R01UH0823EJ0100 Rev.1.00
Page 905 of 1823
Jul 31, 2019
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.
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 32.10
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