SAM4E-EK开发板代码解读11——EEPROM - Mcuzone 野芯科技

//使能TWI主模式
[color=Red]void twi_enable_master_mode(Twi *p_twi)[/color]
{
//设置主禁用位和从禁用位
p_twi->TWI_CR = TWI_CR_MSDIS;
p_twi->TWI_CR = TWI_CR_SVDIS;
//设置主使能位
p_twi->TWI_CR = TWI_CR_MSEN;
}
//暂时禁用TWI主控模式
void twi_disable_master_mode(Twi *p_twi)
{
//设置主禁用位
p_twi->TWI_CR = TWI_CR_MSDIS;
}
//初始化TWI模式
如果初始化成功就返回TWI_SUCCESS,否则返回错误代码
uint32_t twi_master_init(Twi *p_twi, const twi_options_t *p_opt)
{
uint32_t status = TWI_SUCCESS;
//关闭TWI中断
p_twi->TWI_IDR = ~0UL;
//虚拟读状态寄存器
p_twi->TWI_SR;
//复位TWI外设
twi_reset(p_twi);
twi_enable_master_mode(p_twi);
//选择速度
if (twi_set_speed(p_twi, p_opt->speed, p_opt->master_clk) == FAIL) {
//所需的速度设置被拒绝
status = TWI_INVALID_ARGUMENT;
}
if (p_opt->smbus == 1) {
p_twi->TWI_CR = TWI_CR_QUICK;
}
return status;
}
//设置I2C总线速度与时钟频率
uint32_t twi_set_speed(Twi *p_twi, uint32_t ul_speed, uint32_t ul_mck)
{
uint32_t ckdiv = 0;
uint32_t c_lh_div;
if (ul_speed > I2C_FAST_MODE_SPEED) {
return FAIL;
}
c_lh_div = ul_mck / (ul_speed * TWI_CLK_DIVIDER) - TWI_CLK_CALC_ARGU;
//cldiv必须适合8位，cldiv必须适合3位
while ((c_lh_div > TWI_CLK_DIV_MAX) && (ckdiv < TWI_CLK_DIV_MIN)) {
//增加时钟分压器
ckdiv++;
//分割cldiv值
c_lh_div /= TWI_CLK_DIVIDER;
}
//设置时钟波形发生器寄存器
p_twi->TWI_CWGR =
TWI_CWGR_CLDIV(c_lh_div) | TWI_CWGR_CHDIV(c_lh_div) |
TWI_CWGR_CKDIV(ckdiv);
return PASS;
}
//测试芯片是否响应给指定的I2C地址
如果找到芯片返回TWI_SUCCESS,否则返回错误代码
uint32_t twi_probe(Twi *p_twi, uint8_t uc_slave_addr)
{
twi_packet_t packet;
uint8_t data = 0;
//发送数据
packet.buffer = &data;
//数据长度
packet.length = 1;
//从芯片地址
packet.chip = (uint32_t) uc_slave_addr;
//芯片内部地址
packet.addr[0] = 0;
//地址长度
packet.addr_length = 0;
//执行主写访问
return (twi_master_write(p_twi, &packet));
}
//内部构造TWI模块地址寄存器字段
TWI模块地址寄存器先发送MSB，尺寸控制哪一个字节是MSB开始
static uint32_t twi_mk_addr(const uint8_t *addr, int len)
{
uint32_t val;
if (len == 0)
return 0;
val = addr[0];
if (len > 1) {
val <<= 8;
val |= addr[1];
}
if (len > 2) {
val <<= 8;
val |= addr[2];
}
return val;
}
//从一个TWI兼容的从设备读取多个字节
在所有数据被读取或出现错误之前，此函数不会返回
如果读取了所有字节，返回TWI_SUCCESS,否则返回错误代码
uint32_t twi_master_read(Twi *p_twi, twi_packet_t *p_packet)
{
uint32_t status, cnt = p_packet->length;
uint8_t *buffer = p_packet->buffer;
//检查参数
if (cnt == 0) {
return TWI_INVALID_ARGUMENT;
}
//设置读取模式，从地址和3个内部地址字节长度
p_twi->TWI_MMR = 0;
p_twi->TWI_MMR = TWI_MMR_MREAD | TWI_MMR_DADR(p_packet->chip) |
((p_packet->addr_length << TWI_MMR_IADRSZ_Pos) &
TWI_MMR_IADRSZ_Msk);
//设置远程芯片的内部地址
p_twi->TWI_IADR = 0;
p_twi->TWI_IADR = twi_mk_addr(p_packet->addr, p_packet->addr_length);
//发送一个开始条件
p_twi->TWI_CR = TWI_CR_START;
while (cnt > 0) {
status = p_twi->TWI_SR;
if (status & TWI_SR_NACK) {
return TWI_RECEIVE_NACK;
}
//判断是否是最后一个字节
if (cnt == 1) {
p_twi->TWI_CR = TWI_CR_STOP;
}
if (!(status & TWI_SR_RXRDY)) {
continue;
}
*buffer++ = p_twi->TWI_RHR;
cnt--;
}
while (!(p_twi->TWI_SR & TWI_SR_TXCOMP)) {
}
p_twi->TWI_SR;
return TWI_SUCCESS;
}
//将多个字节写入一个TWI兼容的从设备
uint32_t twi_master_write(Twi *p_twi, twi_packet_t *p_packet)
{
uint32_t status, cnt = p_packet->length;
uint8_t *buffer = p_packet->buffer;
//检查参数
if (cnt == 0) {
return TWI_INVALID_ARGUMENT;
}
//设置写入模式，从地址和3个内部地址字节长度
p_twi->TWI_MMR = 0;
p_twi->TWI_MMR = TWI_MMR_DADR(p_packet->chip) |
((p_packet->addr_length << TWI_MMR_IADRSZ_Pos) &
TWI_MMR_IADRSZ_Msk);
//设置远程芯片的内部地址
p_twi->TWI_IADR = 0;
p_twi->TWI_IADR = twi_mk_addr(p_packet->addr, p_packet->addr_length);
//发送所有字节
while (cnt > 0) {
status = p_twi->TWI_SR;
if (status & TWI_SR_NACK) {
return TWI_RECEIVE_NACK;
}
if (!(status & TWI_SR_TXRDY)) {
continue;
}
p_twi->TWI_THR = *buffer++;
cnt--;
}
while (1) {
status = p_twi->TWI_SR;
if (status & TWI_SR_NACK) {
return TWI_RECEIVE_NACK;
}
if (status & TWI_SR_TXRDY) {
break;
}
}
p_twi->TWI_CR = TWI_CR_STOP;
while (!(p_twi->TWI_SR & TWI_SR_TXCOMP)) {
}
return TWI_SUCCESS;
}
//使能TWI中断
void twi_enable_interrupt(Twi *p_twi, uint32_t ul_sources)
{
//启用指定的中断
p_twi->TWI_IER = ul_sources;
}
//关闭TWI中断
void twi_disable_interrupt(Twi *p_twi, uint32_t ul_sources)
{
//关闭指定的中断
p_twi->TWI_IDR = ul_sources;
//伪读
p_twi->TWI_SR;
}
//得到TWI中断状态
uint32_t twi_get_interrupt_status(Twi *p_twi)
{
return p_twi->TWI_SR;
}
//读TWI中断掩码
uint32_t twi_get_interrupt_mask(Twi *p_twi)
{
return p_twi->TWI_IMR;
}
//从TWI总线读取一个字节
uint8_t twi_read_byte(Twi *p_twi)
{
return p_twi->TWI_RHR;
}
//向总线上的一个TWI从服务器发送一个字节的数据
void twi_write_byte(Twi *p_twi, uint8_t uc_byte)
{
p_twi->TWI_THR = uc_byte;
}
//使能TWI从模式
void twi_enable_slave_mode(Twi *p_twi)
{
//设置主禁用位和从禁用位
p_twi->TWI_CR = TWI_CR_MSDIS;
p_twi->TWI_CR = TWI_CR_SVDIS;
//设置主使能位
p_twi->TWI_CR = TWI_CR_SVEN;
}
//关闭TWI从模式
void twi_disable_slave_mode(Twi *p_twi)
{
//设置从机禁用位
p_twi->TWI_CR = TWI_CR_SVDIS;
}
//初始化TWI从模式
void twi_slave_init(Twi *p_twi, uint32_t ul_device_addr)
{
//禁用TWI中断
p_twi->TWI_IDR = ~0UL;
p_twi->TWI_SR;
//复位TWI
twi_reset(p_twi);
//在从模式下设置从地址
p_twi->TWI_SMR = TWI_SMR_SADR(ul_device_addr);
//使能从模式
twi_enable_slave_mode(p_twi);
}
//设置TWI从地址
void twi_set_slave_addr(Twi *p_twi, uint32_t ul_device_addr)
{
//设置从地址
p_twi->TWI_SMR = TWI_SMR_SADR(ul_device_addr);
}
//从主服务器读取数据
uint32_t twi_slave_read(Twi *p_twi, uint8_t *p_data)
{
uint32_t status, cnt = 0;
do {
status = p_twi->TWI_SR;
if (status & TWI_SR_SVACC) {
if (!(status & TWI_SR_GACC) &&
((status & (TWI_SR_SVREAD | TWI_SR_RXRDY))
== (TWI_SR_SVREAD | TWI_SR_RXRDY))) {
*p_data++ = (uint8_t) p_twi->TWI_RHR;
cnt++;
}
} else if ((status & (TWI_SR_EOSACC | TWI_SR_TXCOMP))
== (TWI_SR_EOSACC | TWI_SR_TXCOMP)) {
break;
}
} while (1);
return cnt;
}
//将数据写入TWI总线
uint32_t twi_slave_write(Twi *p_twi, uint8_t *p_data)
{
uint32_t status, cnt = 0;
do {
status = p_twi->TWI_SR;
if (status & TWI_SR_SVACC) {
if (!(status & (TWI_SR_GACC | TWI_SR_SVREAD)) &&
(status & TWI_SR_TXRDY)) {
p_twi->TWI_THR = *p_data++;
cnt++;
}
} else if ((status & (TWI_SR_EOSACC | TWI_SR_TXCOMP))
== (TWI_SR_EOSACC | TWI_SR_TXCOMP)) {
break;
}
} while (1);
return cnt;
}
//重置TWI
void twi_reset(Twi *p_twi)
{
//设置SWRST位重置TWI外设
p_twi->TWI_CR = TWI_CR_SWRST;
p_twi->TWI_RHR;
}
//获取TWI PDC基址
Pdc *twi_get_pdc_base(Twi *p_twi)
{
Pdc *p_pdc_base = NULL;
if (p_twi == TWI0) {
p_pdc_base = PDC_TWI0;
}
#ifdef PDC_TWI1
else if (p_twi == TWI1) {
p_pdc_base = PDC_TWI1;
}
#endif
#ifdef PDC_TWI2
else if (p_twi == TWI2) {
p_pdc_base = PDC_TWI2;
}
#endif
else
{
Assert(false);
}
return p_pdc_base;
}
#if SAM4E
//启用\禁用写保护模式
void twi_set_write_protection(Twi *p_twi, bool flag)
{
if (flag) {
p_twi->TWI_WPROT_MODE = TWI_WP_KEY_VALUE | TWI_WPROT_MODE_WPROT;
} else {
p_twi->TWI_WPROT_MODE = TWI_WP_KEY_VALUE;
}
}
//简要读取写入保护状态
void twi_read_write_protection_status(Twi *p_twi, uint32_t *p_status)
{
*p_status = p_twi->TWI_WPROT_STATUS;
}
#endif

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