Jake Vickers wrote:
> Hello everyone. I just joined the mailing list, and I'm looking for help
> on a specific problem.
> The Wrap.2c board has 1 serial, which is normally used for console
> output (as you know). But it has a LPC connector on board that I was
> under the impression could be configured to add another serial port to
> the board. Has anyone had any experience with this? I'm mainly looking
> to turn a couple pins hi/low to turn on some relays and I contacted the
> support people over at PCEngines, but his reply is over my head (it
> didn't make sense to me). Here's his reply:
<snip>
> Does that make sense to anyone? Ideally I'd like to have a second serial
> port on this board, but if I can just turn the above pins on/off in C
> code that would be fine as well.
> Thanks for taking the time to read this!
I have used the LPC for an interface which I built (I have previously
promised to put the details onto the Voyage Wiki, and will eventually do
that). Attached is the program which I use to "enable" the LPC for
simple I/O on the 6 available bits. There are lots of comments to show
what (I think) I am doing. Once the port is "enabled", you can access it
with straight C port-IO (e.g. 'inl' and 'outl' to the GPIO reg port at
0xf410).
Hope it might help.
Regards,
Bill
/*
* Note: See Page 50 of the SC1100 datasheet for PMR register info
* and Page 196 for GPIO information
*/
#include <sys/io.h>
#include <stdio.h>
#include <unistd.h>
#define GPIO_REGS 0xf400
int main(int nargs, char **argv) {
unsigned int val;
/*
* The main requirement is to clear Bit14 in order to change
* from the LPC config onto a straight GPIO config. Other bits
* are specified as "must be 0", so we clear them as well.
* Bits 31-30, 26, 24-22, 20 and 15 should be written as '0';
* Clear bit 14 disable the LPC, to use GPIO pins on the header
* Remaining bits unchanged.
* 0011 1010 0010 1111 0011 1111 1111 1111
*/
unsigned int mask = 0x3a2f3fff;
/* bit_ids is the GPIO bit number */
unsigned char bit_ids[] = { 32, 33, 34, 35, 36, 37 };
/* Bits 6-4 are only for PME's, which we aren't using (so they don't
* matter). Bit 3 *must* be kept 0, so the only important ones are
* bits 2-1-0. We use the internal pull-ups for both the output pins
* and the input pins. Output must be enabled for all (otherwise we
* can't disable the pull-ups on the inputs).
*
* bit_cfg b6 1=> debounce
* b5 0=> low level / falling edge
* b4 0=> edge trigger
* b3 0=> no lock
* b2 1=> internal pull-up (if b1:0 == 01)
* b1 0=> open drain
* b0 1=> output enabled
*/
unsigned char bit_cfg[] = { 0x45, 0x45, 0x45, 0x45, 0x45, 0x45 };
int ix;
iopl(3); /* Give us lots of privilege */
val = inl(0x9030); /* Fetch the PMR (32-bit fetch) */
fprintf(stderr, "PMR register was %08x, setting it to %08x\n",
val, val & mask);
val = val & mask; /* Clear bits 31-24, 16, 14 */
outl(val, 0x9030); /* Write out the changed value */
val = inl(0x9030);
fprintf(stderr, "PMR register now %08x\n", val);
/* Now set the GPIO configuration for our desired bits */
val = inl(GPIO_REGS+0x18); /* read existing interrupt enable bits
*/
fprintf(stderr, "GPIO Int Enable1 was %08x, clearing our bits\n", val);
val &= 0xffc0; /* clear 37-32 */
outl(val, GPIO_REGS+0x18);
for (ix = 0; ix < sizeof(bit_ids); ix++) {
fprintf(stderr, "Writing %08x to 0x20\n",
(unsigned)bit_ids[ix]);
outl((unsigned)bit_ids[ix], GPIO_REGS+0x20);
fprintf(stderr, "Writing %08x to 0x24\n",
(unsigned)bit_cfg[ix]);
outl((unsigned)bit_cfg[ix], GPIO_REGS+0x24);
}
/* For the input pins, we need to write a '1'. This will
* assure that the pins are not driven low. Since the pull-ups
* are active, with no input there should be a HI, and if the
* input is forced LO we will be able to sense it.
*
* For the output pins, we will also initialize all of the ports
* to a HI (which should be what was previously present when the
* port was configured as LPC).
*/
val = inl(GPIO_REGS+0x10) | 0x3f;
outl(val, GPIO_REGS+0x10);
fprintf(stderr, "All done\n");
return 0;
}_______________________________________________
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