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/* Copyright 2021 Colin Lam (Ploopy Corporation)
* Copyright 2020 Christopher Courtney, aka Drashna Jael're (@drashna) <drashna@live.com>
* Copyright 2019 Sunjun Kim
* Copyright 2019 Hiroyuki Okada
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "pmw3320.h"
#include "wait.h"
#include "debug.h"
#include "gpio.h"
void pmw3320_init(void) {
// Initialize sensor serial pins.
gpio_set_pin_output(PMW3320_SCLK_PIN);
gpio_set_pin_output(PMW3320_SDIO_PIN);
gpio_set_pin_output(PMW3320_CS_PIN);
// reboot the sensor.
pmw3320_write_reg(REG_Power_Up_Reset, 0x5a);
// wait maximum time before sensor is ready.
// this ensures that the sensor is actually ready after reset.
wait_ms(55);
// read a burst from the sensor and then discard it.
// gets the sensor ready for write commands
// (for example, setting the dpi).
pmw3320_read_burst();
// Pretty sure that this shouldn't be in the driver.
// Probably device specific?
// Set rest mode to default
pmw3320_write_reg(REG_Rest_Mode_Status, 0x00);
// Set LED to be always on
pmw3320_write_reg(REG_Led_Control, 0x4);
// Disable rest mode
pmw3320_write_reg(REG_Performance, 0x80);
}
// Perform a synchronization with sensor.
// Just as with the serial protocol, this is used by the slave to send a
// synchronization signal to the master.
void pmw3320_sync(void) {
gpio_write_pin_low(PMW3320_CS_PIN);
wait_us(1);
gpio_write_pin_high(PMW3320_CS_PIN);
}
void pmw3320_cs_select(void) {
gpio_write_pin_low(PMW3320_CS_PIN);
}
void pmw3320_cs_deselect(void) {
gpio_write_pin_high(PMW3320_CS_PIN);
}
uint8_t pmw3320_serial_read(void) {
gpio_set_pin_input(PMW3320_SDIO_PIN);
uint8_t byte = 0;
for (uint8_t i = 0; i < 8; ++i) {
gpio_write_pin_low(PMW3320_SCLK_PIN);
wait_us(1);
byte = (byte << 1) | gpio_read_pin(PMW3320_SDIO_PIN);
gpio_write_pin_high(PMW3320_SCLK_PIN);
wait_us(1);
}
return byte;
}
void pmw3320_serial_write(uint8_t data) {
gpio_set_pin_output(PMW3320_SDIO_PIN);
for (int8_t b = 7; b >= 0; b--) {
gpio_write_pin_low(PMW3320_SCLK_PIN);
if (data & (1 << b))
gpio_write_pin_high(PMW3320_SDIO_PIN);
else
gpio_write_pin_low(PMW3320_SDIO_PIN);
wait_us(2);
gpio_write_pin_high(PMW3320_SCLK_PIN);
}
// This was taken from ADNS5050 driver.
// There's no any info in PMW3320 datasheet about this...
// tSWR. See page 15 of the ADNS5050 spec sheet.
// Technically, this is only necessary if the next operation is an SDIO
// read. This is not guaranteed to be the case, but we're being lazy.
wait_us(4);
// Note that tSWW is never necessary. All write operations require at
// least 32us, which exceeds tSWW, so there's never a need to wait for it.
}
// Read a byte of data from a register on the sensor.
uint8_t pmw3320_read_reg(uint8_t reg_addr) {
pmw3320_cs_select();
pmw3320_serial_write(reg_addr);
uint8_t byte = pmw3320_serial_read();
// This was taken directly from ADNS5050 driver...
// tSRW & tSRR. See page 15 of the ADNS5050 spec sheet.
// Technically, this is only necessary if the next operation is an SDIO
// read or write. This is not guaranteed to be the case.
// Honestly, this wait could probably be removed.
wait_us(1);
pmw3320_cs_deselect();
return byte;
}
void pmw3320_write_reg(uint8_t reg_addr, uint8_t data) {
pmw3320_cs_select();
pmw3320_serial_write(0b10000000 | reg_addr);
pmw3320_serial_write(data);
pmw3320_cs_deselect();
}
report_pmw3320_t pmw3320_read_burst(void) {
pmw3320_cs_select();
report_pmw3320_t data;
data.dx = 0;
data.dy = 0;
pmw3320_serial_write(REG_Motion_Burst);
uint8_t x = pmw3320_serial_read();
uint8_t y = pmw3320_serial_read();
// Probably burst mode may include contents of delta_xy register,
// which contain HI parts of x/y deltas, but I had no luck finding it.
// Probably it's required to activate 12-bit mode to access this data.
// So we end burst mode early to not read unneeded information.
pmw3320_cs_deselect();
data.dx = convert_twoscomp(x);
data.dy = convert_twoscomp(y);
return data;
}
// Convert a two's complement byte from an unsigned data type into a signed
// data type.
int8_t convert_twoscomp(uint8_t data) {
if ((data & 0x80) == 0x80)
return -128 + (data & 0x7F);
else
return data;
}
uint16_t pmw3320_get_cpi(void) {
uint8_t cpival = pmw3320_read_reg(REG_Resolution);
// 0x1F is an inversion of 0x20 which is 0b100000
return (uint16_t)((cpival & 0x1F) * PMW3320_CPI_STEP);
}
void pmw3320_set_cpi(uint16_t cpi) {
uint8_t cpival = constrain((cpi / PMW3320_CPI_STEP), (PMW3320_CPI_MIN / PMW3320_CPI_STEP), (PMW3320_CPI_MAX / PMW3320_CPI_STEP)) - 1U;
// Fifth bit is probably a control bit.
// PMW3320 datasheet don't have any info on this, so this is a pure guess.
pmw3320_write_reg(REG_Resolution, 0x20 | cpival);
}
bool pmw3320_check_signature(void) {
uint8_t pid = pmw3320_read_reg(REG_Product_ID);
uint8_t pid2 = pmw3320_read_reg(REG_Inverse_Product_ID);
return (pid == 0x3b && pid2 == 0xc4);
}
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