Description
Interrupt Source
This condition occurs only in legacy SPI mode. When
0, the RX FIFO buffer is empty. When 1, the RX FIFO
buffer is not empty.
RX FIFO not empty
This condition occurs only in legacy SPI mode. When
0, the RX FIFO buffer is not full. When 1, the RX FIFO
buffer is full.
RX FIFO full
Indirect Read Partition of SRAM is full and unable to
immediately complete indirect operation
Indirect read partition overflow
Interface Signals
The quad SPI controller provides four chip select outputs to allow control of up to four external quad SPI
flash devices. The outputs serve different purposes depending on whether the device is used in single, dual,
or quad operation mode. Table 12–3 lists the I/O pin use of the quad SPI controller interface signals for each
operation mode.
Table 12-4: Interface Signals
Function
Direction
Mode
Signal
Data output 0
Output
Single
data[0]
Data I/O 0
Bidirectional
Dual or quad
Data input 0
Input
Single
data[1]
Data I/O 1
Bidirectional
Dual or quad
Active low write protect
Output
Single or dual
data[2]
Data I/O 2
Bidirectional
Quad
Data I/O 3
Bidirectional
Single, dual, or quad
data[3]
Active low slave select 0
Output
Single, dual, or quad
ss_n[0]
Active low slave select 1
ss_n[1]
Active low slave select 2
ss_n[2]
Active low slave select 3
ss_n[3]
Serial clock
sclk
Altera Corporation
Quad SPI Flash Controller
12-13
Interface Signals
cv_54012
2013.12.30