GD32W51x User Manual
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which is judge as an unaccessable transfer(such as a secure transfer trys to access a
nonsecure area), and generate a hard-fault.
If any of above condition happens, AHB will generate an error .The effect of the error depends
on the AHB master.
In this mode, byte, half-word, and word single or burst access are supported.
CPU: a hard fault is generated
DMA: transfer error is generated, and the corresponding DMA channel is disabled.
Execute in place (XIP) is also supported, where the QSPI anticipates the next MCU access
and load in advance the byte at the following address, if the subsequent access is indeed
made at a continuous address, the access with be completed faster since the value is already
prefetched. Otherwise, the read sequence is restarted, polling CSN low before the read
sequence starts.
After the FIFO is full, the QSPI enters hold state, in which no SCK is sent, CSN is maintained
low during this period. If timeout counter is enabled, CSN will be pulled high when hold state
contains number of SCK clock cycles equals to TMOUT control field.
At the beginning of a transfer, BUSY goes high before CSN falls, and is cleared when a
timeout occurred or abort/disable is issued.
22.4.4.
FMC mode
This mode is supported based on memory map mode with a highest priority, QSPI read
address is word align. FMC mode will abort any transfer except status polling mode. But when
an indirect write mode is aborted, QSPI will not access FMC mode immediately because of
the time requirement of external flash. As for staus polling mode, in order not to block the
FMC mode, add timeout of staus polling.
NOTE: this mode will abort the normal transfer, and user should check the QSPI_BYTE_CNT
register to know how many bytes are aborted. In this mode, ABORT bit in QSPI_CTL bit
should be set to 1 to make sure that the data in FIFO will be stored until they are pushed or
popped by software.
This mode will abort indirect mode and status mode. But when last mode is indirect write
mode, FMC
mode won’t start right after indirect write mode is aborted or indirect write mode
is finished, FMC mode will start after WTCNT which is specified by register QSPI_WTCNT.
When FMC mode is set to abort a staus-polling transfer, status-polling will still to work to
match status until the time out flag for staus-polling mode which is specified by register
QSPI_
SPTMOUT, a hard fault is generated.