if (state == ST_MISSING) {
sprintf(uartBuffer,"cell missing [%d]\r",cycles_in_state);
- } else if (state == ST_MISSING) {
- sprintf(uartBuffer,"unknown [%d]\r",cycles_in_state);
+ } else if (state == ST_FULLY_CHARGED) {
+ sprintf(uartBuffer,"fully charged [%d]\r",cycles_in_state);
+ } else {
+ sprintf(uartBuffer,"unknown %d [%d]\r",state,cycles_in_state);
}
uartSend((uint8_t*)uartBuffer, strlen(uartBuffer));
}
@@ -539,13 +564,35 @@ void handle_commands() {
uartSend((uint8_t*)uartBuffer, strlen(uartBuffer));
}
else if (remote_cmd == 'C') {
- // set/get battery capacity (mAh)
- if (cmd_number>0) {
- ampSecs = ((float)cmd_number)*3.6;
- }
- sprintf(uartBuffer,"%d\r\n",(int)(ampSecs/3.6));
+ // get battery capacity (mAh)
+ sprintf(uartBuffer,"%d/%d/%d\r\n",
+ (int)(capacity_accu_ampsecs/3.6),
+ (int)(capacity_min_ampsecs/3.6),
+ (int)(capacity_max_ampsecs/3.6));
uartSend((uint8_t*)uartBuffer, strlen(uartBuffer));
}
+ else if (remote_cmd == 'g') {
+ // get fuel gauge (percent)
+ if (reached_full_charge > 0) {
+ int percentage = 0;
+ if (capacity_accu_ampsecs <= capacity_min_ampsecs) {
+ percentage = 0;
+ } else if (capacity_accu_ampsecs >= capacity_max_ampsecs) {
+ percentage = 100;
+ } else {
+ percentage = (int)(100.0*((float)capacity_accu_ampsecs - (float)capacity_min_ampsecs) / (float)capacity_max_ampsecs);
+ }
+
+ sprintf(uartBuffer,"%d%%\r\n", percentage);
+ uartSend((uint8_t*)uartBuffer, strlen(uartBuffer));
+ } else {
+ // if we never reached full charge,
+ // we don't really know where we are.
+
+ sprintf(uartBuffer,"? %%\r\n");
+ uartSend((uint8_t*)uartBuffer, strlen(uartBuffer));
+ }
+ }
else if (remote_cmd == 'e') {
// toggle serial echo
cmd_echo = cmd_number?1:0;
@@ -604,9 +651,18 @@ int main(void)
// some cool-off time
if (num_missing_cells > 0) {
state = ST_MISSING;
+ // if cells were unplugged, we don't know the capacity anymore.
+ reached_full_charge = 0;
cycles_in_state = 0;
}
else if (num_undervolted_cells > 0) {
+ // when transitioning to undervoltage, we assume we reached the bottom
+ // of usable capacity, so record it
+ // but only if we reached top charge once, or our counter will
+ // be off.
+ if (reached_full_charge > 0) {
+ capacity_min_ampsecs = capacity_accu_ampsecs;
+ }
state = ST_UNDERVOLTED;
cycles_in_state = 0;
}
@@ -614,13 +670,25 @@ int main(void)
state = ST_OVERVOLTED;
cycles_in_state = 0;
}
+ else if (volts >= FULLY_CHARGED_VOLTAGE) {
+ // when transitioning to fully charged, we assume that we're at max capacity
+ capacity_accu_ampsecs = capacity_max_ampsecs;
+ state = ST_FULLY_CHARGED;
+ reached_full_charge = 1;
+ cycles_in_state = 0;
+ }
}
}
else if (state == ST_UNDERVOLTED) {
// TODO: issue alert -- switch off system if critical
reset_discharge_bits();
- turn_som_power_off();
+ // TODO: find safe heuristic. here we turn off if half
+ // of the cells are undervolted.
+ if (num_undervolted_critical_cells > 0 || num_undervolted_cells > 3) {
+ turn_som_power_off();
+ }
+
if (cycles_in_state > 5) {
state = ST_CHARGE;
cycles_in_state = 0;
@@ -646,6 +714,16 @@ int main(void)
}
}
}
+ else if (state == ST_FULLY_CHARGED) {
+ // fully charged. resume charging once we're 0.2mV
+ // below fully charged state
+ if (cycles_in_state > 5) {
+ if (volts < (FULLY_CHARGED_VOLTAGE - 0.2)) {
+ state = ST_CHARGE;
+ cycles_in_state = 0;
+ }
+ }
+ }
handle_commands();
cur_second = delayGetSecondsActive();
