PKP
VS1000 P
ROGRAMMER
’
S
G
UIDE
VSMPG
20.2.3
USB_STATUS - USB Device Status 0xC082
USB_STATUS bits
Name
Bits
Description
USB_STF_BUS_RESET
15
Bus reset occurred
USB_STF_SOF
14
Start-of-frame
USB_STF_RX
13
Receive data
USB_STF_TX_READY
12
Transmitter holding register empty
USB_STF_TX_EMPTY
11
Transmitter empty (idle)
USB_STF_NAK
10
NAK packet sent to host
USB_STF_SETUP
7
Setup packet received
USB_STM_LAST_EP
3:0
Endpoint number of last rx/tx transaction
The USB_STM_LAST_EP can be used mainly for debugging purposes, final software
should be able to work without it.
20.2.4
USB_RDPTR - Receive buffer read pointer 0xC083
USB_RDPTR bits
Name
Bits
Description
USB_RDPTR
15:0
Packet Read Pointer
This buffer marks the index position of the last word that the DSP has successfully read
from the receive packet buffer. DSP should control this register and update the position
after each packet it has read from the receive buffer. After reset this register is zero.
20.2.5
USB_WRPTR - Receive buffer write pointer 0xC084
USB_WRPTR bits
Name
Bits
Description
USB_WRPTR
15:0
Packet Write Pointer
After a packet has been received from the PC, the USB hardware updates this pointer to
the receive buffer memory. USB_WRPTR is index location of the next free word location
in the USB receive buffer. When USB_RDPTR equals to USB_WRPTR, the packet input
buffer is empty. After reset this register is zero.
Rev. 0.20
2011-10-04
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