<?xml version="1.0" encoding="UTF-8" ?>
<?xml-stylesheet type="text/xsl" href="https://community.arm.com/utility/feedstylesheets/rss.xsl" media="screen"?><rss version="2.0" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:slash="http://purl.org/rss/1.0/modules/slash/" xmlns:wfw="http://wellformedweb.org/CommentAPI/"><channel><title>I can&amp;#39;t write data through USB</title><link>https://community.arm.com/developer/tools-software/tools/f/keil-forum/29881/i-can-t-write-data-through-usb</link><description> 
Hello, 
I&amp;#39;m trying to send data my usb device using simpleHIDWrite tool, but
I&amp;#39;m getting this error: 
access violation at address 00000, read of address 00000 
Does anyone have an idea about what could be the source of this
problem. 
 </description><dc:language>en-US</dc:language><generator>Telligent Community 10</generator><item><title>RE: I can't write data through USB</title><link>https://community.arm.com/thread/145500?ContentTypeID=1</link><pubDate>Mon, 08 Apr 2013 06:58:02 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:c9eb94d8-0142-4584-a9c5-482bb55a4f79</guid><dc:creator>Aounallah Mazen</dc:creator><description>&lt;p&gt;&lt;p&gt;
I&amp;#39;m really grateful for your help sir,&lt;br /&gt;
Every thing is clear, but it is weird that this matter is not
mentioned in the HID spec, or not very highlighted to attract my
attention.&lt;/p&gt;
&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: I can't write data through USB</title><link>https://community.arm.com/thread/143382?ContentTypeID=1</link><pubDate>Mon, 08 Apr 2013 05:53:38 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:2feac4f2-b4f6-4aea-a66b-ae00ba04e3e0</guid><dc:creator>Chinzei Tsuneo</dc:creator><description>&lt;p&gt;&lt;p&gt;
&lt;i&gt;&amp;gt; it seems that I always start by sending a zero even that
the first byte is not defined to be zero.&lt;/i&gt;&lt;/p&gt;

&lt;p&gt;
It&amp;#39;s the Windows way how MS implement PC HID driver.&lt;br /&gt;
When your report descriptor on the device has no report ID, the
default report ID (0) is assumed by the HID spec. On the firmware
side, no report ID is preceded on the reports, exchanged by the
device. But Windows application has to add the report ID: 0 before
every type of reports. This report ID is deleted by the PC HID
driver, when it is sent to the device. Also, this report ID is added
by the HID PC driver, when it comes from the device.&lt;/p&gt;

&lt;p&gt;
Tsuneo&lt;/p&gt;
&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: I can't write data through USB</title><link>https://community.arm.com/thread/140542?ContentTypeID=1</link><pubDate>Mon, 08 Apr 2013 03:23:24 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:cfa378c7-8323-4581-9627-e03c9e628522</guid><dc:creator>Mazen Aounallah</dc:creator><description>&lt;p&gt;&lt;p&gt;
Here is my report descriptor:&lt;/p&gt;

&lt;pre&gt;
0x06, 0x00, 0xff,              // USAGE_PAGE (Vendor Defined Page 1)
    0x09, 0x01,                    // USAGE (Vendor Usage 1)
    0xA1, 0x01,                    // COLLECTION (Application)
    0x15, 0x00,                    //   LOGICAL_MINIMUM (0)
    0x26, 0xff, 0x00,              //   LOGICAL_MAXIMUM (255)
    0x75, 0x08,                    //   REPORT_SIZE (8)
    0x95, 0x40,                    //   REPORT_COUNT (64)
    0x09, 0x01,                    //   USAGE (Vendor Usage 1)
    0x81, 0x02,                    //   INPUT (Data,Var,Abs)
    0x95, 0x40,                    //   REPORT_COUNT (64)
    0x09, 0x01,                    //   USAGE (Vendor Usage 1)
    0x91, 0x02,                    //   OUTPUT (Data,Var,Abs)
    0x95, 0x01,                    //   REPORT_COUNT (1)
    0x09, 0x01,                    //   USAGE (Vendor Usage 1)
    0xB1, 0x02,                    //   FEATURE (Data,Var,Abs)
    0xc0                           // END_COLLECTION
&lt;/pre&gt;
&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: I can't write data through USB</title><link>https://community.arm.com/thread/131240?ContentTypeID=1</link><pubDate>Mon, 08 Apr 2013 02:32:33 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:00ff0758-781f-4d1f-a26b-f5a9b2ea16d9</guid><dc:creator>Aounallah Mazen</dc:creator><description>&lt;p&gt;&lt;p&gt;
Hello,&lt;br /&gt;
I tried the new software, it seems that I always start by sending a
zero even that the first byte is not defined to be zero.&lt;br /&gt;
Do you have any idea about this problem?&lt;/p&gt;
&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: I can't write data through USB</title><link>https://community.arm.com/thread/136992?ContentTypeID=1</link><pubDate>Sun, 07 Apr 2013 05:23:17 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:e4ccfffa-7c45-420a-87ce-835304d543c0</guid><dc:creator>Mazen Aounallah</dc:creator><description>&lt;p&gt;&lt;p&gt;
Thanks for your support Tsuneo,&lt;br /&gt;
I&amp;#39;ll test this on monday.&lt;/p&gt;
&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: I can't write data through USB</title><link>https://community.arm.com/thread/117245?ContentTypeID=1</link><pubDate>Fri, 05 Apr 2013 09:33:31 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:4277c768-faad-4933-86a6-d1209b83f2fb</guid><dc:creator>Mazen Aounallah</dc:creator><description>&lt;p&gt;&lt;p&gt;
I think I know what a null pointer means.&lt;br /&gt;
In fact after more searching on my problem I found that when I make a
report with a report size = 8 and a report count = 64 or more I get
this error but when the report count = 63 There is no error and all
the data are transmitted, The problem is that I&amp;#39;m transmitting 64
byte while I&amp;#39;m declaring the report count to be 63.&lt;br /&gt;
I&amp;#39;m supposing that the first byte sent is the report id so the total
size of the transmitted data is 63+1=64.&lt;br /&gt;
I&amp;#39;m wondering If I can omit the report id and use it as a data
byte.&lt;/p&gt;
&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item><item><title>RE: I can't write data through USB</title><link>https://community.arm.com/thread/107004?ContentTypeID=1</link><pubDate>Fri, 05 Apr 2013 04:58:45 GMT</pubDate><guid isPermaLink="false">dd9e70c8-6d3c-4c71-b136-2456382a7b5c:0a329e8f-a625-406f-9cf4-3c36d3b4afe5</guid><dc:creator>ImPer Westermark</dc:creator><description>&lt;p&gt;&lt;p&gt;
Time to pick up a good introductory level book about C, and read
up on pointers, null pointers and pointer indirection (referencing
the target of the pointer).&lt;/p&gt;
&lt;/p&gt;&lt;div style="clear:both;"&gt;&lt;/div&gt;</description></item></channel></rss>