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CHAPTER 8 USB FUNCTION
104
8.2 USB Function Features
The features of the on-chip USB function provided for the
μ
PD789800 subseries are described below.
(1)
Video display devices and human interface devices are assumed to be the target applications. For this
reason, only Endpoint0 for control transfer and Endpoint1 for interrupt transfer are supported.
1.5-Mbps (low speed) data transfer using a 6.0-MHz main system clock is supported.
The following buffers are provided on-chip:
Receive data PID
: 1 bank (3 bytes)
Receive data address
: 1 bank (9 bytes)
Send data bank address: 2 banks (9 bytes x 2)
NRZI (Non Return Zero Invert) decode/encode function specified by the USB communication protocol, bit
stuffing function, and on-chip CRC (Cyclic Redundancy Check) function are also provided and
automatically executed.
(2)
(3)
(4)
8.3 USB Function Configuration
The USB function consists of the following hardware.
Table 8-1. Configuration of USB Function
Item
Configuration
Buffer
Receive bank switching ID detection buffer (internal buffer)
Register
Send/receive pointer (USBPOW)
Receive token PID (USBRTP)
Receive token packet address L, H (USBRAL, USBRAH)
Receive data PID (USBRD)
Receive data address (USBR0-USBR7)
Send data PID bank 0 (USBTD0)
Send data bank 0 address (USBT00-USBT07)
Send data PID bank 1 (USBTD1)
Send data bank 1 address (USBT10-USBT17)
Data/handshake packet receive byte number counter (DRXCON)
Data packet send byte number counter 0, 1 (DTXCO0, DTXCO1)
Token PID compare register (TIDCMP)
Token address compare register (ADRCMP)
Data/handshake PID compare register (DIDCMP)
Control register
USB receiver enable register (USBMOD)
Data/handshake packet receive mode register (URXMOD)
Packet receive status register (RXSTAT)
Data/handshake packet receive result store register (DRXRSL)
Token packet receive result store register (TRXRSL)
Data packet send reservation register (DTXRSV)
Handshake packet send reservation register (HTXRSV)
USB timer start reservation control register (USBTCL)
Remote wake-up control register (REMWUP)