Chen Wei Ting
/
zerotorque_final
zero torque and encoder
Fork of LSM9DS1_project_5_zerotorque by
encoder.cpp@0:c23e915f255b, 2018-08-05 (annotated)
- Committer:
- JJting
- Date:
- Sun Aug 05 13:15:56 2018 +0000
- Revision:
- 0:c23e915f255b
ver1
Who changed what in which revision?
User | Revision | Line number | New contents of line |
---|---|---|---|
JJting | 0:c23e915f255b | 1 | #include "mbed.h" |
JJting | 0:c23e915f255b | 2 | #include "encoder.h" |
JJting | 0:c23e915f255b | 3 | |
JJting | 0:c23e915f255b | 4 | DigitalOut encoder_cs(D9); |
JJting | 0:c23e915f255b | 5 | //SPI spi_encoder(D11, D12, D13); // mosi, miso, sclk |
JJting | 0:c23e915f255b | 6 | SPI spi_encoder(D4, D5, D3); // mosi, miso, sclk |
JJting | 0:c23e915f255b | 7 | |
JJting | 0:c23e915f255b | 8 | unsigned short encoder_value; |
JJting | 0:c23e915f255b | 9 | unsigned short angle = 0; |
JJting | 0:c23e915f255b | 10 | unsigned short angle_old; |
JJting | 0:c23e915f255b | 11 | int angle_dif; |
JJting | 0:c23e915f255b | 12 | int a_dif; |
JJting | 0:c23e915f255b | 13 | int Angle = 0; |
JJting | 0:c23e915f255b | 14 | unsigned short k = 0; |
JJting | 0:c23e915f255b | 15 | |
JJting | 0:c23e915f255b | 16 | void init_SPI_encoder() |
JJting | 0:c23e915f255b | 17 | { |
JJting | 0:c23e915f255b | 18 | spi_encoder.format(16,3); |
JJting | 0:c23e915f255b | 19 | spi_encoder.frequency(1000000); // 1MHz clock rate |
JJting | 0:c23e915f255b | 20 | } |
JJting | 0:c23e915f255b | 21 | |
JJting | 0:c23e915f255b | 22 | void init_encoder() |
JJting | 0:c23e915f255b | 23 | { |
JJting | 0:c23e915f255b | 24 | encoder_cs = 1; // high:disable the device |
JJting | 0:c23e915f255b | 25 | } |
JJting | 0:c23e915f255b | 26 | |
JJting | 0:c23e915f255b | 27 | void angle_measure() |
JJting | 0:c23e915f255b | 28 | { |
JJting | 0:c23e915f255b | 29 | encoder_cs = 0; // Select the device by seting chip select low |
JJting | 0:c23e915f255b | 30 | encoder_value = spi_encoder.write(0x00); |
JJting | 0:c23e915f255b | 31 | angle = encoder_value >> 3; |
JJting | 0:c23e915f255b | 32 | encoder_cs = 1; // Deselect the device |
JJting | 0:c23e915f255b | 33 | |
JJting | 0:c23e915f255b | 34 | if (k == 0) { |
JJting | 0:c23e915f255b | 35 | Angle = 0; |
JJting | 0:c23e915f255b | 36 | angle_old = angle; |
JJting | 0:c23e915f255b | 37 | k++; |
JJting | 0:c23e915f255b | 38 | } else { |
JJting | 0:c23e915f255b | 39 | angle_dif = angle_count(angle, angle_old); |
JJting | 0:c23e915f255b | 40 | Angle = Angle + angle_dif; |
JJting | 0:c23e915f255b | 41 | angle_old = angle; |
JJting | 0:c23e915f255b | 42 | } |
JJting | 0:c23e915f255b | 43 | } |
JJting | 0:c23e915f255b | 44 | |
JJting | 0:c23e915f255b | 45 | int angle_count(unsigned short now,unsigned short old) |
JJting | 0:c23e915f255b | 46 | { |
JJting | 0:c23e915f255b | 47 | a_dif = now - old; |
JJting | 0:c23e915f255b | 48 | if (a_dif > 4096/2) { |
JJting | 0:c23e915f255b | 49 | a_dif = -(4096 - a_dif); |
JJting | 0:c23e915f255b | 50 | } else if (a_dif < -4096/2) { |
JJting | 0:c23e915f255b | 51 | a_dif = 4096 + a_dif; |
JJting | 0:c23e915f255b | 52 | } else { |
JJting | 0:c23e915f255b | 53 | a_dif = a_dif; |
JJting | 0:c23e915f255b | 54 | } |
JJting | 0:c23e915f255b | 55 | return a_dif; |
JJting | 0:c23e915f255b | 56 | } |