usbcom: modified libusb example

2 files changed, 197 insertions, 0 deletions

diff --git a/sw/usbcom/Makefile b/sw/usbcom/Makefile
new file mode 100644
index 0000000..e496736
--- /dev/null
+++ b/sw/usbcom/Makefile
@@ -0,0 +1,9 @@
+CC = tcc
+CFLAGS = -std=c99 -Wall
+LDFLAGS = -lusb-1.0
+
+usbcom: usbcom.c
+	$(CC) $(CFLAGS) $(LDFLAGS) -o $@ $^
+
+clean:
+	rm usbcom
diff --git a/sw/usbcom/usbcom.c b/sw/usbcom/usbcom.c
new file mode 100644
index 0000000..55ee395
--- /dev/null
+++ b/sw/usbcom/usbcom.c
@@ -0,0 +1,188 @@
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <libusb-1.0/libusb.h>
+
+#define VENDOR_ID 0x04d8
+#define PRODUCT_ID 0x000a
+
+#define ACM_CTRL_DTR 0x01
+#define ACM_CTRL_RTS 0x02
+
+#define TIMEOUT 1000
+
+#define BUF_SIZE 64
+
+// line encoding: 9600 8N1
+// 9600 = 0x2580 LE
+static unsigned char encoding[] = {0x80, 0x25, 0x00, 0x00, 0x00, 0x00, 0x08};
+
+static struct libusb_device_handle *devh = NULL;
+
+static int ep_in_addr = 0x82;
+static int ep_out_addr = 0x02;
+
+// Returns 0 on success
+static int
+setup(void) {
+	int res;
+
+	res = libusb_init(NULL);
+	if (res < 0) {
+		fprintf(stderr, "Error initializing libusb: %s\n", libusb_error_name(res));
+		return -1;
+	}
+
+	libusb_set_debug(NULL, 3);
+
+	devh = libusb_open_device_with_vid_pid(NULL, VENDOR_ID, PRODUCT_ID);
+	if (!devh) {
+		fprintf(stderr, "Error finding USB device\n");
+		return -1;
+	}
+
+	for (int ifNum = 0; ifNum < 2; ifNum++) {
+		if (libusb_kernel_driver_active(devh, ifNum)) {
+			libusb_detach_kernel_driver(devh, ifNum);
+		}
+		res = libusb_claim_interface(devh, ifNum);
+		if (res < 0) {
+			fprintf(stderr, "error claiming interface: %s\n", libusb_error_name(res));
+			return -1;
+		}
+	}
+
+	res = libusb_control_transfer(devh, 0x21, 0x22, ACM_CTRL_DTR | ACM_CTRL_RTS, 0, NULL, 0, 0);
+	if (res < 0) {
+		fprintf(stderr, "Error during control transfer: %s\n", libusb_error_name(res));
+		return -1;
+	}
+
+	res = libusb_control_transfer(devh, 0x21, 0x20, 0, 0, encoding, sizeof(encoding), 0);
+	if (res < 0) {
+		fprintf(stderr, "Error during control transfer: %s\n", libusb_error_name(res));
+		return -1;
+	}
+
+	return 0;
+}
+
+static void
+teardown(void) {
+	if (devh) {
+		libusb_close(devh);
+	}
+	libusb_exit(NULL);
+}
+
+// Send bytes to USB
+static void
+txChars(unsigned char *data, int n) {
+	int actualLen, res;
+
+	actualLen = 0;
+	while (actualLen < n) {
+		res = libusb_bulk_transfer(devh, ep_out_addr, data, n, &actualLen, TIMEOUT);
+		if (res == LIBUSB_ERROR_TIMEOUT) {
+			printf("Timeout (%d)\n", actualLen);
+		} else if (res < 0) {
+			fprintf(stderr, "Error sending data\n");
+		}
+		assert(actualLen <= n);
+		n -= actualLen;
+		data += actualLen;
+	}
+}
+
+// Read data from USB
+// Returns number of bytes read, or -1 on error
+static int
+rxChars(unsigned char *data, int size) {
+	int res, actualLen;
+
+	res = libusb_bulk_transfer(devh, ep_in_addr, data, size, &actualLen, TIMEOUT);
+	if (res == LIBUSB_ERROR_TIMEOUT) {
+		fprintf(stderr, "Timeout\n");
+		return -1;
+	} else if (res < 0) {
+		fprintf(stderr, "Error receiving data\n");
+		return -1;
+	}
+	return actualLen;
+}
+
+// Get line from stdin
+// Includes '\n'
+// Returns number of chars prior to NUL, or EOF on end of file or error
+static int
+scanline(char *buf, size_t size) {
+	int c, n;
+
+	c = '\0';
+	n = 0;
+	while (n+1 < size) {
+		c = getchar();
+		if (c == EOF) {
+			break;
+		}
+		buf[n++] = c;
+		if (c == '\n') {
+			break;
+		}
+	}
+
+	if (size > 0) {
+		buf[n] = '\0';
+	}
+
+	return ((c == EOF) && (n < 1)) ? EOF : n;
+}
+
+static void
+sendCommand(void) {
+	unsigned char buf[BUF_SIZE];
+	int len;
+
+	while ((len = scanline(buf, sizeof(buf))) != EOF) {
+		txChars(buf, len);
+		if (len > 0 && buf[len-1] == '\n') {
+			break;
+		}
+	}
+}
+
+static void
+printResponse(void) {
+	unsigned char buf[BUF_SIZE];
+	int len;
+
+	while ((len = rxChars(buf, sizeof(buf)-1)) >= 0) {
+		buf[len] = '\0';
+		printf("%s", buf);
+		if (buf[len] == '\n') {
+			return;
+		}
+	}
+}
+
+int
+main(int argc, char *argv[]) {
+	int res;
+	if ((res = setup()) != 0) {
+		teardown();
+		return res;
+	}
+
+	for (;;) {
+		sendCommand();
+		printResponse();
+	}
+
+	libusb_release_interface(devh, 0);
+
+	teardown();
+	return 0;
+}