toggle_led.c

来自「universeII驱动」· C语言 代码 · 共 71 行

#include <vme/vme.h>
#include <vme/vme_api.h>
#include <stdio.h>

#define VME_ADDRESS       0x08000000
#define ADDRESS_MODIFIER  VME_A32SD
#define NBYTES            0x40

int main()
{
	vme_bus_handle_t bus_handle;
	vme_master_handle_t window_handle;
	uint8_t *ptr;
	uint8_t *csr;		/* The CSR register controls the LED */
	const int offset = 0x5;	/* The CSR register is offset 5 bytes from
				   VME_ADDRESS */
	const int bit = 7;	/* Bit 7 controls the LED */

	if (vme_init(&bus_handle)) {
		perror("Error initializing the VMEbus");
		return -1;
	}

	if (vme_master_window_create(bus_handle, &window_handle,
				     VME_ADDRESS, ADDRESS_MODIFIER, NBYTES,
				     VME_CTL_PWEN, NULL)) {
		perror("Error creating the window");
		vme_term(bus_handle);
		return -1;
	}

	ptr = vme_master_window_map(bus_handle, window_handle, 0);
	if (!ptr) {
		perror("Error mapping the window");
		vme_master_window_release(bus_handle, window_handle);
		vme_term(bus_handle);
		return -1;
	}

	/* Toggle the LED */
	csr = ptr + offset;
	if (*csr & (1 << bit)) {
		*csr &= ~(1 << bit);
		printf("The LED should now be off\n");
	} else {
		*csr |= (1 << bit);
		printf("The LED should now be on\n");
	}

	if (vme_master_window_unmap(bus_handle, window_handle)) {
		perror("Error unmapping the window");
		vme_master_window_release(bus_handle, window_handle);
		vme_term(bus_handle);
		return -1;
	}

	if (vme_master_window_release(bus_handle, window_handle)) {
		perror("Error releasing the window");
		vme_term(bus_handle);
		return -1;
	}

	if (vme_term(bus_handle)) {
		perror("Error terminating");
		return -1;
	}

	return 0;
}