L0100: MOV DPTR,#L7FE9
MOVX A,@DPTR
JNZ L0109
LJMP L029B ;if bRequest = GetStatus jump to 0x029B
L0109: DEC A
JNZ L010F
LJMP L0317 ;if bRequest = Clear Feature, jump to 0x0317
L010F: ADD A,#0FEh
JNZ L0116
LJMP L038E ;if bRequest = Set Feature, jump to 0x038E
L0116: ADD A,#0FBh
JNZ L011D
LJMP L0295 ;if bRequest = Get Configuration, jump to 0x0295
L011D: DEC A
JNZ L0123
LJMP L028F ;if bRequest = Set Configuration, jump to 0x028F
L0123: DEC A
JNZ L0129
LJMP L0283 ;if bRequest = Get Interface, jump to 0x0283
L0129: DEC A
JNZ L012F
LJMP L0289 ;if bRequest = Set Interface, jump to 0x0289
L012F: ADD A,#05h
JZ L0136
LJMP L03E2 ;if bRequest = none of the above, then set bits HSNAK
;and EP0STALL of EP0CS control & status register and
;then RET at 0x05FD
;
L0136: LCALL L0F7A ;if bRequest = Get Descriptor, LCALL 0x0F7A where
JC L013E ;carry bit is set by default, so jump to 0x013E
LJMP L03EE ;if at 0x0F7A carry would be 0 by default, set bit HSNAK
;of EP0CS control & status register and RET at 0x05FD
;
L013E: MOV DPTR,#L7FEB ;here because bRequest was a Get Descriptor
MOVX A,@DPTR ;thus, check the WValueH field of USB SETUP packet
ADD A,#0FEh
JZ L015F ;if wValueH was 0x02 jump to 0x015F
DEC A
JZ L0190 ;if wValueH was 0x03 jump to 0x0190
ADD A,#02h
JZ L0150 ;if wValueH was 0x01 jump to 0x0150
LJMP L0279 ;if wValueh is different of either 0x01 or 0x02 or 0x03 then set
;bits HSNAK and EP0STALL of EP0CS register and RET at 0x05FD
;
L0150: MOV A,0Ch ;here because wValueH was 0x01, so load SUDPTR global USB register
MOV DPTR,#L7FD4 ;with value 0x0C0D, then set bit HSNAK of EP0CS and RET at 0x05FD
MOVX @DPTR,A
MOV A,0Dh
MOV DPTR,#L7FD5
MOVX @DPTR,A
LJMP L03EE
L015F: MOV DPTR,#L7FEA ;look now at wValueL field of USB SETUP packet
;
;
;
;
;and so on...................