How-To Guide

Table Of Contents
R01UH0823EJ0110 Rev.1.10 Page 913 of 1852
Nov 30, 2020
RX23W Group 32. USB 2.0 Host/Function Module (USBc)
ACLRM Bit (Auto Buffer Clear Mode)
Enables or disables auto buffer clear mode for the relevant pipe.
To delete the information in the FIFO buffer assigned to the relevant pipe completely, write 1 and then 0 to the ACLRM
bit continuously.
Table 32.10 shows the information cleared by writing 1 and 0 to the ACLRM bit continuously and the cases in which
clearing the information is necessary.
BSTS Flag (Buffer Status Flag)
Indicates the FIFO buffer status for the relevant pipe.
The meaning of the BSTS flag depends on the settings of the PIPECFG.DIR bit, PIPECFG.BFRE bit, and
DnFIFOSEL.DCLRM bits as shown in
Table 32.9.
Table 32.10 Information Cleared by USB by Setting the ACLRM Bit = 1
No. Information Cleared by ACLRM Bit Manipulation Cases in which Clearing Information is Necessary
1 All the information in the FIFO buffer assigned to the selected
pipe
When the pipe is to be initialized
2 The interval count value when the selected pipe is for
interrupt transfer and the host controller is selected
When the interval count value is to be reset
3 Internal flags concerning the PIPECFG.BFRE bit When the PIPECFG.BFRE setting is modified
4 Internal flags concerning the transaction count When the transaction count function is forcibly terminated