marcel van de Kamp
Dependents: Internal_ADC_with_interrupt
Ser23K256.cpp@0:d049f6422506, 2011-03-04 (annotated)
- Committer:
- marcelvandekamp
- Date:
- Fri Mar 04 15:22:24 2011 +0000
- Revision:
- 0:d049f6422506
Who changed what in which revision?
| User | Revision | Line number | New contents of line |
|---|---|---|---|
| marcelvandekamp | 0:d049f6422506 | 1 | /* Ser23K256 - drive the Microchip 23K256 SRAM using SPI |
| marcelvandekamp | 0:d049f6422506 | 2 | * Copyright (c) 2010 Romilly Cocking |
| marcelvandekamp | 0:d049f6422506 | 3 | * Released under the MIT License: http://mbed.org/license/mit |
| marcelvandekamp | 0:d049f6422506 | 4 | */ |
| marcelvandekamp | 0:d049f6422506 | 5 | |
| marcelvandekamp | 0:d049f6422506 | 6 | #include "mbed.h" |
| marcelvandekamp | 0:d049f6422506 | 7 | #include "Ser23K256.h" |
| marcelvandekamp | 0:d049f6422506 | 8 | |
| marcelvandekamp | 0:d049f6422506 | 9 | Ser23K256::Ser23K256(SPI& spi, PinName ncs) : _spi(spi), _ncs(ncs) { |
| marcelvandekamp | 0:d049f6422506 | 10 | deselect(); |
| marcelvandekamp | 0:d049f6422506 | 11 | } |
| marcelvandekamp | 0:d049f6422506 | 12 | |
| marcelvandekamp | 0:d049f6422506 | 13 | void Ser23K256::select() { |
| marcelvandekamp | 0:d049f6422506 | 14 | _ncs = 0; |
| marcelvandekamp | 0:d049f6422506 | 15 | } |
| marcelvandekamp | 0:d049f6422506 | 16 | |
| marcelvandekamp | 0:d049f6422506 | 17 | void Ser23K256::deselect() { |
| marcelvandekamp | 0:d049f6422506 | 18 | _ncs = 1; |
| marcelvandekamp | 0:d049f6422506 | 19 | } |
| marcelvandekamp | 0:d049f6422506 | 20 | |
| marcelvandekamp | 0:d049f6422506 | 21 | void Ser23K256::writeStatus(char status) { |
| marcelvandekamp | 0:d049f6422506 | 22 | select(); |
| marcelvandekamp | 0:d049f6422506 | 23 | _spi.write(WRITE_STATUS); |
| marcelvandekamp | 0:d049f6422506 | 24 | _spi.write(status); |
| marcelvandekamp | 0:d049f6422506 | 25 | deselect(); |
| marcelvandekamp | 0:d049f6422506 | 26 | } |
| marcelvandekamp | 0:d049f6422506 | 27 | |
| marcelvandekamp | 0:d049f6422506 | 28 | char Ser23K256::readStatus() { |
| marcelvandekamp | 0:d049f6422506 | 29 | select(); |
| marcelvandekamp | 0:d049f6422506 | 30 | _spi.write(READ_STATUS); |
| marcelvandekamp | 0:d049f6422506 | 31 | char result = (char) _spi.write(0); |
| marcelvandekamp | 0:d049f6422506 | 32 | deselect(); |
| marcelvandekamp | 0:d049f6422506 | 33 | return result; |
| marcelvandekamp | 0:d049f6422506 | 34 | } |
| marcelvandekamp | 0:d049f6422506 | 35 | |
| marcelvandekamp | 0:d049f6422506 | 36 | void Ser23K256::prepareCommand(char command, int address) { |
| marcelvandekamp | 0:d049f6422506 | 37 | select(); |
| marcelvandekamp | 0:d049f6422506 | 38 | _spi.write(command); |
| marcelvandekamp | 0:d049f6422506 | 39 | _spi.write(address >> 8); |
| marcelvandekamp | 0:d049f6422506 | 40 | _spi.write(address & 0xFF); |
| marcelvandekamp | 0:d049f6422506 | 41 | } |
| marcelvandekamp | 0:d049f6422506 | 42 | |
| marcelvandekamp | 0:d049f6422506 | 43 | // write or read a single byte |
| marcelvandekamp | 0:d049f6422506 | 44 | |
| marcelvandekamp | 0:d049f6422506 | 45 | void Ser23K256::write(int address, char byte) { |
| marcelvandekamp | 0:d049f6422506 | 46 | prepareCommand(WRITE, address); |
| marcelvandekamp | 0:d049f6422506 | 47 | _spi.write(byte); |
| marcelvandekamp | 0:d049f6422506 | 48 | deselect(); |
| marcelvandekamp | 0:d049f6422506 | 49 | } |
| marcelvandekamp | 0:d049f6422506 | 50 | |
| marcelvandekamp | 0:d049f6422506 | 51 | char Ser23K256::read(int address) { |
| marcelvandekamp | 0:d049f6422506 | 52 | prepareCommand(READ, address); |
| marcelvandekamp | 0:d049f6422506 | 53 | int result = _spi.write(0); |
| marcelvandekamp | 0:d049f6422506 | 54 | deselect(); |
| marcelvandekamp | 0:d049f6422506 | 55 | return (char) result; |
| marcelvandekamp | 0:d049f6422506 | 56 | } |
| marcelvandekamp | 0:d049f6422506 | 57 | |
| marcelvandekamp | 0:d049f6422506 | 58 | // buffered write and read |
| marcelvandekamp | 0:d049f6422506 | 59 | |
| marcelvandekamp | 0:d049f6422506 | 60 | /* |
| marcelvandekamp | 0:d049f6422506 | 61 | * the single-byte read and write assume the 23K256 is in its default byte-mode |
| marcelvandekamp | 0:d049f6422506 | 62 | * so sequential-model commands must switch the chip into sequential mode |
| marcelvandekamp | 0:d049f6422506 | 63 | * at the start and return it to byte mode at the end. |
| marcelvandekamp | 0:d049f6422506 | 64 | */ |
| marcelvandekamp | 0:d049f6422506 | 65 | |
| marcelvandekamp | 0:d049f6422506 | 66 | void Ser23K256::write(int address, char * buffer, int count) { |
| marcelvandekamp | 0:d049f6422506 | 67 | writeStatus(SEQUENTIAL_MODE); |
| marcelvandekamp | 0:d049f6422506 | 68 | prepareCommand(WRITE, address); |
| marcelvandekamp | 0:d049f6422506 | 69 | for (int i = 0; i < count; i++) { |
| marcelvandekamp | 0:d049f6422506 | 70 | _spi.write(buffer[i]); |
| marcelvandekamp | 0:d049f6422506 | 71 | } |
| marcelvandekamp | 0:d049f6422506 | 72 | deselect(); |
| marcelvandekamp | 0:d049f6422506 | 73 | writeStatus(BYTE_MODE); |
| marcelvandekamp | 0:d049f6422506 | 74 | } |
| marcelvandekamp | 0:d049f6422506 | 75 | |
| marcelvandekamp | 0:d049f6422506 | 76 | void Ser23K256::read(int address, char * buffer, int count) { |
| marcelvandekamp | 0:d049f6422506 | 77 | writeStatus(SEQUENTIAL_MODE); |
| marcelvandekamp | 0:d049f6422506 | 78 | prepareCommand(READ, address); |
| marcelvandekamp | 0:d049f6422506 | 79 | for (int i = 0; i < count; i++) { |
| marcelvandekamp | 0:d049f6422506 | 80 | buffer[i] = _spi.write(0); |
| marcelvandekamp | 0:d049f6422506 | 81 | } |
| marcelvandekamp | 0:d049f6422506 | 82 | deselect(); |
| marcelvandekamp | 0:d049f6422506 | 83 | writeStatus(BYTE_MODE); |
| marcelvandekamp | 0:d049f6422506 | 84 | } |