According to the EP9301 user manual, i have written a sample code to
read a voltage level on the GPI0 pin4 which is portC bit0. Once the
code is running, i cant get a accurate result. Let say i set the input
voltage to 1V but on the terminal the displayed voltage level keep
varying.
Maybe i missed something that must set in the registers.
I have read the sample code provided from Embededarm website. But I
cant understand it. It seem like I must correct the ADCResult with the
caribration value stored inside the EEPROM.
Anyone please help?
Just for your info my board is based on the EP9302-CQ cirrus arm
processor. Is the register addresses inside the EP9301 user munual
valid for EP9302?
Below shows the code that i have written.
--------------------------------------------------------------------
#include<sys/types.h>
#include<sys/mman.h>
#include<stdio.h>
#include<fcntl.h>
#include<string.h>
main(int argc, char **argv)
{
volatile unsigned int *SysSWLock, *ADCClkDiv, *DevCfg, *ADCSWLock,
*ADCResult, *ADCSwitch, *PBDDR, *PBDR, *GPIOBDB;
unsigned char *SysconBase, *ADCBase, *start;
float ADResult;
unsigned char state;
int fd = open("/dev/mem", O_RDWR);
SysconBase = mmap(0, getpagesize(), PROT_READ|PROT_WRITE, MAP_SHARED,
fd, 0x80930000);
ADCBase = mmap(0, getpagesize(), PROT_READ|PROT_WRITE, MAP_SHARED, fd,
0x80900000);
start = mmap(0, getpagesize(), PROT_READ|PROT_WRITE, MAP_SHARED, fd,
0x80840000);
/*Assign register addresses to pointers according to ep9301 user guide*/
SysSWLock = (unsigned int *)(SysconBase + 0xC0);
ADCClkDiv = (unsigned int *)(SysconBase + 0x90);
DevCfg = (unsigned int *)(SysconBase + 0x80);
ADCSWLock = (unsigned int *)(ADCBase + 0x20);
ADCResult = (unsigned int *)(ADCBase + 0x08);
ADCSwitch = (unsigned int *)(ADCBase + 0x18);
PBDDR = (unsigned int *)(start + 0x14); //port b direction
PBDR = (unsigned int *)(start + 0x04); //port b
GPIOBDB = (unsigned int *)(start + 0xC4); // debounce on port b
/*Setup the PortB to received digital input*/
*PBDDR = 0xf0; //upper nibble output, lower nibble input
*GPIOBDB = 0x01; //enable debounce on bit 0
/*Steps to setup the onboard ADC for ts-7200*/
*SysSWLock = 0xAA; //unlock the software lock for the all registers
*ADCClkDiv |= 0x80010000; //enable TSEN(bit32)-AD clock start, enable
ADIV(bit16)-AD clk/4
*SysSWLock = 0xAA; //unlock the software lock for the all registers
(AGAIN)
*DevCfg |= 0x00020000; //Set the ADCEN - ADC enable.
*SysSWLock = 0xAA; //unlock the software lock for the all registers
(AGAIN)
*DevCfg &= 0xFFFFFFFB; //Clear the ADCPD-ADC. Set 1 to Power Down
*ADCSWLock = 0xAA; //unlock the software lock for the all registers
(AGAIN)
*ADCSwitch = 0x00000608; //Enable AD channel 4 to receive analog signal.
/*do while loop is terminated when portb bit0 is "0". Default pull up
to logic "1"*/
do
{
state = *PBDR;
while((*ADCResult & 0x80000000)==0x80000000); //pooling until
bit31 set then exit.
ADResult = ((float)(*ADCResult & 0x00000FFF)/4095)*3;
printf("Channel 0 Result: %f \n", ADResult);
}while(state & 0x01);
close(fd);
return 0;
}
Yahoo! Groups Links
<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/ts-7000/
<*> Your email settings:
Individual Email | Traditional
<*> To change settings online go to:
http://groups.yahoo.com/group/ts-7000/join
(Yahoo! ID required)
<*> To change settings via email:
<*> To unsubscribe from this group, send an email to:
<*> Your use of Yahoo! Groups is subject to:
http://docs.yahoo.com/info/terms/
|