RE: [usb] Usb1.1: Minor inconsistent behaviour

["Marc Reinig" <mreinig@pacbell.net>]

Setting configuration:

Make sure that wIndex, wLength and wValue (upper byte) for SetConfiguration
are 0.


Strings.

String Index 0 _is_ the Array of Language ID's (9.6.5, USB 1.1 Spec).  The
first string index that contained a string would be Index 1.

The strings themselves are Non null terminated Unicode (not ascii) strings.

Without knowing the specifics of your device, I'm not sure I am reading this
correctly, but...


> `define	ROM_SIZE0	7'd018	// Device Descriptor Length
	This is correct.  The length of the Device Descriptor is 18

> `define	ROM_SIZE1	7'd032	// Configuration Descriptor Length
	The length of a configuration descriptor is 9.  There is also Total Length
which includes the configuration, interface and endpoint descriptors.  For
the device you described, that would be 9 + 9 + 6 + 6 = 30.  So, I'm
confused by the 32.

> `define	ROM_SIZE2A	7'd004	// Language ID Descriptor
	Don't know what this is

> Start Length
> `define	ROM_SIZE2B	7'd010	// String Descriptor Length
	Depends on the string

...

> section from usb1_rom.v:
>
> 		// ====================================
> 		// ===== String Descriptor Lang ID=====
> 		// ====================================
>
> 	   7'h32:	dout <= #1 8'd04;	// this descriptor
>                                   // length IT SHOULD READ
> 						// THE LANG IDS STARTING HERE
> 	   7'h33:	dout <= #1 8'd03;	// descriptor type
> 	   7'h34:	dout <= #1 8'd09;	// Language ID 0 low byte
> 	   7'h35:	dout <= #1 8'd04;	// Language ID 0 high byte
	This seems correct.  Only one language is supported, English.

> 		// ====================================
> 		// =====   String Descriptor 0    =====
> 		// ====================================
	The Language ID is String Descritptor 0.  This should be string descriptor
1

> 	   7'h36:	dout <= #1 8'd020;	// this descriptor length
	Are you saying the length is 20?  Looks like 10 to me.

> 	   7'h37:	dout <= #1 8'd03;	// descriptor type
	This is a string descriptor, that is correct.
	The string below should be Unicode.  Do the values below somehow get
translated to unicode somewhere?  If they do, the string descriptor length
should be 18, not 20.
> 	   7'h38:	dout <= #1 "0";
> 	   7'h39:	dout <= #1 " ";
> 	   7'h3a:	dout <= #1 "g";
> 	   7'h3b:	dout <= #1 "n";
> 	   7'h3c:	dout <= #1 "i";
> 	   7'h3d:	dout <= #1 8'd04;
> 	   7'h3e:	dout <= #1 8'd03;
> 	   7'h3f:	dout <= #1 8'd09;
	Don't understand the last three entries.

> 		// ====================================
> 		// =====   String Descriptor 1    =====
> 		// ====================================
>
> 	   7'h40:	dout <= #1 8'd04;	// this descriptor length
	This string looks longer than 4.
	Similar comments to the previous string apply here.

> 	   7'h41:	dout <= #1 8'd03;	// descriptor type
> 	   7'h42:	dout <= #1 "1";
> 	   7'h43:	dout <= #1 " ";
> 	   7'h44:	dout <= #1 "g";
> 	   7'h45:	dout <= #1 "n";
> 	   7'h46:	dout <= #1 "i";
> 	   7'h47:	dout <= #1 8'd04; // BUT IT ACTUALLY READS
> THE LANGUAGE ID
> TABLE STARTING HERE
> 	   7'h48:	dout <= #1 8'd03;
> 	   7'h49:	dout <= #1 8'd09;

Marc Reinig
System Solutions


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