UM10562 Datasheet, PDF (340/942 Pages) NXP Semiconductors – LPC408x/407x User manual

NXP Semiconductors
UM10562
Chapter 12: LPC408x/407x USB device controller
12.10.4.3 USB Endpoint Index register
Each endpoint has a register carrying the MaxPacketSize value for that endpoint. This is
in fact a register array. Hence before writing, this register is addressed through the
USBEpIn register.
The USBEpIn register will hold the physical endpoint number. Writing to USBMaxPSize
will set the array element pointed to by USBEpIn. USBEpIn is a write-only register.
Table 268. USB Endpoint Index register (EPIN - address 0x2008 C248) bit description
Bit Symbol
Description
4:0 PHY_EP
Physical endpoint number (0-31)
31:5 -
Reserved. Read value is undefined, only zero should be written.
Reset value
0
NA
12.10.4.4 USB MaxPacketSize register
On reset, the control endpoint is assigned the maximum packet size of 8 bytes. Other
endpoints are assigned 0. Modifying USBMaxPSize will cause the endpoint buffer
addresses within the EP_RAM to be recalculated. This is a multi-cycle process. At the
end, the EP_RLZED bit will be set in USBDevIntSt (Table 256). USBMaxPSize array
indexing is shown in Figure 42. USBMaxPSize is a read/write register.
Table 269. USB MaxPacketSize register (MAXPSIZE - address 0x2008 C24C) bit description
Bit Symbol
Description
9:0 MPS
The maximum packet size value.
31:10 -
Reserved. Read value is undefined, only zero should be written.
Reset value
0x008^[1]
NA
[1] Reset value for EP0 and EP1. All other endpoints have a reset value of 0x0.
ENDPOINT INDEX
MPS_EP0
MPS_EP31
The Endpoint Index is set via the USBEpIn register. MPS_EP0 to MPS_EP31 are accessed via the
USBMaxPSize register.
Fig 42. USB MaxPacketSize register array indexing
UM10562
User manual
All information provided in this document is subject to legal disclaimers.
Rev. 1 — 13 September 2012
© NXP B.V. 2012. All rights reserved.
340 of 942