Motorola MCF5281 사용자 설명서
22-2
MCF5282 User’s Manual
MOTOROLA
Module Description
22.3.1 Interface and Signals
The module provides access to as many as 15 devices with a total of seven signals:
QSPI_Dout, QSPI_Din, QSPI_CLK, QSPI_CS0, QSPI_CS1, QSPI_CS2, and QSPI_CS3.
QSPI_Dout, QSPI_Din, QSPI_CLK, QSPI_CS0, QSPI_CS1, QSPI_CS2, and QSPI_CS3.
Peripheral chip-select signals, QSPI_CS[3:0], are used to select an external device as the
source or destination for serial data transfer. Signals are asserted at a logic level
corresponding to the value of the QSPI_CS[3:0] bits in the command RAM whenever a
command in the queue is executed. More than one chip-select signal can be asserted
simultaneously.
source or destination for serial data transfer. Signals are asserted at a logic level
corresponding to the value of the QSPI_CS[3:0] bits in the command RAM whenever a
command in the queue is executed. More than one chip-select signal can be asserted
simultaneously.
Although QSPI_CS[3:0] will function as simple chip selects in most applications, up to 15
devices can be selected by decoding them with an external 4-to-16 decoder.
devices can be selected by decoding them with an external 4-to-16 decoder.
Figure 22-1. QSPI Block Diagram
Queue Control
Block
Queue
Pointer
System Clock
4
Done
Comparator
End Queue
Pointer
Status
Regs
Delay
Counter
Control Logic
Control
Regs
80-Byte
QSPI
RAM
Chip
Select
Command
Divide by 2
Baud Rate
Generator
msb
lsb
Logic
Array
Array
QSPI_CLK
QSPI_CS[3:0]
QSPI_Din
8/16 Bit Shift Reg.
Rx/Tx Data Reg.
QSPI_Dout
4
4
4
Internal Bus
4
QSPI
Address
Register
QSPI
Data
Register