| View previous topic :: View next topic |
| Author |
Message |
dsaari
Joined: 05 May 2006
Posts: 25
|
| Optical Mouse Chip |
 Posted: Sat Apr 11, 2009 10:29 am |
 |
|
I'm trying interface a PIC16F876 @20MHz to a ADSN-2610 optical mouse sensor. I just want to spit out the positional information to my debug screen for now. The question I have is setting up for the SPI communication on this sensor. It uses half duplex so SDI and SDO are coming from the same pin on the sensor. I think I would just need to tie the SDI & SDO together on the pic, but I'm not certain.
The data sheet for the ADSN-26XX is here:
http://www.avagotech.com/docs/AV02-1184EN
Additionally, I am trying to figure out how to configure the SPI port to talk to this thing software wise. I am just finishing up the hardware interface now. I think I have it working because the LED turns on brighter when I bump the board, so I know it's doing it's thing, now I've just got to talk to it.
Any help would be appreciated.
Thanks! |
|
 |
dsaari
Joined: 05 May 2006
Posts: 25
|
| Optical Mouse Sensor |
| Posted: Sat Apr 11, 2009 5:21 pm |
|
|
Ok,
I think I've got thinks talking a bit. I can send configuration data to the chip to take it out of power savings mode. I know this is working because the LED goes from dim to bright when I send the configuration data. I went and connected the SDI and SDO pins together. I still can't read any data though. The code below will make the LED shine bright (take it out of power saving mode) but I'm not getting anything on the read.
| Code: | #include <16F876.h> //PIC microcontroller driver
#DEVICE CCSICD=TRUE //Use the ICD debugger
#fuses NOWDT, HS, NOPUT, NOPROTECT, NOBROWNOUT, NOLVP, NOCPD, NOWRT//, DEBUG
#use delay(clock=20000000) //20MHz clock
#use rs232(debugger)
//****************************************************************************//
#define BUTTON PIN_A5 // Chip button pin
#define LED PIN_A0 // Chip LED pin
#define CONFIG 0x80
#define STATUS 0x01
#define DELTAY 0x02
#define DELTAX 0x03
#define SQUAL 0x04
#define INIT 0x01
int8 FRANK = 0;
//****************************************************************************//
//**********************************MAIN**************************************//
void main()
{
setup_adc_ports(NO_ANALOGS); //Make these I/O pins A/D inputs
setup_adc(ADC_OFF); //MAke the A/D clock an internal reference
setup_spi(SPI_MASTER | SPI_XMIT_L_TO_H | SPI_CLK_DIV_16); //setup SPI mode
setup_timer_1(T1_DISABLED); //Disable timer1
setup_timer_2(T2_DISABLED,0,1);//Disable timer2
printf("\n\r"); //Print out the following to the USART
printf("\n\r");
printf("MARVEL MOUSE\n\r");
printf("***********************************\n\r");
delay_ms(200);
spi_write(CONFIG);
spi_write(INIT);
while (TRUE) //Main loop
{
if (!input(BUTTON))
{
output_high(LED);
}
else output_low(LED);
delay_ms(20);
spi_write(DELTAX);
delay_ms(10);
FRANK = spi_read();
printf("FRANK = %d\n\r", FRANK);
}
} |
Any thoughts? |
|
|
PCM programmer
Joined: 06 Sep 2003
Posts: 21708
|
|
| Posted: Sat Apr 11, 2009 6:56 pm |
|
|
spi_read() must have a parameter if want to get a clock signal out of
the SCLK pin. This is in the manual. Normally it's done with a 0
parameter. Example:
| Code: | | result = spi_read(0); |
|
|
|
dsaari
Joined: 05 May 2006
Posts: 25
|
| Optical Mouse Sensor |
| Posted: Sat Apr 11, 2009 11:12 pm |
|
|
Alright, I tried your recommendation but am still having troubles. I know that I am able to write to the sensor because I can get it to react as I'd expect using power down and reset configurations. I really do feel that it is responding correctly to spi_writes. When I go to read however, I don't get anything back. If I leave the read_spi() blank, FRANK printf's "3". If I put read_spi(0) then FRANK printf's "0". So your recommendation had an effect but It's still not changing when I move the sensor. Any further thoughts or hints?
Thank you. |
|
|
PCM programmer
Joined: 06 Sep 2003
Posts: 21708
|
|
| Posted: Sat Apr 11, 2009 11:36 pm |
|
|
My advice is to start with the CCS ds1302 driver and use it as a base
to build your Optical mouse chip driver. The DS1302 is a 3-wire chip.
The CCS driver uses software SPI to talk to the chip. I think you can
modify the DS1302 driver fairly quickly to work with the Avago chip.
| Quote: | | c:\program files\picc\drivers\ds1302.c |
|
|
|
asmallri
Joined: 12 Aug 2004
Posts: 1635
Location: Perth, Australia
|
| Re: Optical Mouse Sensor |
| Posted: Sun Apr 12, 2009 4:47 am |
|
|
| dsaari wrote: | Alright, I tried your recommendation but am still having troubles. I know that I am able to write to the sensor because I can get it to react as I'd expect using power down and reset configurations. I really do feel that it is responding correctly to spi_writes. When I go to read however, I don't get anything back. If I leave the read_spi() blank, FRANK printf's "3". If I put read_spi(0) then FRANK printf's "0". So your recommendation had an effect but It's still not changing when I move the sensor. Any further thoughts or hints?
Thank you. |
This is because the SPI and SPO are tied together. Whatever is written on SPO will appear on SPI. The solution is to put a 1K series resistor in the SDO output from the PIC.
So the schematic has the PIC SPI connected directly to the sensor and the PIC SDO is connected via the series resistor to SPI.
_________________
Regards, Andrew
http://www.brushelectronics.com/software
Home of Ethernet, SD card and Encrypted Serial Bootloaders for PICs!! |
|
|
dsaari
Joined: 05 May 2006
Posts: 25
|
| Optical Mouse Sensor |
| Posted: Sun Apr 12, 2009 6:23 am |
|
|
| Thank you asmallri! I added the 1kohm and now I got data. I don't know what it means yet but I've got it. When I move, the numbers seem to increase and decrease depending on direction. I get zeros if I stop, but I think the register clears itself when I read it. Again thank you! |
|
|
Franck26
Joined: 29 Dec 2007
Posts: 122
Location: Ireland
|
|
| Posted: Sun Apr 12, 2009 1:27 pm |
|
|
Hi Dsaari,
I suppose that what you read is the difference of position since the last reading.
It would explain why you've got 0 when you don't move.
To know the position at each time, you have to add the value of each of readings.
Good luck,
Franck. |
|
|
|
FAQ 
Search
Register
Profile 
Log in to check your private messages 
Log in
