working serialUSB with timeout

as a temporary workaround for the fact that SerialUSB is often blocking,
this crude implementation makes the low-level C usbSendBytes function
non-blocking (with a return code of bytes sent) and implements a 2ms
timeout in the wirish write() function.

also adds begin(), end(), getDTR(), getRTS(), pending(). device is still
initialized the old fashioned way during init() so that, eg, autoreset
will work. includes a simple multi-test program.

1 files changed, 38 insertions, 5 deletions

diff --git a/wirish/usb_serial.cpp b/wirish/usb_serial.cpp
index f186dea..2effa3d 100644
--- a/wirish/usb_serial.cpp
+++ b/wirish/usb_serial.cpp
@@ -32,24 +32,53 @@
 #include "wirish.h"
 #include "usb.h"
 
+#define USB_TIMEOUT 2
+
 USBSerial :: USBSerial(void) {
 }
 
+void USBSerial::begin(void) {
+    setupUSB();
+}
+
+void USBSerial::end(void) {
+    disableUSB();
+}
+
 void USBSerial::write(uint8 ch) {
-  usbSendBytes(&ch, 1);
+    uint16 status = 0;
+    uint32 start = millis();
+    while(status == 0 && (millis() - start <= USB_TIMEOUT)) {
+        status = usbSendBytes(&ch, 1);
+    }
 }
 
 void USBSerial::write(const char *str) {
-   uint32 len = strlen(str);
- 
-   usbSendBytes((uint8*)str, len);
+    uint32 len = strlen(str);
+    uint16 status = 0;
+    uint16 oldstatus = 0;
+    uint32 start = millis();
+    while(status < len && (millis() - start < USB_TIMEOUT)) {
+        status += usbSendBytes((uint8*)str+status, len-status);
+        if(oldstatus != status) 
+            start = millis();
+        oldstatus = status;
+    }
 }
 
 void USBSerial::write(void *buf, uint32 size) {
    if (!buf) {
       return;
    }
-   usbSendBytes((uint8*)buf, size);
+    uint16 status = 0;
+    uint16 oldstatus = 0;
+    uint32 start = millis();
+    while(status < size && (millis() - start < USB_TIMEOUT)) {
+        status += usbSendBytes((uint8*)buf+status, size-status);
+        if(oldstatus != status) 
+            start = millis();
+        oldstatus = status;
+    }
 }
 
 uint32 USBSerial::available(void) {
@@ -70,5 +99,9 @@ uint8 USBSerial::read(void) {
    return ch;
 }
 
+uint8 USBSerial::pending(void) {
+   return usbGetPending();
+}
+
 USBSerial SerialUSB;