Interface And Signals; Qspi Block Diagram - Motorola ColdFire MCF5281 User Manual

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.
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.
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.
Queue Control
Block
Queue
Pointer
Comparator
End Queue
Pointer
Control Logic
Status
Regs
Control
Regs
Delay
Counter
Internal Bus
System Clock
22-2
4
Done
QSPI
Address
Register
4
4
Chip
Select
Logic
4
Array
Command
Divide by 2
Figure 22-1. QSPI Block Diagram
MCF5282 User's Manual
80-Byte
QSPI
RAM
msb
8/16 Bit Shift Reg.
Rx/Tx Data Reg.
Baud Rate
Generator
QSPI
Data
Register
lsb
QSPI_Din
QSPI_Dout
4
QSPI_CS[3:0]
QSPI_CLK
MOTOROLA