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Update pmw3360 comments to match the datasheet better, fix delays. (#15682)

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uqs 2022-01-02 09:06:17 +01:00 • committed by GitHub
parent 367e2bb0ff
commit 8b44eaa63e
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4 changed files with 26 additions and 16 deletions
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34
drivers/sensors/pmw3360.c
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@ -78,8 +78,12 @@
#define CPI_STEP 100
// clang-format on
// limits to 0--119, resulting in a CPI range of 100 -- 12000 (as only steps of 100 are possible).
// Note that for the PMW3389DM chip, the step size is 50 and supported range is
// up to 16000. The datasheet does not indicate the minimum CPI though, neither
// whether this uses 2 bytes (as 16000/50 == 320)
#ifndef MAX_CPI
# define MAX_CPI 0x77 // limits to 0--119, should be max cpi/100
# define MAX_CPI 0x77
#endif
bool _inBurst = false;
@ -91,6 +95,7 @@ void print_byte(uint8_t byte) { dprintf("%c%c%c%c%c%c%c%c|", (byte & 0x80 ? '1'
bool pmw3360_spi_start(void) {
bool status = spi_start(PMW3360_CS_PIN, PMW3360_SPI_LSBFIRST, PMW3360_SPI_MODE, PMW3360_SPI_DIVISOR);
// tNCS-SCLK, 120ns
wait_us(1);
return status;
}
@ -106,12 +111,12 @@ spi_status_t pmw3360_write(uint8_t reg_addr, uint8_t data) {
spi_status_t status = spi_write(reg_addr | 0x80);
status = spi_write(data);
// tSCLK-NCS for write operation
// tSCLK-NCS for write operation is 35us
wait_us(35);
spi_stop();
// tSWW/tSWR (=180us) minus tSCLK-NCS. Could be shortened, but is looks like a safe lower bound
wait_us(145);
spi_stop();
return status;
}
@ -119,15 +124,16 @@ uint8_t pmw3360_read(uint8_t reg_addr) {
pmw3360_spi_start();
// send adress of the register, with MSBit = 0 to indicate it's a read
spi_write(reg_addr & 0x7f);
// tSRAD (=160us)
wait_us(160);
uint8_t data = spi_read();
// tSCLK-NCS for read operation is 120ns
wait_us(1);
spi_stop();
// tSRW/tSRR (=20us) minus tSCLK-NCS
wait_us(19);
spi_stop();
return data;
}
@ -149,7 +155,7 @@ bool pmw3360_init(void) {
spi_stop();
wait_us(40);
// reboot
// power up, need to first drive NCS high then low, see above.
pmw3360_write(REG_Power_Up_Reset, 0x5a);
wait_ms(50);
@ -190,6 +196,9 @@ bool pmw3360_init(void) {
}
void pmw3360_upload_firmware(void) {
// Datasheet claims we need to disable REST mode first, but during startup
// it's already disabled and we're not turning it on ...
//pmw3360_write(REG_Config2, 0x00); // disable REST mode
pmw3360_write(REG_SROM_Enable, 0x1d);
wait_ms(10);
@ -242,15 +251,20 @@ report_pmw3360_t pmw3360_read_burst(void) {
pmw3360_spi_start();
spi_write(REG_Motion_Burst);
wait_us(35); // waits for tSRAD
wait_us(35); // waits for tSRAD_MOTBR
report.motion = spi_read();
spi_write(0x00); // skip Observation
spi_read(); // skip Observation
// delta registers
report.dx = spi_read();
report.mdx = spi_read();
report.dy = spi_read();
report.mdy = spi_read();
if (report.motion & 0b111) { // panic recovery, sometimes burst mode works weird.
_inBurst = false;
}
spi_stop();
#ifdef CONSOLE_ENABLE
@ -271,9 +285,5 @@ report_pmw3360_t pmw3360_read_burst(void) {
report.dy |= (report.mdy << 8);
report.dy = report.dy * -1;
if (report.motion & 0b111) { // panic recovery, sometimes burst mode works weird.
_inBurst = false;
}
return report;
}