Diff: Ser23K256.h

Revision:

3:d2314b1ac797

Parent:

2:f96c3c85aa3b

--- a/Ser23K256.h	Sun Aug 15 13:06:52 2010 +0000
+++ b/Ser23K256.h	Sun Aug 15 14:28:05 2010 +0000
@@ -1,6 +1,15 @@
-// Ser23K256 - drive the Microchip 23K256 SRAM using SPI
-// Copyright (c) 2010 Romilly Cocking
-// Released under the MIT License: http://mbed.org/license/mit
+/** Ser23K256 - drive the Microchip 23K256 SRAM using SPI
+* Copyright (c) 2010 Romilly Cocking
+* Released under the MIT License: http://mbed.org/license/mit
+*
+* 23K256 data sheet at http://ww1.microchip.com/downloads/en/DeviceDoc/22100B.pdf
+*
+* Page-mode commands have not been implemented; I have found no need for them yet.
+*
+* Assumes spi mode is default (8,0).
+*
+* You can clock the 23K256 at up to 20MHz, so it supports the mbed's maximum SPI frequency of 12MHz.
+*/
 
 #include "mbed.h"
 
@@ -17,12 +26,74 @@
 #define READ_STATUS     0x05 // called RDSR in datasheet
 #define WRITE_STATUS    0x01 // called WRSR in datasheet
 
+/** An interface for the Microchip 32k byte 23K256 SRAM over SPI
+*
+* 
+*
+* @code
+* #include "mbed.h"
+* #include "Ser23K256.h"
+*
+*
+* SPI spi(p5,p6,p7);
+* Ser23K256 sram(spi,p14);
+*
+* int main() {
+*   char buff[50];
+*   sram.write(0, 'h');
+*   sram.write(1, 'i');
+*   sram.write(2, '!');
+*   sram.write(3, '\0');
+*   for (int address = 0; address < 4; address++) {
+*       buff[address] = sram.read(address);
+*   }
+*   printf("sram = %s\r\n", buff);
+*   sram.write(0, "Hello world!",12);
+*   sram.read(0, buff, 12);
+*   buff[12]='\0';
+*   printf("now = %s\r\n", buff);
+*}
+* @endcode
+* connections:
+* chip pin 1 to mbed ncs (see below)
+* chip pin 2 SO to mbed MISO
+* chip pin 3 - no connection
+* chip pin 4 to mbed Gnd
+* chip pin 5 SI pin to mbed MOSI
+* chip pin 6 SCK to mbed sck 
+* chip pin 7 (notHOLD) to mbed Vout
+* chip pin 8 to mbed Vout
+*/
 class Ser23K256 {
 public:
+/** Create an interface
+*
+*
+* @param spi   An SPI object
+* @param ncs   Not chip select pin - any free Digital pin will do
+*/
     Ser23K256(SPI& spi, PinName ncs);
+/** read a byte from SRAM
+* @param address    The address to read from
+* @return the character at that address
+*/
     char read(int address);
+/** read multiple bytes from SRAM into a buffer
+* @param address    The SRAM address to read from
+* @param buffer     The buffer to read into (must be big enough!)
+* @param count      The number of bytes to read
+*/
     void read(int address, char * buffer, int count);
+/** write a byte to SRAM
+* @param address    The address SRAM to write to
+* @param byte       The byte to write there
+*/
     void write(int address, char byte);
+    /** write multiple bytes to SRAM from a buffer
+* @param address    The SRAM address write to
+* @param buffer     The buffer to write from
+* @param count      The number of bytes to write
+*/
     void write(int address, char * buffer, int count);
 private:
     SPI& _spi;