NXP Semiconductors K22F series, Reference Manual, Page: 683 / 1407

• Enabled — When enabled, the EzPort steals access to the flash memory, preventing
access from other cores or peripherals. The rest of the microcontroller is disabled to
avoid conflicts. The flash is configured for NVM Special mode.
• Disabled — When the EzPort is disabled, the rest of the microcontroller can access
flash memory as normal.
The EzPort provides a simple interface to connect an external device to the flash memory
on board a 32 bit microcontroller. The interface itself is compatible with the SPI
interface, with the EzPort operating as a slave, running in either of the two following
modes. The data is transmitted with the most significant bit first.
• CPOL = 0, CPHA = 0
• CPOL = 1, CPHA = 1
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.
This allows the signal to be shared among several different EzPort (or compatible)
devices in parallel, as long as they have different chip-selects.
30.2 External signal descriptions
After the table of EzPort external signals, subsequent sections explain the signals in more
detail.
Table 30-1. EzPort external signals
JTAG (cJTAG)
Signal
External Signal Name I/O
TCK (TCKC) EZP_CK EzPort Clock Input
TMS (TMSC) EZP_CS EzPort Chip Select Input
TDI (TDIC) EZP_D EzPort Serial Data In Input
TDO (TDOC) EZP_Q EzPort Serial Data Out Output
30.2.1 EzPort Clock (EZP_CK)
EZP_CK is the 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.
Chapter 30 EzPort
K22F Sub-Family Reference Manual, Rev. 4, 08/2016
NXP Semiconductors 683