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Merge pull request #12446 from boomer41/i2cee-add-eight-bit-address
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Add Eight-Bit-Addressing mode to I2CEEBlockDevice.
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@0xc0170
0xc0170 authored Feb 21, 2020
2 parents c520449 + 440fa49 commit a18259a
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Showing 2 changed files with 82 additions and 34 deletions.
67 changes: 48 additions & 19 deletions components/storage/blockdevice/COMPONENT_I2CEE/I2CEEBlockDevice.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -22,17 +22,21 @@ using namespace mbed;

I2CEEBlockDevice::I2CEEBlockDevice(
PinName sda, PinName scl, uint8_t addr,
bd_size_t size, bd_size_t block, int freq)
: _i2c_addr(addr), _size(size), _block(block)
bd_size_t size, bd_size_t block, int freq,
bool address_is_eight_bit)
: _i2c_addr(addr), _size(size), _block(block),
_address_is_eight_bit(address_is_eight_bit)
{
_i2c = new (_i2c_buffer) I2C(sda, scl);
_i2c->frequency(freq);
}

I2CEEBlockDevice::I2CEEBlockDevice(
I2C *i2c_obj, uint8_t addr,
bd_size_t size, bd_size_t block)
: _i2c_addr(addr), _size(size), _block(block)
bd_size_t size, bd_size_t block,
bool address_is_eight_bit)
: _i2c_addr(addr), _size(size), _block(block),
_address_is_eight_bit(address_is_eight_bit)
{
_i2c = i2c_obj;
}
Expand All @@ -58,48 +62,61 @@ int I2CEEBlockDevice::read(void *buffer, bd_addr_t addr, bd_size_t size)
// Check the address and size fit onto the chip.
MBED_ASSERT(is_valid_read(addr, size));

auto *pBuffer = static_cast<char *>(buffer);

_i2c->start();

if (!_i2c->write(_i2c_addr | 0) ||
!_i2c->write((char)(addr >> 8)) ||
!_i2c->write((char)(addr & 0xff))) {
if (1 != _i2c->write(get_paged_device_address(addr))) {
return BD_ERROR_DEVICE_ERROR;
}

_i2c->stop();
if (!_address_is_eight_bit && 1 != _i2c->write((char)(addr >> 8u))) {
return BD_ERROR_DEVICE_ERROR;
}

auto err = _sync();
if (err) {
return err;
if (1 != _i2c->write((char)(addr & 0xffu))) {
return BD_ERROR_DEVICE_ERROR;
}

if (0 != _i2c->read(_i2c_addr, static_cast<char *>(buffer), size)) {
_i2c->stop();

if (0 != _i2c->read(_i2c_addr, pBuffer, size)) {
return BD_ERROR_DEVICE_ERROR;
}

return 0;
return BD_ERROR_OK;
}

int I2CEEBlockDevice::program(const void *buffer, bd_addr_t addr, bd_size_t size)
{
// Check the addr and size fit onto the chip.
MBED_ASSERT(is_valid_program(addr, size));

const auto *pBuffer = static_cast<const char *>(buffer);

// While we have some more data to write.
while (size > 0) {
uint32_t off = addr % _block;
uint32_t chunk = (off + size < _block) ? size : (_block - off);

_i2c->start();

if (!_i2c->write(_i2c_addr | 0) ||
!_i2c->write((char)(addr >> 8)) ||
!_i2c->write((char)(addr & 0xff))) {
if (1 != _i2c->write(get_paged_device_address(addr))) {
return BD_ERROR_DEVICE_ERROR;
}

if (!_address_is_eight_bit && 1 != _i2c->write((char)(addr >> 8u))) {
return BD_ERROR_DEVICE_ERROR;
}

if (1 != _i2c->write((char)(addr & 0xffu))) {
return BD_ERROR_DEVICE_ERROR;
}

for (unsigned i = 0; i < chunk; i++) {
_i2c->write(static_cast<const char *>(buffer)[i]);
if (1 != _i2c->write(pBuffer[i])) {
return BD_ERROR_DEVICE_ERROR;
}
}

_i2c->stop();
Expand All @@ -112,10 +129,10 @@ int I2CEEBlockDevice::program(const void *buffer, bd_addr_t addr, bd_size_t size

addr += chunk;
size -= chunk;
buffer = static_cast<const char *>(buffer) + chunk;
pBuffer += chunk;
}

return 0;
return BD_ERROR_OK;
}

int I2CEEBlockDevice::erase(bd_addr_t addr, bd_size_t size)
Expand Down Expand Up @@ -164,3 +181,15 @@ const char *I2CEEBlockDevice::get_type() const
{
return "I2CEE";
}

uint8_t I2CEEBlockDevice::get_paged_device_address(bd_addr_t address)
{
if (!_address_is_eight_bit) {
return _i2c_addr;
} else {
// Use the three least significant bits of the 2nd byte as the page
// The page will be bits 2-4 of the user defined addresses.
return _i2c_addr | ((address & 0x0700u) >> 7u);
}
}

49 changes: 34 additions & 15 deletions components/storage/blockdevice/COMPONENT_I2CEE/I2CEEBlockDevice.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -59,29 +59,37 @@ class I2CEEBlockDevice : public BlockDevice {
public:
/** Constructor to create an I2CEEBlockDevice on I2C pins
*
* @param sda The pin name for the sda line of the I2C bus.
* @param scl The pin name for the scl line of the I2C bus.
* @param addr The 8bit I2C address of the chip, common range 0xa0 - 0xae.
* @param size The size of the device in bytes
* @param block The page size of the device in bytes, defaults to 32bytes
* @param freq The frequency of the I2C bus, defaults to 400K.
* @param sda The pin name for the sda line of the I2C bus.
* @param scl The pin name for the scl line of the I2C bus.
* @param addr The 8bit I2C address of the chip, common range 0xa0 - 0xae.
* @param size The size of the device in bytes
* @param block The page size of the device in bytes, defaults to 32bytes
* @param freq The frequency of the I2C bus, defaults to 400K.
* @param address_is_eight_bit Specifies whether the EEPROM device is using eight bit
* addresses instead of 16 bit addresses. This is used for example
* in AT24C series chips.
*/
I2CEEBlockDevice(
PinName sda, PinName scl, uint8_t address,
bd_size_t size, bd_size_t block = 32,
int bus_speed = 400000);
int bus_speed = 400000,
bool address_is_eight_bit = false);

/** Constructor to create an I2CEEBlockDevice on I2C pins
*
* @param i2c The I2C instance pointer
* @param addr The 8bit I2C address of the chip, common range 0xa0 - 0xae.
* @param size The size of the device in bytes
* @param block The page size of the device in bytes, defaults to 32bytes
* @param freq The frequency of the I2C bus, defaults to 400K.
*/
*
* @param i2c The I2C instance pointer
* @param addr The 8bit I2C address of the chip, common range 0xa0 - 0xae.
* @param size The size of the device in bytes
* @param block The page size of the device in bytes, defaults to 32bytes
* @param freq The frequency of the I2C bus, defaults to 400K.
* @param address_is_eight_bit Specifies whether the EEPROM device is using eight bit
* addresses instead of 16 bit addresses. This is used for example
* in AT24C series chips.
*/
I2CEEBlockDevice(
mbed::I2C *i2c_obj, uint8_t address,
bd_size_t size, bd_size_t block = 32);
bd_size_t size, bd_size_t block = 32,
bool address_is_eight_bit = false);

/** Destructor of I2CEEBlockDevice
*/
Expand Down Expand Up @@ -166,10 +174,21 @@ class I2CEEBlockDevice : public BlockDevice {
mbed::I2C *_i2c;
uint32_t _i2c_buffer[sizeof(mbed::I2C) / sizeof(uint32_t)];
uint8_t _i2c_addr;
bool _address_is_eight_bit;
uint32_t _size;
uint32_t _block;

int _sync();

/**
* Gets the device's I2C address with respect to the requested page.
* When eight-bit mode is disabled, this function is a noop.
* When eight-bit mode is enabled, it sets the bits required
* in the devices address. Other bits remain unchanged.
* @param address An address in the requested page.
* @return The device's I2C address for that page
*/
uint8_t get_paged_device_address(bd_addr_t address);
};


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