EIE4-FYP/demo/amp.cpp

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2023-06-24 19:53:04 +00:00
#include "amp"
#include <generated/csr.h>
#include <libbase/i2c.h>
#include <stdint.h>
#ifdef CONFIG_HAS_I2C
#define I2C_DELAY(n) busy_wait_us(n * (250000 / I2C_FREQ_HZ))
static inline void i2c_oe_scl_sda(bool oe, bool scl, bool sda) {
i2c_w_write(
((oe & 1) << CSR_I2C_W_OE_OFFSET) |
((scl & 1) << CSR_I2C_W_SCL_OFFSET) |
((sda & 1) << CSR_I2C_W_SDA_OFFSET));
}
// START condition: 1-to-0 transition of SDA when SCL is 1
static void i2c_start(void) {
i2c_oe_scl_sda(1, 1, 1);
I2C_DELAY(1);
i2c_oe_scl_sda(1, 1, 0);
I2C_DELAY(1);
i2c_oe_scl_sda(1, 0, 0);
I2C_DELAY(1);
}
// STOP condition: 0-to-1 transition of SDA when SCL is 1
static void i2c_stop(void) {
i2c_oe_scl_sda(1, 0, 0);
I2C_DELAY(1);
i2c_oe_scl_sda(1, 1, 0);
I2C_DELAY(1);
i2c_oe_scl_sda(1, 1, 1);
I2C_DELAY(1);
i2c_oe_scl_sda(0, 1, 1);
}
// Call when in the middle of SCL low, advances one clk period
static void i2c_transmit_bit(int value) {
i2c_oe_scl_sda(1, 0, value);
I2C_DELAY(1);
i2c_oe_scl_sda(1, 1, value);
I2C_DELAY(2);
i2c_oe_scl_sda(1, 0, value);
I2C_DELAY(1);
}
// Call when in the middle of SCL low, advances one clk period
static int i2c_receive_bit(void) {
int value;
i2c_oe_scl_sda(0, 0, 0);
I2C_DELAY(1);
i2c_oe_scl_sda(0, 1, 0);
I2C_DELAY(1);
// read in the middle of SCL high
value = i2c_r_read() & 1;
I2C_DELAY(1);
i2c_oe_scl_sda(0, 0, 0);
I2C_DELAY(1);
return value;
}
// Send data byte and return 1 if slave sends ACK
static bool i2c_transmit_byte(unsigned char data) {
int i;
int ack;
// SCL should have already been low for 1/4 cycle
// Keep SDA low to avoid short spikes from the pull-ups
i2c_oe_scl_sda(1, 0, 0);
for (i = 0; i < 8; ++i) {
// MSB first
i2c_transmit_bit((data & (1 << 7)) != 0);
data <<= 1;
}
i2c_oe_scl_sda(0, 0, 0); // release line
ack = i2c_receive_bit();
// 0 from slave means ack
return ack == 0;
}
// Read data byte and send ACK if ack=1
static unsigned char i2c_receive_byte(bool ack) {
int i;
unsigned char data = 0;
for (i = 0; i < 8; ++i) {
data <<= 1;
data |= i2c_receive_bit();
}
i2c_transmit_bit(!ack);
i2c_oe_scl_sda(0, 0, 0); // release line
return data;
}
bool amp_init(void) {
return amp_write({0x00, 0x00, 0x07});
}
bool amp_read(amp_i2c &rcv) {
i2c_start();
if (!i2c_transmit_byte(I2C_ADDR_RD(0x28))) {
i2c_stop();
return false;
}
rcv.pot0 = i2c_receive_byte(true) & 0x3F;
rcv.pot1 = i2c_receive_byte(true) & 0x3F;
rcv.conf = i2c_receive_byte(false) & 0x3F;
i2c_stop();
return true;
}
bool amp_read_pot0(uint8_t &pot0) {
amp_i2c temp;
bool success = amp_read(temp);
pot0 = temp.pot0;
return success;
}
bool amp_read_pot1(uint8_t &pot1) {
amp_i2c temp;
bool success = amp_read(temp);
pot1 = temp.pot1;
return success;
}
bool amp_read_conf(uint8_t &conf) {
amp_i2c temp;
bool success = amp_read(temp);
conf = temp.conf;
return success;
}
bool amp_write(amp_i2c value) {
i2c_start();
if (!i2c_transmit_byte(I2C_ADDR_WR(0x28))) {
i2c_stop();
return true;
}
if (!i2c_transmit_byte(value.pot0)) {
i2c_stop();
return false;
}
if (!i2c_transmit_byte(value.pot1 | 0x40)) {
i2c_stop();
return false;
}
if (!i2c_transmit_byte(value.conf | 0x80)) {
i2c_stop();
return false;
}
i2c_stop();
return true;
}
bool amp_write_pot0(uint8_t value) {
amp_i2c temp;
bool success = amp_read(temp);
temp.pot0 = value;
return success & amp_write(temp);
}
bool amp_write_pot1(uint8_t value) {
amp_i2c temp;
bool success = amp_read(temp);
temp.pot1 = value;
return success & amp_write(temp);
}
bool amp_write_conf(uint8_t value) {
amp_i2c temp;
bool success = amp_read(temp);
temp.conf = value;
return success & amp_write(temp);
}
#endif