Hi
I am stuck and after 2 days of google and self struggle I am at a lost. Pretty sure i got the wiring, spi mode, MSBit and 10mHz settigs rite. When sending read "command' with adress with receiving data, it fails.
When I have the data in I can bit shift it to get desired data and work it into angular degress and carry on from there......but i am stuck at reading the data trough SPI.
Extract from programming manual
SPI Interface
The ...SPI interface...utilizing SPI mode 3.... two communication protocols. SPI
is selected when ISEL is brought to a logic high. This is easily accomplished by tying the ISEL pin directly to the BYP pin of the A1335, which provides a constant ≈2.8 V. .... maximize data throughput, up to fSCLK(max) of 10 MHz.
Extract from programming manual, this is where I am stuck.
Read Cycle Overview
Read cycles have two stages: a Read command, selecting a serial register address, followed by another Read command to transmit the data from the selected register. Both commands consist of a
1-bit sync (low), a 1-bit R/W asserted low, 6 address bits identifying the target register, and 8 data bits (all zeros because no data is
being written).
It goes on in folowing paragraph. pages 22,23 Link to manual
And my code attempt:
/* ******************************************************************************
* SPI read 3x A1335 rotation sensor chips with UNO and display on serial monitor
* Slave select pins 10 >ss1, 9 >ss2, 8 >ss3
*/
#include <SPI.h>
// set slave pins and variables
const int ss1 = 10;
const int ss2 = 9;
const int ss3 = 8;
uint16_t Ang_ss1 = 0;
uint16_t Ang_ss2 = 0;
uint16_t Ang_ss3 = 0;
/*SPI settings here and not declared globaly for attaching different
spi devices with difrent settings. Call transaction,begin with new
settings*/
SPISettings settingsA(10000000,MSBFIRST,SPI_MODE3);
void setup() {
//set slave pins High and as outputs
pinMode (ss1,OUTPUT);
digitalWrite (ss1,HIGH);
pinMode (ss2,OUTPUT);
digitalWrite (ss2,HIGH);
pinMode (ss3,OUTPUT);
digitalWrite (ss3,HIGH);
SPI.begin();
Serial.begin(9600);
}
void loop() {
SPI.beginTransaction(settingsA);
//select sensor 1 to 3 and read registers 0x20 and 0x21
digitalWrite (ss1,LOW); // sensor one read and store two bite data in ANG_ss1
Ang_ss1 = SPI.transfer(0b00100000); //read commnd "00" (00 & 0x20) adress register > did not work
Ang_ss1 = Ang_ss1 <<8; //shift over MSB's
Ang_ss1 |= SPI.transfer(0); //Fill lower bite
/*Ang_ss1 = SPI.transfer(0X20); //read first bite, shift and read second bite
Ang_ss1 = Angle_ss1 <<8;
Ang_ss1 =Ang_ss1 &SPI.transfer(0x21); //> did not work*/
digitalWrite (ss1,HIGH); //end read sensor one
/*digitalWrite (ss2,LOW); //repeat read for sensor two
Ang_ss2 = SPI.transfer(0x20);
digitalWrite (ss2,HIGH);
digitalWrite (ss3,LOW); // repeat for sensor three
Ang_ss3 = SPI.transfer16(0);
digitalWrite (ss3,HIGH);*/
SPI.endTransaction();
//De-bug code: display values from sensors
Serial.print(Ang_ss1); //Serial.print(Ang_ss1,BIN);
Serial.print("ss1 ");
Serial.print(Ang_ss2,BIN);
Serial.print("ss2 ");
Serial.print(Ang_ss3,BIN);
Serial.println("ss3");
// convert received angle values to angular degrees
// might have to bit shift or mask 4 MSB angle register
Serial.print(Ang_ss1*(360/4096));
Serial.print(" DEG ");
Serial.print(Ang_ss2*(360/4096));
Serial.print(" DEG ");
Serial.print(Ang_ss3*(360/4096));
Serial.println(" DEG");
delay (1000); // to read serial monitor for debugging
}
Note: When I attached MSO 5102D 's logic analyzer the slave select goes low and about 2 clock cycles later it goes Hi.
Short Video of whats going on.
Update: used a smaller sec/dev: slave select is not the problem my code does not transfer data ? new analyzer video
Progress, it seems the uno does not have enough umph (5v) to run three sensors.
results are more promissing with just one. Here is a video and the code as it stands now. Still need help with it,please !!!
/* ******************************************************************************
* SPI read 3x A1335 rotation sensor chips with UNO and display on serial monitor
* Slave select pins 10 >ss1, 9 >ss2, 8 >ss3
*/
#include <SPI.h>
//SPI.setMOSI(11)
//SPI.setMISO(12)
// set slave pins and variables
const int ss1 = 10;
const int ss2 = 9;
const int ss3 = 8;
uint16_t Ang_ss1 = 0;
uint16_t Ang_ss2 = 0;
uint16_t Ang_ss3 = 0;
/*SPI settings here and not declared globaly for attaching different
spi devices with difrent settings. Call transaction,begin with new
settings*/
SPISettings settingsA(10000000,MSBFIRST,SPI_MODE3); //moved into setup ,moved back
void setup() {
/* SPI.setClockDivider (SPI_CLOCK_DIV2);
SPI.setDataMode (SPI_MODE3);
SPI.setBitOrder (MSBFIRST);*/
//set slave pins High and as outputs
pinMode (ss1,OUTPUT);
digitalWrite (ss1,HIGH);
pinMode (ss2,OUTPUT);
digitalWrite (ss2,HIGH);
pinMode (ss3,OUTPUT);
digitalWrite (ss3,HIGH);
//set up register once and receive data in loop
Serial.begin(9600);
SPI.begin();
SPI.beginTransaction(settingsA);
digitalWrite (ss1,LOW);
SPI.transfer(0x20);
SPI.transfer(0);
digitalWrite(ss1,HIGH);
SPI.endTransaction();
}
void loop() {
SPI.beginTransaction(settingsA);
//select sensor 1 to 3 and read registers 0x20 and 0x21
digitalWrite (ss1,LOW); // sensor one read and store two bite data in ANG_ss1
Ang_ss1 = SPI.transfer(0x20); //0x20 and 0x21 angle register
//Ang_ss1 = SPI.transfer(0); // receive data 0x20 high byte
Ang_ss1 = Ang_ss1 <<8;
Ang_ss1 |= SPI.transfer(0);//receive low byte
digitalWrite(ss1,HIGH);
SPI.endTransaction();
//De-bug code: display values from sensors
//Serial.print(Ang_ss1,BIN); //Serial.print Ang_ss1 in binary
Serial.print(Ang_ss1);
Serial.println(" ss1 ");
Ang_ss1 = Ang_ss1 <<4; //first 4 bytes are not part of angle
Ang_ss1 = Ang_ss1 >>4;
Serial.print(Ang_ss1);Serial.println(" ss1 shifted");
//Serial.print(Ang_ss1,BIN);Serial.println(" ss1 shifted"); // Ang_ss1 shifted in binary
Serial.print(Ang_ss1 * 360/4096 ); // formula from programming manual for sensor, removed '(' from (360/4096)
// need help here the formula in manual is n*(360/4096)
Serial.println(" DEG ");
delay (1000); // to read serial monitor for debugging
}
just relised I did not save code for 2 sensors