NEC switch - Manual (Page 108)

CHAPTER 8 USB FUNCTION
User’s Manual U12978EJ3V0UD
108
(10) Data/handshake PID compare register (DIDCMP)
This register sets the data/handshake packet ID to be received. If this register value and the value of the
receive data PID (USBRD) match during data/handshake packet reception coincide, the DIDRST (bit 1 of the
data/handshake packet receive result store register (DRXRSL)) is set.
DIDCMP is set with an 8-bit memory manipulation instruction.
RESET input sets DIDCMP to C3H.
SETUP reception Note also sets DIDCMP to C3H.
Note SETUP reception implies the satisfaction of all the following three conditions.
• Matching of address
• Endpoint 0 received
• No error in reception
Figure 8-9. Configuration of DIDCMP
00H
07H 06H 05H 04H 03H 02H 01H 00H
11H
18H
USBPOW address
USBPOB address
USBRD
Data area (8 bytes)
DIDCMP
Match signal (DIDRST)
Receive data bank