NEC switch User Manual
Page 115
CHAPTER 8 USB FUNCTION
User’s Manual U12978EJ3V0UD
115
(6) Data packet transmit reservation register (DTXRSV)
This register sets the bank where the data packet to be transmitted is stored. By setting each flag of this
register, the stored data is transmitted following normal reception of the IN token packet.
DTXRSV is set with a 1-bit or 8-bit memory manipulation instruction. When DTXRSV is used in combination
with the handshake packet transmit reservation register (HTXRSV) as the 16-bit register USBCON, DTXRSV is
set with a 16-bit memory manipulation instruction.
RESET input sets DTXRSV to 00H.
SETUP reception
Note
also sets DTXRSV to 00H.
Note SETUP reception implies the satisfaction of all the following three conditions.
• Matching of address
• Endpoint 0 received
• No error in reception
Figure 8-15. Format of Data Packet Transmit Reservation Register
Symbol
6
7
5
4
3
2
1
0
0
0
0
0
DT11EN DT10EN DT01EN DT00EN
DT11EN
Transmit reservation flag for transmit bank 1 (Endpoint 1)
0
1
FF15H
Address
DTXRSV
After reset
00H
R/W
R/W
No data is transmitted.
Stored data is transmitted when all the following conditions are satisfied in EOP during IN packet reception.
Setting is disabled during control read transmission.
INRX (Internal signal) = 1, ADRRST = 1, END1RX = 1, TBYER = 0, TBITER = 0, CRC5ER = 0
DT10EN
Transmit reservation flag for transmit bank 1 (Endpoint 0)
0
1
No data is transmitted.
Stored data is transmitted when all the following conditions are satisfied in EOP during IN packet reception.
INRX (internal signal) = 1, TIDRST = 1, ADRRST = 1, END0RX = 1, TBYER = 0, TBITER = 0, CRC5ER = 0
DT00EN
Transmit reservation flag for transmit buffer 0 (Endpoint 0)
0
1
No data is transmitted.
Stored data is transmitted when all the following conditions are satisfied in EOP during IN packet reception.
INRX (internal signal) = 1, TIDRST = 1, ADRRST = 1, END0RX = 1, TBYER = 0, TBITER = 0, CRC5ER = 0
DT01EN
Transmit reservation flag for transmit buffer 0 (Endpoint 1)
0
1
No data is transmitted.
Stored data is transmitted when all the following conditions are satisfied in EOP during IN packet reception.
Setting is disabled during control read transmission.
INRX (internal signal) = 1, ADRRST = 1, END1RX = 1, TBYER = 0, TBITER = 0, CRC5ER = 0
Caution Setting bits 1 and 3 (DT01EN, DT11EN) is prohibited during control transfer.