mcf51jf128 Freescale Semiconductor, Inc, mcf51jf128 Datasheet - Page 579

• Manufacturer Part Number: mcf51jf128
• Description: Mcf51jf128 Reference Manual
• Manufacturer: Freescale Semiconductor, Inc

The EzPort provides a simple interface to connect an external device to the flash memory
on board a 32 bit micro-controller. The interface itself is compatible with the SPI
interface (with the EzPort operating as a slave) running in either of the two following
modes with data transmitted most significant bit first:
Commands are issued by the external device to erase, program or read the contents of the
flash memory. The serial data out from the EzPort is tri-stated unless data is being driven,
allowing the signal to be shared among several different EzPort (or compatible) devices
in parallel, provided they have different chip selects.
25.2 External Signal Description
The following table contains a list of EzPort external signals, and the following sections
explain them in detail.
25.2.1 EzPort Clock (EZP_CK)
Serial clock for data transfers. The serial data in (EZP_D) and chip select (EZP_CS) are
registered on the rising edge of EZP_CK while serial data out (EZP_Q) is driven on the
falling edge of EZP_CK.
The maximum frequency of the EzPort clock is half the system clock frequency for all
commands except when executing the Read Data or Read FlexRAM commands. When
executing these commands, the EzPort clock has a maximum frequency of one-eighth the
system clock frequency.
Freescale Semiconductor, Inc.
• CPOL = 0, CPHA = 0
• CPOL = 1, CPHA = 1
EZP_CK
EZP_CS
EZP_Q
EZP_D
Name
Table 25-1. EzPort External Signal Descriptions
MCF51JF128 Reference Manual, Rev. 2, 03/2011
EzPort Serial Data Out
EzPort Serial Data In
EzPort Chip Select
Preliminary
EzPort Clock
Description
Chapter 25 EzPort
Output
Input
Input
Input
I/O
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