h3n3/klipper
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

adxl345: Compress each sample from 6 bytes to 5 bytes

Browse Source 
Transmit data from mcu to host using 5 bytes per sample and up to 10
samples per message block.  This improves bandwidth efficiency.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>
This commit is contained in:
Kevin O'Connor
2021-08-22 16:24:16 -04:00
parent e34137582d
commit 22167f9510
2 changed files with 54 additions and 20 deletions
Download Patch File Download Diff File Expand all files Collapse all files

30
src/sensor_adxl345.c
View File

@@ -18,7 +18,7 @@ struct adxl345 {
struct spidev_s *spi;
uint16_t sequence, limit_count;
uint8_t flags, data_count;
uint8_t data[48];
uint8_t data[50];
};
enum {
@@ -85,17 +85,37 @@ adxl_reschedule_timer(struct adxl345 *ax)
#define AM_READ 0x80
#define AM_MULTI 0x40
#define SET_FIFO_CTL 0x90
// Query accelerometer data
static void
adxl_query(struct adxl345 *ax, uint8_t oid)
{
// Read data
uint8_t msg[9] = { AR_DATAX0 | AM_READ | AM_MULTI, 0, 0, 0, 0, 0, 0, 0, 0 };
spidev_transfer(ax->spi, 1, sizeof(msg), msg);
memcpy(&ax->data[ax->data_count], &msg[1], 6);
ax->data_count += 6;
if (ax->data_count + 6 > ARRAY_SIZE(ax->data))
adxl_report(ax, oid);
// Extract x, y, z measurements
uint_fast8_t fifo_status = msg[8] & ~0x80; // Ignore trigger bit
uint8_t *d = &ax->data[ax->data_count];
if (((msg[2] & 0xf0) && (msg[2] & 0xf0) != 0xf0)
|| ((msg[4] & 0xf0) && (msg[4] & 0xf0) != 0xf0)
|| ((msg[6] & 0xf0) && (msg[6] & 0xf0) != 0xf0)
|| (msg[7] != SET_FIFO_CTL) || (fifo_status > 32)) {
// Data error - may be a CS, MISO, MOSI, or SCLK glitch
d[0] = d[1] = d[2] = d[3] = d[4] = 0xff;
fifo_status = 0;
} else {
// Copy data
d[0] = msg[1]; // x low bits
d[1] = msg[3]; // y low bits
d[2] = msg[5]; // z low bits
d[3] = (msg[2] & 0x1f) | (msg[6] << 5); // x high bits and z high bits
d[4] = (msg[4] & 0x1f) | ((msg[6] << 2) & 0x60); // y high and z high
}
ax->data_count += 5;
if (ax->data_count + 5 > ARRAY_SIZE(ax->data))
adxl_report(ax, oid);
// Check fifo status
if (fifo_status >= 31)
ax->limit_count++;
if (fifo_status > 1 && fifo_status <= 32) {