i am currently using lpc2468 usbhostlite code and getting the required results. can anyone please help me make the necessary changes in the code to use it with fat32 formatted pendrives also
Is the buffer passed to FILE_Write() / FILE_Read() placed on the USB RAM (HOST_BASE_ADDR)?
This buffer is directly put into the Transfer Descriptor for DMA by the host controller. It means the buffer should be placed on the USB RAM. LPC23xx/24xx families have this restriction on DMA by USB controller.
In the USB host lite example, it manages buffer assignment as follows.
usbhost_lpc2468.c volatile HCED *EDCtrl; /* Control endpoint descriptor structure */ volatile HCED *EDBulkIn; /* BulkIn endpoint descriptor structure */ volatile HCED *EDBulkOut; /* BulkOut endpoint descriptor structure */ volatile HCTD *TDHead; /* Head transfer descriptor structure */ volatile HCTD *TDTail; /* Tail transfer descriptor structure */ volatile HCCA *Hcca; /* Host Controller Communications Area structure */ USB_INT16U *TDBufNonVol; /* Identical to TDBuffer just to reduce compiler warnings */ volatile USB_INT08U *TDBuffer; /* Current Buffer Pointer of transfer descriptor */ volatile USB_INT08U *FATBuffer; /* Buffer used by FAT file system */ volatile USB_INT08U *UserBuffer; /* Buffer used by application */ void Host_Init (void) { ... Hcca = (volatile HCCA *)(HOST_BASE_ADDR+0x000); TDHead = (volatile HCTD *)(HOST_BASE_ADDR+0x100); TDTail = (volatile HCTD *)(HOST_BASE_ADDR+0x110); EDCtrl = (volatile HCED *)(HOST_BASE_ADDR+0x120); EDBulkIn = (volatile HCED *)(HOST_BASE_ADDR+0x130); EDBulkOut = (volatile HCED *)(HOST_BASE_ADDR+0x140); TDBuffer = (volatile USB_INT08U *)(HOST_BASE_ADDR+0x150); FATBuffer = (volatile USB_INT08U *)(HOST_BASE_ADDR+0x1D0); UserBuffer = (volatile USB_INT08U *)(HOST_BASE_ADDR+0x1000);
If the buffer would be placed on the USB RAM, you don't need abuve repeated FILE_Write(). Single FILE_Write() call with whole buffer will do.
Tsuneo
Thanks Sir
No, Sir buffer was not placed on USB RAM.
Thank You so much Sir you solved my problem
you are genuinely a master.