EmbeddedArtists AB / Mbed 2 deprecated lpc812_exp_solution_spi-e2prom

Solutions for the SPI E2PROM experiments for LPC812 MAX

Dependencies:   mbed

SPI25LC080.cpp@1:819f21483c01, 2013-11-28 (annotated)

Committer:
embeddedartists
Date:
Thu Nov 28 12:17:45 2013 +0000
Revision:
1:819f21483c01
Parent:
SPI24LC080.cpp@0:aa38ad0bf51d 
Renamed the SPI24LC080 class to SPI25LC080 as it is an interface to the 25LC080 chip.

Who changed what in which revision?

UserRevisionLine numberNew contents of line
embeddedartists 0:aa38ad0bf51d 1 #include "mbed.h"
embeddedartists 1:819f21483c01 2 #include "SPI25LC080.h"
embeddedartists 0:aa38ad0bf51d 3
embeddedartists 0:aa38ad0bf51d 4 /* SPI E2PROM command set */
embeddedartists 0:aa38ad0bf51d 5 #define INST_WREN 0x06 /* MSB A8 is set to 0, simplifying test */
embeddedartists 0:aa38ad0bf51d 6 #define INST_WRDI 0x04
embeddedartists 0:aa38ad0bf51d 7 #define INST_RDSR 0x05
embeddedartists 0:aa38ad0bf51d 8 #define INST_WRSR 0x01
embeddedartists 0:aa38ad0bf51d 9 #define INST_READ 0x03
embeddedartists 0:aa38ad0bf51d 10 #define INST_WRITE 0x02
embeddedartists 0:aa38ad0bf51d 11
embeddedartists 0:aa38ad0bf51d 12 /* RDSR status bit definition */
embeddedartists 0:aa38ad0bf51d 13 #define RDSR_RDY 0x01
embeddedartists 0:aa38ad0bf51d 14 #define RDSR_WEN 0x02
embeddedartists 0:aa38ad0bf51d 15
embeddedartists 0:aa38ad0bf51d 16 /* Page size of E2PROM */
embeddedartists 0:aa38ad0bf51d 17 #define PAGE_SIZE 16
embeddedartists 0:aa38ad0bf51d 18
embeddedartists 0:aa38ad0bf51d 19 #define LOCAL_MIN(__a, __b) ( ((__a) < (__b)) ? (__a) : (__b) )
embeddedartists 0:aa38ad0bf51d 20
embeddedartists 1:819f21483c01 21 SPI25LC080::SPI25LC080(PinName mosi, PinName sclk, PinName miso, PinName ssel) :
embeddedartists 0:aa38ad0bf51d 22 m_spi(mosi, miso, sclk), m_ssel(ssel)
embeddedartists 0:aa38ad0bf51d 23 {
embeddedartists 0:aa38ad0bf51d 24 }
embeddedartists 0:aa38ad0bf51d 25
embeddedartists 1:819f21483c01 26 void SPI25LC080::read(uint16_t address, uint8_t* pData, uint32_t length)
embeddedartists 0:aa38ad0bf51d 27 {
embeddedartists 0:aa38ad0bf51d 28 //pull SSEL/CS low
embeddedartists 0:aa38ad0bf51d 29 m_ssel = 0;
embeddedartists 0:aa38ad0bf51d 30
embeddedartists 0:aa38ad0bf51d 31 //output read command and address
embeddedartists 0:aa38ad0bf51d 32 m_spi.write(INST_READ);
embeddedartists 0:aa38ad0bf51d 33 m_spi.write((address >> 8) & 0xff);
embeddedartists 0:aa38ad0bf51d 34 m_spi.write(address & 0xff);
embeddedartists 0:aa38ad0bf51d 35
embeddedartists 0:aa38ad0bf51d 36 //read bytes from E2PROM
embeddedartists 0:aa38ad0bf51d 37 for (uint32_t i = 0; i < length; i++) {
embeddedartists 0:aa38ad0bf51d 38 pData[i] = m_spi.write(0x00); // write dummy byte to get read next value
embeddedartists 0:aa38ad0bf51d 39 }
embeddedartists 0:aa38ad0bf51d 40
embeddedartists 0:aa38ad0bf51d 41 //pull SSEL/CS high
embeddedartists 0:aa38ad0bf51d 42 m_ssel = 1;
embeddedartists 0:aa38ad0bf51d 43 }
embeddedartists 0:aa38ad0bf51d 44
embeddedartists 1:819f21483c01 45 uint8_t SPI25LC080::status()
embeddedartists 0:aa38ad0bf51d 46 {
embeddedartists 0:aa38ad0bf51d 47 //pull SSEL/CS low
embeddedartists 0:aa38ad0bf51d 48 m_ssel = 0;
embeddedartists 0:aa38ad0bf51d 49
embeddedartists 0:aa38ad0bf51d 50 uint8_t status = m_spi.write(INST_RDSR);
embeddedartists 0:aa38ad0bf51d 51
embeddedartists 0:aa38ad0bf51d 52 //pull SSEL/CS high
embeddedartists 0:aa38ad0bf51d 53 m_ssel = 1;
embeddedartists 0:aa38ad0bf51d 54
embeddedartists 0:aa38ad0bf51d 55 return status;
embeddedartists 0:aa38ad0bf51d 56 }
embeddedartists 0:aa38ad0bf51d 57
embeddedartists 1:819f21483c01 58 void SPI25LC080::write_enable()
embeddedartists 0:aa38ad0bf51d 59 {
embeddedartists 0:aa38ad0bf51d 60 //pull SSEL/CS low
embeddedartists 0:aa38ad0bf51d 61 m_ssel = 0;
embeddedartists 0:aa38ad0bf51d 62
embeddedartists 0:aa38ad0bf51d 63 //output write command and address
embeddedartists 0:aa38ad0bf51d 64 m_spi.write(INST_WREN);
embeddedartists 0:aa38ad0bf51d 65
embeddedartists 0:aa38ad0bf51d 66 //pull SSEL/CS high
embeddedartists 0:aa38ad0bf51d 67 m_ssel = 1;
embeddedartists 0:aa38ad0bf51d 68 }
embeddedartists 0:aa38ad0bf51d 69
embeddedartists 1:819f21483c01 70 void SPI25LC080::write(uint16_t address, uint8_t* pData, uint32_t length)
embeddedartists 0:aa38ad0bf51d 71 {
embeddedartists 0:aa38ad0bf51d 72 uint32_t left = length;
embeddedartists 0:aa38ad0bf51d 73 uint32_t offset = address;
embeddedartists 0:aa38ad0bf51d 74 uint32_t len = 0;
embeddedartists 0:aa38ad0bf51d 75
embeddedartists 0:aa38ad0bf51d 76 // find length of first page write
embeddedartists 0:aa38ad0bf51d 77 if ((address / PAGE_SIZE) != ((address + length) / PAGE_SIZE)) {
embeddedartists 0:aa38ad0bf51d 78 //spans across at least one boundary
embeddedartists 0:aa38ad0bf51d 79 len = PAGE_SIZE - (address % PAGE_SIZE);
embeddedartists 0:aa38ad0bf51d 80 } else {
embeddedartists 0:aa38ad0bf51d 81 // ends inside same page => use normal length
embeddedartists 0:aa38ad0bf51d 82 len = length % PAGE_SIZE;
embeddedartists 0:aa38ad0bf51d 83 }
embeddedartists 0:aa38ad0bf51d 84
embeddedartists 0:aa38ad0bf51d 85 //insert code here to break up large write operation into several
embeddedartists 0:aa38ad0bf51d 86 //page write operations (16 or 32 byte pages)
embeddedartists 0:aa38ad0bf51d 87 while (left > 0) {
embeddedartists 0:aa38ad0bf51d 88
embeddedartists 0:aa38ad0bf51d 89 //Enable write latch
embeddedartists 0:aa38ad0bf51d 90 write_enable();
embeddedartists 0:aa38ad0bf51d 91
embeddedartists 0:aa38ad0bf51d 92 //pull SSEL/CS low
embeddedartists 1:819f21483c01 93 m_ssel = 0;
embeddedartists 0:aa38ad0bf51d 94
embeddedartists 0:aa38ad0bf51d 95 //output write command and address
embeddedartists 0:aa38ad0bf51d 96 m_spi.write(INST_WRITE);
embeddedartists 0:aa38ad0bf51d 97 m_spi.write((offset >> 8) & 0xff);
embeddedartists 0:aa38ad0bf51d 98 m_spi.write(offset & 0xff);
embeddedartists 0:aa38ad0bf51d 99
embeddedartists 0:aa38ad0bf51d 100 //send bytes to write E2PROM
embeddedartists 0:aa38ad0bf51d 101 for (uint32_t i = 0; i < len; i++) {
embeddedartists 0:aa38ad0bf51d 102 m_spi.write(pData[offset + i]);
embeddedartists 0:aa38ad0bf51d 103 }
embeddedartists 0:aa38ad0bf51d 104
embeddedartists 0:aa38ad0bf51d 105 //pull SSEL/CS high
embeddedartists 1:819f21483c01 106 m_ssel = 1;
embeddedartists 0:aa38ad0bf51d 107
embeddedartists 0:aa38ad0bf51d 108 offset += len;
embeddedartists 0:aa38ad0bf51d 109 left -= len;
embeddedartists 0:aa38ad0bf51d 110 len = LOCAL_MIN(left, PAGE_SIZE);
embeddedartists 0:aa38ad0bf51d 111
embeddedartists 0:aa38ad0bf51d 112 //wait until write operations is done
embeddedartists 0:aa38ad0bf51d 113 //for now, just wait. A more sophisticated method is to poll the status register
embeddedartists 0:aa38ad0bf51d 114 wait_ms(5);
embeddedartists 0:aa38ad0bf51d 115 }
embeddedartists 0:aa38ad0bf51d 116 }
embeddedartists 0:aa38ad0bf51d 117