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CHAPTER 6 USB CONTROLLER
430
Preliminary User’s Manual S14767EJ1V0UM00
6.6.5 V
R
4120A RISC processor receive processing
This section explains the processing that the V
R
4120A RISC Processor must perform when data is being sent.
Figure 6-20. V
R
4120A RISC Processor Receive Processing
Sets Pool initialization
Reads USB General Status
Register 1
(If necessary)
Adds Buffer Directory to Pool
Receive is End
Yes
No
Receives the data
from USB.
Reads U_RMRA register
Reads Rx indication
Updates read pointer in mailbox
Read processing of
Rx indication
(1)
(2)
(4)
(5)
(6)
(7)
(3)
Sets Rx Pool
Numbers (1) to (7) do not indicate the order in which the V
R
4120A RISC Processor must perform processing.
Instead, these numbers correspond to those in the following explanation.
(1)
(2)
(3)
(4)
(5)
First, as part of initialization, the V
R
4120A RISC Processor must make the necessary Pool settings.
For receiving, the V
R
4120A RISC Processor must add Buffer Directories to the Pool, if necessary.
The V
R
4120A RISC Processor reads the USB General Status Register 1.
The V
R
4120A RISC Processor checks whether receiving has ended.
If receiving has ended, the V
R
4120A RISC Processor reads the receive mailbox setting register (USB Rx
MailBox Read Address Register Address: 88H) to determine the address of Mailbox V
R
4120A RISC
Processor must read in the next time.
Then, the V
R
4120A RISC Processor reads the Rx indication from the indicated mailbox.
The V
R
4120A RISC Processor updates the receive mailbox read address (USB Rx MailBox Read Address
Register).
(6)
(7)