93 lines
2.5 KiB
C
93 lines
2.5 KiB
C
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// spiram.c
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//
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// Little library for accessing SPI RAM such as 23K256-I/P
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// using bcm2835 library on Raspberry Pi
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//
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// Author: Mike McCauley
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// Copyright (C) 2018 Mike McCauley
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// This software is part of the bcm2835 library and is licensed under the same conditions
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// $Id: $
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#include <bcm2835.h>
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#include <string.h> // memcpy
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#include "spiram.h"
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static uint8_t _mode = SPIRAM_MODE_INVALID;
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uint8_t spiram_read_sr()
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{
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uint8_t command[] = { SPIRAM_OPCODE_READ_SR, 0};
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bcm2835_spi_transfern(command, sizeof(command));
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return command[1];
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}
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bool spiram_write_sr(uint8_t value)
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{
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uint8_t command[] = { SPIRAM_OPCODE_WRITE_SR, value};
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bcm2835_spi_transfern(command, sizeof(command));
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return true;
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}
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bool spiram_set_mode(uint8_t mode)
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{
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if (mode != _mode)
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{
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spiram_write_sr(mode);
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_mode = mode;
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}
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return true;
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}
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bool spiram_begin()
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{
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_mode = SPIRAM_MODE_BYTE;
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bcm2835_spi_setBitOrder(BCM2835_SPI_BIT_ORDER_MSBFIRST); // The default
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bcm2835_spi_setDataMode(BCM2835_SPI_MODE0); // The default
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bcm2835_spi_setClockDivider(BCM2835_SPI_CLOCK_DIVIDER_65536); // The default
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bcm2835_spi_chipSelect(BCM2835_SPI_CS0); // The default
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bcm2835_spi_setChipSelectPolarity(BCM2835_SPI_CS0, LOW); // the default
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return true;
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}
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bool spiram_end()
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{
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bcm2835_spi_end();
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return true;
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}
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uint8_t spiram_read_byte(uint16_t address)
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{
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spiram_set_mode(SPIRAM_MODE_BYTE);
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uint8_t command[] = { SPIRAM_OPCODE_READ, (address >> 8) & 0xff, address & 0xff, 0xff };
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bcm2835_spi_transfern(command, sizeof(command));
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uint8_t ret = command[3];
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}
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bool spiram_write_byte(uint16_t address, uint8_t value)
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{
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spiram_set_mode(SPIRAM_MODE_BYTE);
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uint8_t command[] = { SPIRAM_OPCODE_WRITE, (address >> 8) & 0xff, address & 0xff, value };
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bcm2835_spi_writenb(command, sizeof(command));
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return true;
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}
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bool spiram_read_page(uint16_t address, uint8_t *buf)
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{
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spiram_set_mode(SPIRAM_MODE_PAGE);
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uint8_t command[3 + SPIRAM_PAGE_SIZE] = { SPIRAM_OPCODE_READ, (address >> 8) & 0xff, address & 0xff };
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bcm2835_spi_transfern(command, sizeof(command));
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memcpy(buf, command + 3, SPIRAM_PAGE_SIZE);
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return true;
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}
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bool spiram_write_page(uint16_t address, uint8_t *buf)
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{
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spiram_set_mode(SPIRAM_MODE_PAGE);
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uint8_t command[3 + SPIRAM_PAGE_SIZE] = { SPIRAM_OPCODE_WRITE, (address >> 8) & 0xff, address & 0xff };
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memcpy(command + 3, buf, SPIRAM_PAGE_SIZE);;
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bcm2835_spi_writenb(command, sizeof(command));
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return true;
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}
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