NEC Network Controller uPD98502 - Manual (Page 314)

CHAPTER 6 USB CONTROLLER
314 Preliminary User’s Manual S15543EJ1V0UM
6.2.4 U_GSR1 (USB General Status Register 1)
This register indicates the current status of USB Controller.
Bits Field R/W Default Description
31 GSR2 RC 0 If some bits of General Status Register 2 are set to ‘1’s and the
corresponding bits in Interrupt Mask Register 2 are set to ‘1’s, this GSR2 bit
will be set to a ‘1’.
30:24 Reserved R 0 Reserved for future use
23 TMF RC 0 Tx MailBox Full:
Bit that indicates transmit MailBox area is full. This bit is set to a ‘1’ when the
USB Tx MailBox Read Address and the USB Tx MailBox Write Address get
equal. This bit is reset to a ‘0’ when the V
R
4120A reads this register.
22 RMF RC 0 Rx MailBox Full:
Bit that indicates receive MailBox area is full. This bit is set to a ‘1’ when the
USB Rx MailBox Read Address and the USB Rx MailBox Write Address get
equal. This bit is reset to a ‘0’ when the V
R
4120A reads this register.
21 RPE2 RC 0 Rx Pool2 Empty:
Bit that indicates receive Pool2 is empty.
This bit is reset to a ‘0’ when the V
R
4120A reads this register.
20 RPE1 RC 0 Rx Pool1 Empty:
Bit that indicates receive Pool1 is empty.
This bit is reset to a ‘0’ when the V R 4120A reads this register.
19 RPE0 RC 0 Rx Pool0 Empty:
Bit that indicates receive Pool0 is empty.
This bit is reset to a ‘0’ when the V R 4120A reads this register.
18 RPA2 RC 0 Rx Pool2 Alert:
This bit is set to a ‘1’ when the number of Buffer Directories remaining in
receive Pool2 gets equal to 4 times of the AL field value in the Rx Pool2
Information Register.
This bit is reset to a ‘0’ when the V R 4120A reads this register.
17 RPA1 RC 0 Rx Pool1 Alert:
This bit is set to a ‘1’ when the number of Buffer Directories remaining in
receive Pool1 gets equal to 4 times of the AL field value in the Rx Pool1
Information Register.
This bit is reset to a ‘0’ when the V
R
4120A reads this register.
16 RPA0 RC 0 Rx Pool0 Alert:
This bit is set to a ‘1’ when the number of Buffer Directories remaining in
receive Pool0 gets equal to 4 times of the AL field value in the Rx Pool0
Information Register.
This bit is reset to a ‘0’ when the V
R
4120A reads this register.
15:11 Reserved R 0 Reserved for future use
10 DER RC 0 DMA Error:
Bit that indicates that an error occurred during DMA transfer. This bit is set to
a ‘1’ if an error occurs on the Internal BUS during DMA transfer.
This bit is reset to a ‘0’ when the V R 4120A reads this register.
9 EP2FO RC 0 EP2 FIFO Error:
Bit that indicates that an overrun has occurred for the FIFO of EndPoint2
(Isochronous OUT). When the FIFO becomes full while EndPoint2 is
performing a transaction, USB Controller can no longer receive data and all
data subsequent is discarded. Should this occur, this bit is set to a ‘1’.
This bit is reset to a ‘0’ when the V
R
4120A reads this register.