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I have pull up resistors on the /SSEL pins of the SPI bus. I want to use the LPC2129 as master, let him send 10 bytes .. 1 time Ox55 and 9 times 0x00 but it seems not to work. Is there something wrong with the code?
With a scope I see the P0.0 work well as chip selector but I don't see a clk running also no data on the mosi/miso lines.
Here is my code:
#include <LPC21xx.H> #include "Timer.h" functions unsigned int dummy; unsigned int status = 0x0; unsigned int s = 0x0; unsigned int i = 0x0; unsigned int cnt = 0x0; unsigned int buf[10]; void SPI0_Init(void) { S0SPCCR = 0xFA; S0SPCR = 0x28; IOSET1 = 0x00020000; } int SPI0_WriteAA(void) { S0SPDR = 0x55; while(!(S0SPSR & 0x80)){} if (S0SPSR != 0x80) { IOCLR1 = 0x00400000; IOSET1 = 0x00800000; status = 0x1; } else { IOCLR1 = 0x00800000; IOSET1 = 0x00400000; status = 0x0; } s = S0SPSR; return(status); } int SPI0_WriteFF(void) { S0SPDR = 0x00; while(!(S0SPSR & 0x80)){}; if (S0SPSR != 0x80) { IOCLR1 = 0x00400000; IOSET1 = 0x00800000; status = 0x1; } else { IOCLR1 = 0x00800000; IOSET1 = 0x00400000; status = 0x0; } s = S0SPSR; return(status); } int SPI0_Read(void) { dummy = S0SPDR; //read data register buf[cnt] = dummy; if (cnt < 10) { cnt++; } return(dummy); } void wait (void) { unsigned long i; i = timeval; while ((i + 100) != timeval); } void waitstartup (void) { unsigned long i; i = timeval; while ((i + 15) != timeval); } int main (void) { int c; PINSEL0 = 0x00005500; IODIR0 = 0x00010001; IOCLR0 = 0xFFFFFFFF; IOSET0 = 0x00010001; PINSEL1 = 0x154542A8; IODIR1 = 0x00FF0000; IOCLR1 = 0x00FF0000; IOSET1 = 0x00010000; SPI0_Init(); init_timer(); waitstartup(); IOCLR0 = 0x00000001; IOSET1 = 0x00040000; while (1) { if (i==0) { SPI0_WriteAA(); if (status == 0x0) { SPI0_Read(); } for (c=0;c<9;c++) { SPI0_WriteFF(); if (status == 0x0) { SPI0_Read(); } } i=1; IOSET0 = 0x00000001; wait(); IOCLR1 = 0x00040000; } } }
I did delete the comments here with comments I think it will make some more sense.
;/*******************************************************************************/ ;/* Sensor.c: Reading the angle via the Melexis 90316 using SPI */ ;/* the measured angle will be send out via CAN. */ ;/*******************************************************************************/ #include <LPC21xx.H> // LPC21xx definitions #include <stdio.h> #include "Timer.h" // Timer voor wait functions unsigned int dummy; unsigned int status = 0x0; //0x0 = ok , 0x1 = error unsigned int s = 0x0; unsigned int i = 0x0; unsigned int cnt = 0x0; unsigned int buf[10]; //#define S0SPCR control function SPI interface //#define S0SPSR monitor status SPI interface //#define S0SPDR transmit/received data register //#define S0SPCCR controls clock rate (as master) //#define S0SPINT interupt flag void SPI0_Init(void) { S0SPCCR = 0x3C; /* 8 >, even, SCK=15M/250 = 60k */ S0SPCR = 0x28; /* CPHA=1, CPOL=0, master mode, MSB first, interrupt enabled */ IOSET1 = 0x00020000; /* Blink a led */ } int SPI0_WriteAA(void) { S0SPDR = 0x55; //write data to SPI data register, AA after inv. while(!(S0SPSR & 0x80)){} //wait until SPIF bit is set if (S0SPSR != 0x80) { IOCLR1 = 0x00400000; IOSET1 = 0x00800000; //error indicatie status = 0x1; } else { IOCLR1 = 0x00800000; IOSET1 = 0x00400000; //status = ok status = 0x0; } dummy = S0SPDR; return(status); } int SPI0_WriteFF(void) { S0SPDR = 0x00; //write data to SPI data register, FF after inv. while(!(S0SPSR & 0x80)){}; //wait until SPIF bit is set if (S0SPSR != 0x80) { IOCLR1 = 0x00400000; IOSET1 = 0x00800000; //error indicatie status = 0x1; } else { IOCLR1 = 0x00800000; IOSET1 = 0x00400000; //status = ok status = 0x0; } s = S0SPSR; return(status); } int SPI0_Read(void) { dummy = S0SPDR; //read data register buf[cnt] = dummy; if (cnt < 10) { cnt++; } return(dummy); } void wait (void) { /* wait function */ unsigned long i; i = timeval; while ((i + 100) != timeval); /* wait 100ms */ } void waitstartup (void) { /* wait function */ unsigned long i; i = timeval; while ((i + 15) != timeval); /* wait 5ms */ } int main (void) { int c; PINSEL0 = 0x00005500; /* Pin select */ IODIR0 = 0x00010001; /* Select pin direction */ IOCLR0 = 0xFFFFFFFF; /* GPIO P0.3 and P0.16 as outputs */ IOSET0 = 0x00010001; /* SSEL = '1' */ PINSEL1 = 0x154542A8; IODIR1 = 0x00FF0000; /* Select direction pins */ /* GPIO P1.16 - P1.23 as outputs */ IOCLR1 = 0x00FF0000; /* All leds off */ IOSET1 = 0x00010000; /* Status led, system is running */ SPI0_Init(); init_timer(); waitstartup(); IOCLR0 = 0x00000001; //SSEL = '0' IOSET1 = 0x00040000; //set SSEL led while (1) { IOCLR0 = 0x00000001; //SSEL = '0' SPI0_WriteAA(); if (status == 0x0) { SPI0_Read(); } IOSET0 = 0x00000001; //SSEL = '1' wait(); //extra wait voor LED indicatie IOCLR1 = 0x00040000; //clear SSEL led } }
The missing edit buttons can in some cases be handled by the preview function.
A couple of notes about your comments:
PINSEL0 selects mode for a numbers of P0.x pins, so the comment shouldn't mention "Pin select" but what special configuration you are specifying (such as enabling the SPI pins).
IODIR0 selects I/O direction for a number of pins, so the comment "Select pin direction" doesn't give much extra help. Which pins are set as outputs?
The comment "GPIO P0.3 and P0.16 as outputs" doesn't seem to match the I0DIR0 assign.
If you declare a constant SSEL = 0, you may write
IOSET1 = 1 << SSEL;
Your program performs just about everything using global variables. That doesn't help you a lot. It isn't visible which global variables are updated by which calls, so when reading the code, you can not see if an if statement makes sense or not.
Note how similar SPI0_WriteAA and SPI0_WriteFF are? That may be a good indication that you should just have a SPI0_Write() function, and use a parameter to inform what value to send.
Per Westermark said, "Do you like code with a lot of long "magic" hex constants? It takes significant time to look at them and correlate with the datasheet to see what your intentions are."
Bas van Dijk replied, "I did delete the comments here with comments I think it will make some more sense."
Magic numbers with comments is little more help than "bare" magic numbers!
Much better to use meaningful symbolic names!