4 data receive mode – NEC Network Controller uPD98502 User Manual
Page 348
CHAPTER 6 USB CONTROLLER
348
Preliminary User’s Manual S15543EJ1V0UM
(a) If any unused Buffer Directories remain in the pool (when the RNOD field in the Pool Information Register is
set to grater than 0), USB Controller adds the number in the NOD field of the command to the RNOD field
of the Pool Information Register.
(b) When the pool is empty (when the RNOD field in the Pool Information Register is 0), USB Controller loads
the value set in the NOD field of the command into the RNOD field of the Pool Information Register.
Furthermore, it loads the value written in the USB Command Extension Register into the Pool Address
Register.
6.6.4 Data receive mode
USB Controller has different receive processing every EndPoint and receive mode.
The receive mode is determined by RM field (Bits 20:19) in USB EP2 Control Register (Address 1000_1028H) and
USB EP4 Control Register (Address 1000_1030H). There are four kinds of receive processing.
(1)
EndPoint0, EndPoint6
(2)
EndPoint2, EndPoint4 Normal Mode
(3)
EndPoint2, EndPoint4 Assemble Mode
(4)
EndPoint2, EndPoint4 Separate Mode
Each processing is explained below.