Introduction:
Serial SRAM is a standalone volatile memory that provides an easy and inexpensive way to add more RAM to application. These are 8-pin low-power devices. They are high-performance devices have unlimited endurance and zero write times, making them ideal for applications involving continuous data transfer, buffering, data logging, audio, video, internet, graphics and other math and data-intensive functions.
These devices are available from 64 Kbit up to 1 Mbit in density and support SPI, SDI and SQI™ bus modes.
The GCBASIC library only supports SPI bus mode. The GCBASIC library supports hardware and software SPI - this is controlled via a constant, see below.
To use the SRAM libray simply include the following in your user code.
This will initialise the driver.
#define SPISRAM_CS Porta.2 'Also known as SS, or Slave Select
#define SPISRAM_SCK Portc.3 'Also known as CLK
#define SPISRAM_DO Portc.5 'Also known as MOSI
#define SPISRAM_DI Portc.4 'Also known as MISO
#define SPISRAM_HARDWARESPI
#define SPISRAM_TYPE SRAM_23LC1024SRAM memory operations.
The library exposes a set of method to support use of SRAM memory.
|
Method |
Parameters |
Usage |
|
SRAMWrite |
eepAddr as long, eepromVal as byte |
A subroutine that required the address and the value to be written to SRAM. |
|
SRAMRead |
eepAddr as long, eepromVal as byte |
A subroutine that required the address and variable to updated with the byte value from the specified SRAM address. |
|
SRAMRead |
eepAddr as long |
A function that required the address. The function returns a byte value from the specified SRAM address. |
The library requires a set of constants to support use of SRAM memory.
|
Constant |
Parameters |
Usage |
|
SPISRAM_TYPE |
Specifies the type of SRAM. |
Requires one of the following constants SRAM_23LC1024, |
|
SPISRAM_CS |
Specifies the port for the chip select port. |
Required |
|
SPISRAM_SCK |
Specifies the port for the SPI clock port. |
Required |
|
SPISRAM_DO |
Specifies the port for the SPI data out, or MOSI, port. |
Required |
|
SPISRAM_DI |
Specifies the port for the data in, or MISO, port. |
Required |
|
HWSPIMode |
Specifies the speed of the SPI communications for Hardware SPI only. |
Optional defaults to MASTERFAST. Options are MASTERSLOW, |
|
SPISRAM_HARDWARESPI |
Instructs the library to use hardware SPI, remove or comment out if you want to use software SPI. |
Optional |
The library also exposes a constant that is specific to the device.
These may be useful in the user program.
This constant is used by the library.
A user may use this public constant.
|
Constant |
Type |
Usage |
|
SPISRAM_CAPACITY |
Long value |
Use to determine the size of the SRAM device |
Examples
#include <uno_mega328p.h>
#option explicit
' USART settings
#define USART_BAUD_RATE 57600
#define USART_DELAY 0 ms
#define USART_BLOCKING
#define USART_TX_BLOCKING
'SD card attached to SPI bus as follows:
'
'UNO: MOSI - pin 11, MISO - pin 12, CLK - pin 13, CS - pin 4 (CS pin can be changed) and pin #10 (SS) must be an output
'Mega: MOSI - pin 51, MISO - pin 50, CLK - pin 52, CS - pin 4 (CS pin can be changed) and pin #52 (SS) must be an output
'Leonardo: Connect to hardware SPI via the ICSP header
#define SPISRAM_CS DIGITAL_5 'Also known as SS, or Slave Select
#define SPISRAM_SCK DIGITAL_13 'Also known as CLK
#define SPISRAM_DO DIGITAL_11 'Also known as MOSI
#define SPISRAM_DI DIGITAL_12 'Also known as MISO
#define SPISRAM_HARDWARESPI
#define SPISRAM_TYPE SRAM_23LC1024
#define HWSPIMode MASTERULTRAFAST 'MASTERSLOW | MASTER | MASTERFAST | MASTERULTRAFAST for specific AVRs only. Defaults to MASTERFAST
'********************************************************************************
'Main program
'Wait 2 seconds to open the serial terminal
wait 2 s
HSerPrintCRLF 2
HSerPrint "Writing..."
HSerPrintCRLF
For SRAM_location=0 to SPISRAM_CAPACITY - 1
SRAMWrite ( [long]SRAM_location, SRAM_location and 255 )
Next
dim spirambyteread as Byte
spirambyteread = 11
HSerPrintCRLF 2
dim SRAM_location as long
HSerPrint "Reading..."
HSerPrintCRLF
For SRAM_location=0 to SPISRAM_CAPACITY - 1
'choose one....
'SRAMread ( SRAM_location, spirambyteread )
'or, as a function
spirambyteread = SRAMread ( SRAM_location )
if spirambyteread = ( SRAM_location and 255 ) then
HSerPrint hex(spirambyteread)
else
HSerPrint "**"
end if
HSerPrint ":"
Next
HSerPrintCRLF
HSerPrint "Wait..."
HSerPrintCRLF
Wait 2 s
HSerPrint "Rewriting to 0x00 ..."
HSerPrintCRLF
For SRAM_location=0 to SPISRAM_CAPACITY - 1
SRAMWrite ( [long]SRAM_location, 0 )
Next
Dim errorcount as long
errorcount = 0
For SRAM_location=0 to SPISRAM_CAPACITY - 1
SRAMRead ( SRAM_location, spirambyteread )
if spirambyteread <> 0 then
errorcount++
end if
Next
HSerPrint "Error Count (should be 0) = "
HSerPrint errorcount
HSerPrintCRLF
HSerPrint "End..."
HSerPrintCRLF
endor, for a PIC with PPS
/*
An example program for GCGB and GCB.
------------------------------------------------------------------------
This program blinks the onboard LED of a microcontroller - simple - the demonstration should work across many microcontrollers.
This sample file can be adapted to any of the supported microcontrollers by simply changing the #chip definition - do this by changing to your chip. Other common chips are shown.
To make your programmer or your bootloader work, simply do the following.
From within this IDE, press function_key F4, then select 'Edit Programmer Preferences'. This will show you the 'Programmer Preferences', select the 'Programmer' tab.
For PIC: Typically, if you are using a PICKIT2 then select 'Microchip PICKit 2 CLI - Default' will work for you - select and drag this to the top of the dialog area.
For AVR: Typically, for an UNO the programmer 'Arduino UNO/328p@115200' will work, select the option from the list of programmers, then, select 'Edit',
please edit the communication 'Port', select 'OK', and, then select this option again and drag this to the top of the dialog area.
For further adventures with GCBASIC .... Select F4 and then "view Demos" for 1000's of sample programs.
Enjoy.
*/
// ************************************************************************
'Chip Settings.
#chip 18F47k42, 64
#config MCLRE = ON
#option explicit
'PPS Tool version: 0.0.5.27
'PinManager data: v1.78
'Generated for 18F47K42
'
'Template comment at the start of the config file
'
#startup InitPPS, 85
#define PPSToolPart 18F47K42
Sub InitPPS
'This has been added to turn off PPS SPI when in SPI software mode
#ifdef SPISRAM_HARDWARESPI
'Module: SPI1
RC3PPS = 0x001E 'SCK1 > RC3
SPI1SCKPPS = 0x0013 'RC3 > SCK1 (bi-directional)
RC5PPS = 0x001F 'SDO1 > RC5
SPI1SDIPPS = 0x0014 'RC4 > SDI1
'Module: UART pin directions
#endif
'Module: UART pin directions
Dir PORTC.6 Out ' Make TX1 pin an output
'Module: UART1
RC6PPS = 0x0013 'TX1 > RC6
End Sub
'Template comment at the end of the config file
' USART settings
#define USART_BAUD_RATE 57600
#define USART_DELAY 0 ms
#define USART_BLOCKING
#define USART_TX_BLOCKING
#define SPISRAM_CS Porta.2 'Also known as SS, or Slave Select
#define SPISRAM_SCK Portc.3 'Also known as CLK
#define SPISRAM_DO Portc.5 'Also known as MOSI
#define SPISRAM_DI Portc.4 'Also known as MISO
#define SPISRAM_HARDWARESPI
#define SPISRAM_TYPE SRAM_23LC1024
'********************************************************************************
'Main program
'Wait 2 seconds to open the serial terminal
wait 2 s
dim sizeofSPIRAM as long
sizeofSPIRAM = SPISRAM_CAPACITY
HSerPrintCRLF 2
HSerPrint "Writing...SPISRAM_CAPACITY = 0x"
HSerPrint LongTohex(sizeofSPIRAM)
HSerPrintCRLF
wait 100 ms
dim SRAM_location as long
For SRAM_location=0 to SPISRAM_CAPACITY - 1
SRAMWrite ( [long]SRAM_location, SRAM_location and 255 )
Next
dim spirambyteread as Byte
spirambyteread = 11 'could be any number....
HSerPrintCRLF 2
HSerPrint "Reading..."
HSerPrintCRLF
For SRAM_location=0 to SPISRAM_CAPACITY - 1
'choose one....
'SRAMRead ( SRAM_location, spirambyteread )
'or, as a function
spirambyteread = SRAMRead ( SRAM_location )
if spirambyteread = ( SRAM_location and 255 ) then
HSerPrint hex(spirambyteread)
else
HSerPrint "**"
end if
HSerPrint ":"
Next
HSerPrintCRLF
HSerPrint "Wait..."
HSerPrintCRLF
Wait 2 s
HSerPrint "Rewriting to 0x00 ..."
HSerPrintCRLF
For SRAM_location=0 to SPISRAM_CAPACITY - 1
SRAMWrite ( [long]SRAM_location, 0 )
Next
Dim errorcount as long
errorcount = 0
For SRAM_location=0 to SPISRAM_CAPACITY - 1
SRAMRead ( SRAM_location, spirambyteread )
if spirambyteread <> 0 then
errorcount++
end if
Next
HSerPrint "Error Count (should be 0) = "
HSerPrint errorcount
HSerPrintCRLF
HSerPrint "End..."
HSerPrintCRLF
do
loop
