[ts-7000] Odd results Polling DIO on 7800

["eric.robishaw" <>]

Attempting to poll the DIO lines on 7800.
(I've modified the button example to use as a base for polling the DIO lines.)

CODE BELOW

However, there are some strange issues I can't figure out.

1. If I short pins 2 (ground*) to the odd numbered pins (HI via 2.2K) I expect value changes on the DIO line, but only get changes in pins:
   1, 3 & 5
2. If I short pins 16 (3.3V) to even pins (except pin 10), I only get value changes on:
   4 AND 8
3. I can't make heads or tails of the return values.
   For example:
   
   No pins shorted = 0x15
   

> Pin 1 =0x14,
> Pin 3 = 0x11,
> Both 1 & 3 = 0x10
>
> How is 0x10 derived from 0x14 AND 0x11?
> In binary:
> 0x11: 0001 0001
> 0x14:0001 0100
> 0x10:00010000
>
> It's obviously not ored, anded or Xored.
The Bottom line que
 stion is this:
How do I determine which pins are shorted from the value of state (see code)
Why do I not get state changes from pins 6,7,9-15



BEWARE: the 7800 manual is incorrect.  According to the specs,
pin 2 is Ground (not an input/output) and pin 16 is 3.3V (again, not an
IO line)

CODE: 

#define DIOBASE 0xE8000000
int main(int argc, char **argv)
{
    volatile unsigned int *PBDR, *PBDDR, *GPIOBDB;
    
    int i;
    unsigned char state;
    unsigned char *start;
    int fd = open("/dev/mem", O_RDWR);
    
    start = mmap(0, getpagesize(), PROT_READ|PROT_WRITE, MAP_SHARED, fd, DIOBASE);    
    
    PBDR = (unsigned int *)(start + 0x04); //port b            //starting address of DIO read, E8000000 + 4 = E80000004
    PBDDR = (unsigned int *)(start + 0x14); //port b direction
    
    GPIOBDB = (unsigned int *)(start + 0xC4); // debounce on port b
&
 nbsp;   
    *PBDDR = 0xf0; //upper nibble output, lower nibble input
    *GPIOBDB = 0x01; //enable debounce on bit 0
    state = *PBDR; // read initial state
    
    printf ("Press buttons on DIO inputs. Ctrl-C to Quit.\n");

    int count = 0;
    unsigned char oldstate = (unsigned char)0;
    while (1) //(state & 0x01)
    {
        state = *PBDR; // remember bit 0 is pulled up with 4.7k ohm
        if (oldstate != state)
        {
            printf ("State:%x\n", state);
            oldstate = state;
        }
        usleep(100);
&nb
 s
 p;       count++;
    }
    printf ("\nDONE\n");
    close(fd);
    return 0;
}


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