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AP_RangeFinder: update uLanding driver for new firmware data format

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This commit is contained in:
davidaroyer 2017-09-06 12:43:33 -05:00 committed by Andrew Tridgell
parent 8e53fb2a78
commit 039b295c66
2 changed files with 134 additions and 14 deletions
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140
libraries/AP_RangeFinder/AP_RangeFinder_uLanding.cpp
View File

@ -18,6 +18,9 @@
#include <AP_SerialManager/AP_SerialManager.h>
#include <ctype.h>
#define ULANDING_HDR 254 // Header Byte from uLanding (0xFE)
#define ULANDING_HDR_V0 72 // Header Byte for beta V0 of uLanding (0x48)
extern const AP_HAL::HAL& hal;
/*
@ -46,6 +49,87 @@ bool AP_RangeFinder_uLanding::detect(RangeFinder &_ranger, uint8_t instance, AP_
return serial_manager.find_serial(AP_SerialManager::SerialProtocol_Aerotenna_uLanding, 0) != nullptr;
}
/*
detect uLanding Firmware Version
*/
bool AP_RangeFinder_uLanding::detect_version(void)
{
if (_version_known) {
// return true if we've already detected the uLanding version
return true;
} else if (uart == nullptr) {
return false;
}
bool hdr_found = false;
uint8_t byte1 = 0;
uint8_t count = 0;
// read any available data from uLanding
int16_t nbytes = uart->available();
while (nbytes-- > 0) {
uint8_t c = uart->read();
if (((c == ULANDING_HDR_V0) || (c == ULANDING_HDR)) && !hdr_found) {
byte1 = c;
hdr_found = true;
count++;
} else if (hdr_found) {
if (byte1 == ULANDING_HDR_V0) {
if (++count < 4) {
/* need to collect 4 bytes to check for recurring
* header byte in the old 3-byte data format
*/
continue;
} else {
if (c == byte1) {
// if header byte is recurring, set uLanding Version
_version = 0;
_header = ULANDING_HDR_V0;
_version_known = true;
return true;
} else {
/* if V0 header byte didn't occur again on 4th byte,
* start the search again for a header byte
*/
count = 0;
byte1 = 0;
hdr_found = false;
}
}
} else {
if ((c & 0x80) || (c == ULANDING_HDR_V0)) {
/* Though unlikely, it is possible we could find ULANDING_HDR
* in a data byte from the old 3-byte format. In this case,
* either the next byte is another data byte (which by default
* is of the form 0x1xxxxxxx), or the next byte is the old
* header byte (ULANDING_HDR_V0). In this case, start the search
* again for a header byte.
*/
count = 0;
byte1 = 0;
hdr_found = false;
} else {
/* if this second byte passes the above if statement, this byte
* is the version number
*/
_version = c;
_header = ULANDING_HDR;
_version_known = true;
return true;
}
}
}
}
/* return false if we've gone through all available data
* and haven't detected a uLanding firmware version
*/
return false;
}
// read - return last value measured by sensor
bool AP_RangeFinder_uLanding::get_reading(uint16_t &reading_cm)
{
@ -53,28 +137,53 @@ bool AP_RangeFinder_uLanding::get_reading(uint16_t &reading_cm)
return false;
}
if (!detect_version()) {
// return false if uLanding version check failed
return false;
}
// read any available lines from the uLanding
float sum = 0;
uint16_t count = 0;
uint8_t index = 0;
bool hdr_found = false;
int16_t nbytes = uart->available();
while (nbytes-- > 0) {
uint8_t c = uart->read();
// ok, we have located start byte
if (c == 72 && index == 0) {
if ((c == _header) && !hdr_found) {
// located header byte
linebuf_len = 0;
index = 1;
hdr_found = true;
}
// now it is ready to decode index information
if (index == 1) {
linebuf[linebuf_len] = c;
linebuf_len ++;
if (linebuf_len == 3) {
index = 0;
sum += (linebuf[2]&0x7F) *128 + (linebuf[1]&0x7F);
// decode index information
if (hdr_found) {
linebuf[linebuf_len++] = c;
/* don't process linebuf until we've collected six bytes of data
* (or 3 bytes for Version 0 firmware)
*/
if ((linebuf_len < (sizeof(linebuf)/sizeof(linebuf[0]))) ||
(_version == 0 && linebuf_len < 3)) {
continue;
} else {
if (_version == 0) {
// parse data from Firmware Version #0
sum += (linebuf[2]&0x7F)*128 + (linebuf[1]&0x7F);
count++;
} else {
// evaluate checksum
if (((linebuf[1] + linebuf[2] + linebuf[3] + linebuf[4]) & 0xFF) == linebuf[5]) {
// if checksum passed, parse data from Firmware Version #1
sum += linebuf[3]*256 + linebuf[2];
count++;
}
}
hdr_found = false;
linebuf_len = 0;
count ++;
}
}
}
@ -83,7 +192,12 @@ bool AP_RangeFinder_uLanding::get_reading(uint16_t &reading_cm)
return false;
}
reading_cm = 2.5f * sum / count;
reading_cm = sum / count;
if (_version == 0) {
reading_cm *= 2.5f;
}
return true;
}

8
libraries/AP_RangeFinder/AP_RangeFinder_uLanding.h
View File

@ -18,11 +18,17 @@ public:
void update(void);
private:
// detect uLanding Firmware Version
bool detect_version(void);
// get a reading
bool get_reading(uint16_t &reading_cm);
AP_HAL::UARTDriver *uart = nullptr;
uint32_t last_reading_ms = 0;
uint8_t linebuf[10];
uint8_t linebuf[6];
uint8_t linebuf_len = 0;
bool _version_known;
uint8_t _header;
uint8_t _version;
};