Renesas R5S72621 User Manual

 

Section 26   USB 2.0 Host/Function Module 

R01UH0134EJ0400  Rev. 4.00  

 

Page 1379 of 2108 

Sep 24, 2014 

 

 

 
SH7262 Group, SH7264 Group 

12 

 0 

R 

Reserved 

This bit is always read as 0. The write value should 
always be 0. 

11 to 0 

DTLN[11:0] 

H'000 

R 

Receive Data Length 

Indicates the length of the receive data. 

While the FIFO buffer is being read, these bits 
indicate the different values depending on the RCNT 
bit value as described below.  

  RCNT = 0: 

This module sets these bits to indicate the length 
of the receive data until all the received data has 
been read from a single FIFO buffer plane. 

While BFRE is 1, these bits retain the length of 
the receive data until BCLR is set to 1 even after 
all the data has been read.  

  RCNT = 1: 

This module decrements the value indicated by 
these bits each time data is read from the FIFO 
buffer. (The value is decremented by one when 
MBW is 00, by two when MBW is 01, and by four 
when MBW is 10.) 

This module sets these bits to 0 when all the data 
has been read from one FIFO buffer plane. However, 
in double buffer mode, if data has been received in 
one FIFO buffer plane before all the data has been 
read from the other plane, this module sets these bits 
to indicate the length of the receive data in the 
former plane when all the data has been read from 
the latter plane. 

Note: When RCNT is 1, it takes 10 bus cycles for 
these bits to be updated after the FIFO port has been 
read. 

Notes:  1.  Only 0 can be read and 1 can be written.  

 

2.  Only 1 can be written.