Component - EMIF V1.20

PSoC® Creator™ Component Datasheet
External Memory Interface (EMIF)
1.20
Features
 8-, 16-, 24-bit address bus
width






8-, 16-bit data bus width
Supports external synchronous
memory
Supports external
asynchronous memory
Supports custom interface for memory
Supports a range of speeds of external memories
(from 5 to 200 ns)
Supports external memory power-down, sleep, and
wakeup modes
General Description
The EMIF component enables access by the CPU or DMA to memory ICs external to the
PSoC 3/5LP. It facilitates setup of the EMIF hardware, as well as UDBs and GPIOs as required.
The EMIF can control synchronous and asynchronous memories without the need to configure
any UDBs in synchronous and asynchronous modes. In UDB mode, UDBs must be configured to
generate external memory control signals.
When to Use an EMIF
The EMIF is used to expand available memory space. This allows for expanded data storage in
off-chip memory devices. External memory ICs connected to a PSoC are typically intended to
hold large arrays of data, such as text, audio, or video content. Other expected applications
include data logging and use as a buffer for external LCD pixel data.
Cypress Semiconductor Corporation • 198 Champion Court • San Jose, CA 95134-1709 • 408-943-2600
Document Number: 001-83032 Rev. *A
Revised November 9, 2015
External Memory Interface (EMIF)
PSoC® Creator™ Component Datasheet
Input/Output Connections
This section describes the various input and output connections for the EMIF. An asterisk (*) in
the list of I/Os states that the I/O may be hidden on the symbol under the conditions listed in the
description of that I/O.
udb_ready – Input*
Signal from external logic, indicating to PHUB that the AHB bus transaction is complete (active
high). This input is visible when the External Memory Type parameter is set to Custom.
xmem_wr – Output*
Generic write signal to custom interface (active high). Signal from external logic, indicating to
PHUB that the AHB bus transaction is complete (active high). This output is visible when the
External Memory Type parameter is set to Custom.
xmem_rd – Output*
Generic read signal to custom interface (active high). This output is visible when the External
Memory Type parameter is set to Custom.
cen – Output*
Chip enable to external memory (active low). This output is visible when the External Memory
Type parameter is set to Synchronous or Asynchronous.
wen – Output*
Write enable to external memory (active low). This output is visible when the External Memory
Type parameter is set to Synchronous or Asynchronous.
oen – Output*
Output enable to external memory (active low). This output is visible when the External Memory
Type parameter is set to Synchronous or Asynchronous.
mem_clk – Output*
Clock to external synchronous memory. This output is visible when the External Memory Type
parameter is set to Synchronous.
adscn – Output*
Address strobe to external synchronous memory (active low). This output is visible when the
External Memory Type parameter is set to Synchronous.
Page 2 of 16
Document Number: 001-83032 Rev. *A
PSoC® Creator™ Component Datasheet
External Memory Interface (EMIF)
mem_sleep – Output*
Sleep signal to external synchronous memory sleep pin (active high). This output is visible when
the External Memory Type parameter is set to Synchronous.
Schematic Macro Information
By default, the PSoC Creator Component Catalog contains schematic macro implementations
for the EMIF component. These macros contain already connected output pins. Schematic
macros are available both for asynchronous External Memory Interface and synchronous
External Memory Interface.
Figure 1. Asynchronous External Memory Interface Schematic Macro
Figure 2. Synchronous External Memory Interface Schematic Macro
Document Number: 001-83032 Rev. *A
Page 3 of 16
External Memory Interface (EMIF)
PSoC® Creator™ Component Datasheet
Component Parameters
Drag an EMIF onto your design and double click it to open the Configure dialog.
Figure 3. Configure EMIF Dialog
The EMIF provides the following parameters:
External Memory Type
Determines external memory type. Default external memory type is Asynchronous.
Address Width (bits)
Determines the number of bits in the address bus for external memory. The default address bus
width is 24 bits.
Data Width (bits)
Determines the number of bits in the data bus for external memory. The default data bus width is
16 bits.
External Memory Speed (ns)
Determines external memory speed in ns. The default external memory speed is 30 ns.
Page 4 of 16
Document Number: 001-83032 Rev. *A
PSoC® Creator™ Component Datasheet
External Memory Interface (EMIF)
Bus Clock Frequency
Shows the selected Bus Clock frequency in megahertz.
Memory Transactions

Write Cycle Length – Shows the write cycle length in nanoseconds. The Bus Clock
frequency cycles are shown in parentheses.

Read Cycle Length – Shows the read cycle length in the nanoseconds. The Bus Clock
frequency cycles are shown in parentheses.

Signal wen Pulse Width (Twel) – Shows the Twel parameter (write enable signal pulse
width) in nanoseconds. See the DC and AC Electrical Characteristics section for details.

Signal oen Pulse Width (Toel) – Shows the Toel parameter (write enable signal pulse
width) in nanoseconds. See the DC and AC Electrical Characteristics section for details.
Application Programming Interface
Application Programming Interface (API) routines allow you to configure the component using
software. The following table lists and describes the interface to each function. The subsequent
sections cover each function in more detail.
By default, PSoC Creator assigns the instance name “EMIF_1” to the first instance of a
component in a given design. You can rename it to any unique value that follows the syntactic
rules for identifiers. The instance name becomes the prefix of every global function name,
variable, and constant symbol. For readability, the instance name used in the following table is
“EMIF.”
Function
Description
EMIF_Start()
Calls EMIF_Init() and EMIF_Enable().
EMIF_Stop()
Disables the EMIF block. Returns all associated I/O ports and pins to HI-Z mode
EMIF_Init()
Initializes or restores the EMIF configuration to the current customizer state
EMIF_Enable()
Enables the EMIF hardware block, associated I/O ports and pins
EMIF_ExtMemSleep()
Sets the external memory sleep signal high; note that depending on the type of
external memory IC used, the signal may need to be inverted
EMIF_ExtMemWakeup()
Sets the external memory sleep signal low; note that depending on the type of
external memory IC used, the signal may need to be inverted
EMIF_SaveConfig()
Saves the user configuration of the EMIF nonretention registers. This routine is called
by EMIF_Sleep() to save the component configuration before entering sleep
EMIF_Sleep()
Stops the EMIF operation and saves the user configuration along with the enable
state of the EMIF
Document Number: 001-83032 Rev. *A
Page 5 of 16
External Memory Interface (EMIF)
Function
PSoC® Creator™ Component Datasheet
Description
EMIF_RestoreConfig()
Restores the user configuration of the EMIF nonretention registers. This routine is
called by EMIF_Wakeup() to restore the component configuration when exiting sleep
EMIF_Wakeup()
Restores the user configuration and restores the enable state
void EMIF_Start(void)
Description:
This is the preferred method to begin component operation. EMIF_Start() calls the
EMIF_Init() function, and then calls the EMIF_Enable() function.
Parameters:
None
Return Value: None
Side Effects:
None
void EMIF_Stop(void)
Description:
Disables the EMIF block. Returns all associated I/O ports and pins to HI-Z mode
Parameters:
None
Return Value: None
Side Effects:
None
void EMIF_Init(void)
Description:
Initializes or restores the component according to the customizer Configure dialog settings. It
is not necessary to call EMIF_Init() because the EMIF_Start() routine calls this function and
is the preferred method to begin component operation.
Parameters:
None
Return Value: None
Side Effects:
None
void EMIF_Enable(void)
Description:
Activates the hardware and begins component operation. It is not necessary to call
EMIF_Enable() because the EMIF_Start() routine calls this function, which is the preferred
method to begin component operation.
Parameters:
None
Return Value: None
Side Effects:
Page 6 of 16
None
Document Number: 001-83032 Rev. *A
PSoC® Creator™ Component Datasheet
External Memory Interface (EMIF)
void EMIF_ExtMemSleep(void)
Description:
Sets the ‘mem_pd’ bit in the EMIF_PWR_DWN register. This sets the external memory sleep
signal high. Depending on the type of external memory IC used, the signal may need to be
inverted.
Parameters:
None
Return Value: None
Side Effects:
None
void EMIF_ExtMemWakeup(void)
Description:
Resets the ‘mem_pd’ bit in the EMIF_PWR_DWN register. This sets the external memory
sleep signal low. Depending on the type of external memory IC used, the signal may need to
be inverted
Parameters:
None
Return Value: None
Side Effects:
None
void EMIF_SaveConfig(void)
Description:
This function saves the component configuration. This will save nonretention registers. This
function will also save the current component parameter values, as defined in the Configure
dialog or as modified by appropriate APIs. This function is called by the EMIF_Sleep()
function.
Parameters:
None
Return Value: None
Side Effects:
None
Document Number: 001-83032 Rev. *A
Page 7 of 16
External Memory Interface (EMIF)
PSoC® Creator™ Component Datasheet
void EMIF_Sleep(void)
Description:
This is the preferred routine to prepare the component for sleep. The EMIF_Sleep() routine
saves the current component state. Then it calls the EMIF_Stop() function and calls
EMIF_SaveConfig() to save the hardware configuration.
Call the EMIF_Sleep() function before calling the CyPmSleep() or the CyPmHibernate()
function. Refer to the PSoC Creator System Reference Guide for more information about
power management functions.
Parameters:
None
Return Value: None
Side Effects:
None
void EMIF_RestoreConfig(void)
Description:
This function restores the component configuration. This will restore nonretention registers.
This function will also restore the component parameter values to what they were prior to
calling the EMIF_Sleep() function.
Parameters:
None
Return Value: None
Side Effects:
Calling this function without first calling the EMIF_Sleep() or EMIF_SaveConfig() function
may produce unexpected behavior.
void EMIF_Wakeup(void)
Description:
This is the preferred routine to restore the component to the state when EMIF_Sleep() was
called. The EMIF_Wakeup() function calls the EMIF_RestoreConfig() function to restore the
configuration. If the component was enabled before the EMIF_Sleep() function was called,
the EMIF_Wakeup() function will also re-enable the component.
Parameters:
None
Return Value: None
Side Effects:
Calling the EMIF_Wakeup() function without first calling the EMIF_Sleep() or
EMIF_SaveConfig() function may produce unexpected behavior.
Defines
CYDEV_EXTMEM_BASE – Convenience macro for locating parameters in external memory.
The address space for the EMIF is outside of the lower 64K address space. In order to access
the EMIF you need to use the extended range macros CY_GET_XTND_REG8() and
CY_SET_XTND_REG8(). Refer to the System Reference Guide for more details on these
macros.
Page 8 of 16
Document Number: 001-83032 Rev. *A
PSoC® Creator™ Component Datasheet
External Memory Interface (EMIF)
External Memory Interface
16 Bit Memories:
DMA Transfers: For DMA transfers to/from 16 bit external memory, the BURSTCNT (Burst
Count) channel configurations of odd values are not supported. This is because 8 bit transfers
are not supported on 16 bit interface.
CPU Transfers: Since PSoC 3 is 8-bit processor, we cannot access 16 bit memory from CPU.
PSoC 5LP CPU is 32-bit processor. It can access 16 bit memories. The constraint here is, it
should not initiate 8 bit transfers to 16 bit memories.
8 Bit Memories:
DMA Transfers: For DMA transfers to/from 8 bit external memory, irrespective of XFRCNT
(Transfer Count), the BURSTCNT (Burst Count) should always be 1.
CPU Transfers: Since PSoC 3 is 8 bit processor, there are no constraints here.
PSoC 5LP should only initiate 8 bit requests for 8 bit memories.
External memory interface Address Map
PSoC 3 External memory interface XDATA Data Address Map
Address Range:
0x800000 – 0xFFFFFF
PSoC 5LP External memory interface Memory Address Map
Address Range:
0x60000000 – 0x61FFFFFF
Sample Firmware Source Code
PSoC Creator provides numerous example projects that include schematics and example code
in the Find Example Project dialog. For component-specific examples, open the dialog from the
Component Catalog or an instance of the component in a schematic. For general examples,
open the dialog from the Start Page or File menu. As needed, use the Filter Options in the
dialog to narrow the list of projects available to select.
Refer to the “Find Example Project” topic in the PSoC Creator Help for more information.
Document Number: 001-83032 Rev. *A
Page 9 of 16
External Memory Interface (EMIF)
PSoC® Creator™ Component Datasheet
Functional Description
This component, and PSoC Creator in general, does not provide any direct support for locating
code, variables, structures, or arrays in external memory. However, there is nothing in either this
component or in PSoC Creator that prevents an advanced user from creating or modifying
source code, a linker script, or any other source file, for that purpose.
Initialized variables should not be placed in external memory. Do not locate code, variables,
structures, and arrays autogenerated by PSoC Creator in external memory.
The PSoC EMIF hardware and associated GPIO ports support up to a 24-bit address bus, and
an 8-bit or 16-bit data bus.
External memories require up to six GPIO ports to connect address, data, and control lines: one
to three ports for address, one to two for data, and one for control. For address and data, the
entire port must be selected. Unused pins in the control port are still available as GPIOs.
When an EMIF component is placed onto the project schematic, it is important that I/O port
designations be set for address and data. Designation of address and data ports is not done on
the symbol or schematic; instead, it is done in the Pins tab of the Design-Wide Resources
window. Control signals are shown on the component symbol as terminals; the terminals should
be routed to Pin components in the usual manner.
There are three EMIF types – asynchronous, synchronous, or (rarely used) custom. The type
selected determines the size of the symbol, the number of terminals in the symbol, and some of
the text in the symbol. The custom version of the component is the only one with an input
terminal, udb_ready. It is expected that the xmem_wr and xmem_rd signals will be tied to UDBbased logic which will both generate appropriate control signals to the external IC, and provide a
feedback signal back to the PHUB via the udb_ready terminal. It is up to you to determine
appropriate timing for custom mode signals.
Resources
The External Memory Interface (EMIF) is a dedicated piece of hardware in the PSoC 3 and
PSoC 5LP that is used in conjunction with UDBs to allow connection to external memory
devices.
API Memory Usage
The component memory usage varies significantly, depending on the compiler, device, number
of APIs used and component configuration. The following table provides the memory usage for
all APIs available in the given component configuration.
The measurements have been done with the associated compiler configured in Release mode
with optimization set for Size. For a specific design the map file generated by the compiler can
be analyzed to determine the memory usage.
Page 10 of 16
Document Number: 001-83032 Rev. *A
PSoC® Creator™ Component Datasheet
External Memory Interface (EMIF)
PSoC 3 (Keil_PK51)
Configuration
PSoC 5 (GCC)
PSoC 5LP (GCC)
Flash
SRAM
Flash
SRAM
Flash
SRAM
Bytes
Bytes
Bytes
Bytes
Bytes
Bytes
Asynchronous
168
2
N/A
N/A
204
5
Synchronous
185
2
N/A
N/A
236
5
Custom
154
2
N/A
N/A
188
5
DC and AC Electrical Characteristics
Specifications are valid for –40 °C ≤ TA ≤ 85 °C and TJ ≤ 100 °C, except where noted.
Specifications are valid for 1.71 V to 5.5 V, except where noted.
T (EMIF clock period) = 1/f (EMIF_clock),
where:

f (EMIF_clock) = f (BUS_CLK) if BUS_CLK <= 33MHz.

f (EMIF_clock) = 1/2*f (BUS_CLK) if 33MHz <= f(BUS_CLK) <= 66MHz.

f (EMIF_clock) = 1/3* f (BUS_CLK) if BUS_CLK frequency is >= 67MHz (PSoC 5LP only).
Document Number: 001-83032 Rev. *A
Page 11 of 16
PSoC® Creator™ Component Datasheet
External Memory Interface (EMIF)
Figure 4. Asynchronous Read Cycle Timing
Tcel
EM_CEn
Taddrv
Taddrh
EM_Addr
Address
Toel
EM_OEn
EM_WEn
Tdoesu
EM_Data
Symbol
Tdoeh
Data
Description
Conditions
Min
Typ
Max
Unit
VDDA ≥ 3.3 V
30.3
-
-
ns
2T – 5
-
2T + 5
ns
T
EMIF clock period
Tcel
EM_CEn low time
Taddrv
EM_CEn low to EM_Addr valid
-
-
5
ns
Taddrh
Address hold time after EM_WEn high
T
-
-
ns
Toel
EM_OEn low time
2T – 5
-
2T + 5
ns
Tdoesu
Data to EM_OEn high setup time
T + 15
-
-
ns
Tdoeh
Data hold time after EM_OEn high
3
-
-
ns
Page 12 of 16
Document Number: 001-83032 Rev. *A
PSoC® Creator™ Component Datasheet
External Memory Interface (EMIF)
Figure 5. Asynchronous Write Cycle Timing
Tcel
EM_CEn
Taddrv
Taddrh
EM_Addr
Address
EM_OEn
Twel
EM_WEn
Tdcev
EM_Data
Symbol
Tdweh
Data
Description
Conditions
Min
Typ
Max
Unit
VDDA ≥ 3.3 V
30.3
-
-
ns
T–5
-
T+5
ns
T
EMIF clock period
Tcel
EM_CEn low time
Taddrv
EM_CEn low to EM_Addr valid
-
-
5
ns
Taddrh
Address hold time after EM_WEn high
T
-
-
ns
Twel
EM_WEn low time
T–5
-
T+5
ns
Tdcev
EM_CEn low to data valid
-
-
7
ns
Tdweh
Data hold time after EM_WEn high
T
-
-
ns
Document Number: 001-83032 Rev. *A
Page 13 of 16
PSoC® Creator™ Component Datasheet
External Memory Interface (EMIF)
Figure 6. Synchronous Read Cycle Timing
Tcp/2
EM_Clock
Tceld
Tcehd
EM_CEn
Taddrv
Taddriv
EM_Addr
Address
Toeld
Toehd
EM_OEn
Tds
EM_Data
Data
Tadscld
Tadschd
EM_ADSCn
Symbol
Description
Conditions
Min
Typ
Max
Unit
VDDA ≥ 3.3 V
30.3
-
-
ns
T/2
-
-
ns
T
EMIF clock period
Tcp/2
EM_Clock pulse high
Tceld
EM_CEn low to EM_Clock high
5
-
-
ns
Tcehd
EM_Clock high to EM_CEn high
T/2 – 5
-
-
ns
Taddrv
EM_Addr valid to EM_Clock high
5
-
-
ns
Taddriv
EM_Clock high to EM_Addr invalid
T/2 – 5
-
-
ns
Toeld
EM_OEn low to EM_Clock high
5
-
-
ns
Toehd
EM_Clock high to EM_OEn high
T
-
-
ns
Tds
Data valid before EM_OEn high
T + 15
-
-
ns
Tadscld
EM_ADSCn low to EM_Clock high
5
-
-
ns
Tadschd
EM_Clock high to EM_ADSCn high
T/2 – 5
-
-
ns
Page 14 of 16
Document Number: 001-83032 Rev. *A
PSoC® Creator™ Component Datasheet
External Memory Interface (EMIF)
Figure 7. Synchronous Write Cycle Timing
Tcp/2
EM_Clock
Tceld
Tcehd
EM_CEn
Taddrv
Taddriv
EM_Addr
Address
Tweld
Twehd
EM_WEn
Tds
Tdh
EM_Data
Data
Tadscld
Tadschd
EM_ADSCn
Symbol
Description
Conditions
Min
Typ
Max
Unit
VDDA ≥ 3.3 V
30.3
-
-
ns
T/2
-
-
ns
T
EMIF clock period
Tcp/2
EM_Clock pulse high
Tceld
EM_CEn low to EM_Clock high
5
-
-
ns
Tcehd
EM_Clock high to EM_CEn high
T/2 – 5
-
-
ns
Taddrv
EM_Addr valid to EM_Clock high
5
-
-
ns
Taddriv
EM_Clock high to EM_Addr invalid
T/2 – 5
-
-
ns
Tweld
EM_WEn low to EM_Clock high
5
-
-
ns
Twehd
EM_Clock high to EM_WEn high
T/2 – 5
-
-
ns
Tds
Data valid before EM_Clock high
5
-
-
ns
Tdh
Data invalid after EM_Clock high
T
-
-
ns
Tadscld
EM_ADSCn low to EM_Clock high
5
-
-
ns
Tadschd
EM_Clock high to EM_ADSCn high
T/2 – 5
-
-
ns
Document Number: 001-83032 Rev. *A
Page 15 of 16
External Memory Interface (EMIF)
PSoC® Creator™ Component Datasheet
Component Changes
Version
Description of Changes
1.20.a
Minor datasheet edit.
1.20
Added update for PSoC 3/5LP
1.10 b
Updated EMIF data sheet with EMIF memory map
info
1.10
Added PSoC 5LP support
Reason for Changes / Impact
© Cypress Semiconductor Corporation, 2012-2015. The information contained herein is subject to change without notice. Cypress Semiconductor Corporation assumes no responsibility for the
use of any circuitry other than circuitry embodied in a Cypress product. Nor does it convey or imply any license under patent or other rights. Cypress products are not warranted nor intended to
be used for medical, life support, life saving, critical control or safety applications, unless pursuant to an express written agreement with Cypress. Furthermore, Cypress does not authorize its
products for use as critical components in life-support systems where a malfunction or failure may reasonably be expected to result in significant injury to the user. The inclusion of Cypress
products in life-support systems application implies that the manufacturer assumes all risk of such use and in doing so indemnifies Cypress against all charges.
CyDesigner™, Programmable System-on-Chip™, and PSoC Express™ are trademarks and PSoC® is a registered trademark of Cypress Semiconductor Corp. All other trademarks or registered
trademarks referenced herein are property of the respective corporations.
Any Source Code (software and/or firmware) is owned by Cypress Semiconductor Corporation (Cypress) and is protected by and subject to worldwide patent protection (United States and
foreign), United States copyright laws and international treaty provisions. Cypress hereby grants to licensee a personal, non-exclusive, non-transferable license to copy, use, modify, create
derivative works of, and compile the Cypress Source Code and derivative works for the sole purpose of creating custom software and or firmware in support of licensee product to be used only in
conjunction with a Cypress integrated circuit as specified in the applicable agreement. Any reproduction, modification, translation, compilation, or representation of this Source Code except as
specified above is prohibited without the express written permission of Cypress.
Disclaimer: CYPRESS MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARD TO THIS MATERIAL, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. Cypress reserves the right to make changes without further notice to the materials described herein.
Cypress does not assume any liability arising out of the application or use of any product or circuit described herein. Cypress does not authorize its products for use as critical components in lifesupport systems where a malfunction or failure may reasonably be expected to result in significant injury to the user. The inclusion of Cypress’ product in a life-support systems application
implies that the manufacturer assumes all risk of such use and in doing so indemnifies Cypress against all charges.
Use may be limited by and subject to the applicable Cypress software license agreement.
Page 16 of 16
Document Number: 001-83032 Rev. *A
Similar pages