Si5351时钟芯片控制
Si5351一、SI5351频率计算公式：f(out)=f(pll)/M(x)R(x)f(out) = f(pll) / M(x)R(x)f(out)=f(pll)/M(x)R(x)1、小于150Mhz先设置PLL的频率f(pll)=f(晶振频率)(a+b/c)f(pll) = f(晶振频率)(a + b/c)f(pll)=f(晶振频率)(a+b/c)a+b/c的范围（15 + 0/1048575
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Si5351
一、SI5351频率计算公式：
f(out)=f(pll)/M(x)R(x) f(out) = f(pll) / M(x)R(x) f(out)=f(pll)/M(x)R(x)
1、小于150Mhz
先设置PLL的频率
f(pll)=f(晶振频率)(a+b/c) f(pll) = f(晶振频率)(a + b/c) f(pll)=f(晶振频率)(a+b/c)
a+b/c的范围 （15 + 0/1048575, 90)
a、b、c的设置方法参照文档设置MSNx_P1[17:0]、MSNx_P2[19:0]、MSNx_P3[19:0]寄存器
MSNA_P1[17:0]、MSNA_P2[19:0]、MSNA_P3[19:0]
MSNAP1[17:0]=128∗a+Floor(128∗b/c)−512 MSNA_P1[17:0] = 128 *a+Floor(128* b/c) - 512 MSNAP1[17:0]=128∗a+Floor(128∗b/c)−512
MSNAP2[19:0]=128∗b−c∗Floor(128∗b/c) MSNA_P2[19:0] = 128*b - c*Floor(128* b/c) MSNAP2[19:0]=128∗b−c∗Floor(128∗b/c)
MSNAP3[19:0]=c MSNA_P3[19:0] = c MSNAP3[19:0]=c
再设置Multisynth分频设置寄存器MSx_P1[17:0]、MSx_P2[19:0]、MSx_P3[19:0]
MSAP1[17:0]=128∗a+Floor(128∗b/c)−512 MSA_P1[17:0] = 128 *a+Floor(128* b/c) - 512 MSAP1[17:0]=128∗a+Floor(128∗b/c)−512
MSAP2[19:0]=128∗b−c∗Floor(128∗b/c) MSA_P2[19:0] = 128*b - c*Floor(128* b/c) MSAP2[19:0]=128∗b−c∗Floor(128∗b/c)
MSAP3[19:0]=c MSA_P3[19:0] = c MSAP3[19:0]=c
M(x)=a+b/c M(x) = a + b/c M(x)=a+b/c
M(x)的范围（8 + 1/1048575, 2048)
二、驱动SI5351：
SI5351时钟芯片，通过I2C区控制，SI5351地址在Silabs-Si5351A.pdf文档上可以找到是：0xc0（写数据）0xc1（读数据）；
SI5351设置低频率：通过为Rx_DIV写入适当的设置将其设置为1，2，4，8，… 128。设置此参数可生成低至8kHz的频率；
SI5351使用晶体振荡器时要设置PLL_SRC、XTAL_CL脚；
PLL_SRC,0x00
XTAL_CL,0x80
1、I2C程序
uint32_t I2C_Timeout;
/**
PB6 -------> I2C1 SCL
PB7 -------> I2C1 SDA
**/
void GPIO_Init_Config(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
RCC_AHBPeriphClockCmd(RCC_AHBPeriph_GPIOB, ENABLE);
GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6 | GPIO_Pin_7;
GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_UP;
GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
GPIO_Init(GPIOB, &GPIO_InitStructure);
GPIO_PinAFConfig(GPIOB, GPIO_PinSource6, GPIO_AF_1);
GPIO_PinAFConfig(GPIOB, GPIO_PinSource7, GPIO_AF_1);
}
void I2C1_Init_Config(void)
{
I2C_InitTypeDef I2C_InitStructure;
I2CMaster_RCC_Configuration();
RCC_APB1PeriphResetCmd(RCC_APB1Periph_I2C1, ENABLE);
RCC_APB1PeriphResetCmd(RCC_APB1Periph_I2C1, DISABLE);
GPIO_Init_Config();
RCC_APB2PeriphClockCmd(RCC_APB2Periph_SYSCFG, ENABLE);
RCC_I2CCLKConfig(RCC_I2C1CLK_SYSCLK);
RCC_APB1PeriphClockCmd(RCC_APB1Periph_I2C1, ENABLE);
I2C_InitStructure.I2C_Mode = I2C_Mode_I2C;
I2C_InitStructure.I2C_AcknowledgedAddress = I2C_AcknowledgedAddress_7bit;
I2C_InitStructure.I2C_AnalogFilter = I2C_AnalogFilter_Enable;
I2C_InitStructure.I2C_DigitalFilter = 0x01;
I2C_InitStructure.I2C_OwnAddress1 = 0x00;
I2C_InitStructure.I2C_Ack = I2C_Ack_Enable;
I2C_InitStructure.I2C_Timing = 0x30E32E44;
I2C_Init(I2C1, &I2C_InitStructure);
I2C_Cmd(I2C1, ENABLE);
I2CMaster_NVIC_Configuration();
//I2C_ITConfig();
}
void I2CMaster_RCC_Configuration(void)
{
/* Enable peripheral clocks --------------------------------------------------*/
RCC_APB1PeriphClockCmd(RCC_APB1Periph_I2C1, ENABLE);
}
void I2CMaster_NVIC_Configuration(void)
{
NVIC_InitTypeDef NVIC_InitStructure;
NVIC_InitStructure.NVIC_IRQChannel = I2C1_IRQn;
NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE;
NVIC_InitStructure.NVIC_IRQChannelPriority = 0;
NVIC_Init(&NVIC_InitStructure);
}
I2C_Status I2C_Read_NBytes(uint8_t driver_Addr, uint8_t number_Bytes, uint8_t *read_Buffer)
{
uint8_t read_Num;
I2C_Timeout = I2C_TIMEOUT;
while(I2C_GetFlagStatus(I2C1, I2C_FLAG_BUSY) != RESET)
{
if((I2C_Timeout--) == 0)
{
return I2C_FAIL;
}
}
I2C_TransferHandling(I2C1, driver_Addr, 1, I2C_SoftEnd_Mode, I2C_Generate_Start_Write);
I2C_Timeout = I2C_TIMEOUT;
while(I2C_GetFlagStatus(I2C1, I2C_FLAG_TXIS) == RESET)
{
if((I2C_Timeout--) == 0)
{
return I2C_FAIL;
}
}
I2C_SendData(I2C1, 0Xc0);
I2C_Timeout = I2C_TIMEOUT;
while(I2C_GetFlagStatus(I2C1, I2C_FLAG_TC) == RESET)
{
if((I2C_Timeout--) == 0)
{
return I2C_FAIL;
}
}
I2C_TransferHandling(I2C1, driver_Addr, number_Bytes, I2C_AutoEnd_Mode, I2C_Generate_Start_Read);
for(read_Num = 0; read_Num < number_Bytes; read_Num++)
{
I2C_Timeout = I2C_TIMEOUT;
while(I2C_GetFlagStatus(I2C1, I2C_FLAG_RXNE) == RESET)
{
if((I2C_Timeout--) == 0)
{
return I2C_FAIL;
}
}
read_Buffer[read_Num] = I2C_ReceiveData(I2C1);
}
I2C_Timeout = I2C_TIMEOUT;
while(I2C_GetFlagStatus(I2C1, I2C_FLAG_STOPF) == RESET)
{
if((I2C_Timeout--) == 0)
{
return I2C_FAIL;
}
}
return I2C_OK;
}
I2C_Status I2C_Write_NBytes(uint8_t start_Addr, uint8_t write_Buffer)
{
uint8_t write_Num;
uint8_t number_Bytes = 1;
I2C_Timeout = I2C_TIMEOUT;
while(I2C_GetFlagStatus(I2C1, I2C_FLAG_BUSY) != RESET)
{
if((I2C_Timeout--) == 0)
{
return I2C_FAIL;
}
}
I2C_TransferHandling(I2C1, 0xC0, 1, I2C_Reload_Mode, I2C_Generate_Start_Write);
I2C_Timeout = I2C_TIMEOUT;
while(I2C_GetFlagStatus(I2C1, I2C_FLAG_TXIS) == RESET)
{
if((I2C_Timeout--) == 0)
{
return I2C_FAIL;
}
}
I2C_SendData(I2C1, start_Addr);
I2C_Timeout = I2C_TIMEOUT;
while(I2C_GetFlagStatus(I2C1, I2C_FLAG_TCR) == RESET)
{
if((I2C_Timeout--) == 0)
{
return I2C_FAIL;
}
}
I2C_TransferHandling(I2C1, 0xC0, number_Bytes, I2C_AutoEnd_Mode, I2C_No_StartStop);
for(write_Num = 0; write_Num < number_Bytes; write_Num++)
{
I2C_Timeout = I2C_TIMEOUT;
while(I2C_GetFlagStatus(I2C1, I2C_FLAG_TXIS) == RESET)
{
if((I2C_Timeout--) == 0)
{
return I2C_FAIL;
}
}
I2C_SendData(I2C1, write_Buffer);
}
I2C_Timeout = I2C_TIMEOUT;
while(I2C_GetFlagStatus(I2C1, I2C_FLAG_STOPF) == RESET)
{
if((I2C_Timeout--) == 0)
{
return I2C_FAIL;
}
}
return I2C_OK;
}
2、Si5351程序
//设置PPL时钟
// 参数： pll寄存器 mult a num b denom c
void setupPLL(uint8_t pll, uint8_t mult, uint32_t num, uint32_t denom)
{
uint32_t P1; // PLL config register P1
uint32_t P2; // PLL config register P2
uint32_t P3; // PLL config register P3
P1 = (uint32_t)(128 * ((float)num / (float)denom));
P1 = (uint32_t)(128 * (uint32_t)(mult) + P1 - 512);
P2 = (uint32_t)(128 * ((float)num / (float)denom));
P2 = (uint32_t)(128 * num - denom * P2);
P3 = denom;
I2C_Write_NBytes(pll + 0, (P3 >> 8)& 0xFF); //MSN_P3[15:8]
I2C_Write_NBytes(pll + 1, (P3 & 0xFF)); //MSN_P3[7:0]
I2C_Write_NBytes(pll + 2, (P1 >> 16)& 0x03); //MSN_P1[17:16]
I2C_Write_NBytes(pll + 3, (P1 >> 8) & 0xFF); //MSN_P1[15:8]
I2C_Write_NBytes(pll + 4, (P1 & 0xFF)); //MSN_P1[7:0]
I2C_Write_NBytes(pll + 5, ((P3 >> 12) & 0xF0) | ((P2 >> 16) & 0x0F)); //MSN_P3[19:16] + MSN_P2[19:16]
I2C_Write_NBytes(pll + 6, (P2 >> 8) & 0xFF); //MSN_P2[15:8]
I2C_Write_NBytes(pll + 7, (P2 & 0xFF)); //MSN_P2[7:0]
}
void Multisynth(uint8_t synth, uint8_t a, uint32_t b, uint32_t c, uint8_t rDiv)
{
uint32_t P1; // Synth config register P1
uint32_t P2; // Synth config register P2
uint32_t P3; // Synth config register P3
P1 = (uint32_t)(128 * ((float)b / (float)c));
P1 = (uint32_t)(128 * (uint32_t)(a) + P1 - 512);
P2 = (uint32_t)(128 * ((float)b / (float)c));
P2 = (uint32_t)(128 * b - c * P2);
P3 = c;
I2C_Write_NBytes(synth + 0, (P3 >> 8) & 0xFF); //MS_P3[15:8]
I2C_Write_NBytes(synth + 1, (P3 & 0xFF)); //MS_P3[7:0]
I2C_Write_NBytes(synth + 2, ((P1 >> 16) & 0x03) | rDiv); //MS_P1[17:16]
I2C_Write_NBytes(synth + 3, (P1 >> 8) & 0xFF); //MS_P1[15:8]
I2C_Write_NBytes(synth + 4, (P1 & 0xFF)); //MS_P1[7:0]
I2C_Write_NBytes(synth + 5, ((P3 >> 12) & 0xF0) | ((P2 >> 16) & 0x0F)); //MS_P3[19:16] + MS_P2[19:16]
I2C_Write_NBytes(synth + 6, (P2 >> 8) & 0xFF); //MS_P2[15:8]
I2C_Write_NBytes(synth + 7, (P2 & 0xFF)); //MS_P2[7:0]
}
//设置时钟频率
void si5351aSetFrequency(uint32_t frequency , uint8_t Chanal )
{
I2C_Write_NBytes(PLL_SRC,0x00);
I2C_Write_NBytes(XTAL_CL,0x80);
if ( Chanal == 1 ){
//I2C_Write_NBytes(FBB_INT , 0x40); //整数模式
setupPLL(SI_SYNTH_PLL_B, 1, 0, 10); //设置锁相环与倍增系数计算
Multisynth(SI_SYNTH_MS_1, 100, 1036, 10, SI_R_DIV_32);
I2C_Write_NBytes(SI_PLL_RESET,0xA0);
I2C_Write_NBytes(SI_CLK1_CONTROL, 0x4F|SI_CLK_SRC_PLL_B);
}
if (frequency == Fre_45M)
{
if( Chanal == 0 )
{
setupPLL(SI_SYNTH_PLL_A, 20, 0, 10); //设置锁相环与倍增系数计算
Multisynth(SI_SYNTH_MS_0, 12, 0, 10, SI_R_DIV_1); //设置MultiSynth分配器0分计算。最后R分裂阶段可以除以2的幂,从1 . . 128。如果想在1兆赫兹以下输出,你必须使用,最后R分裂阶段
I2C_Write_NBytes(SI_PLL_RESET,0xA0); //重置锁相环。这将导致输出的故障。对于小的变化参数,不需要复位锁相环,没有故障
I2C_Write_NBytes(SI_CLK0_CONTROL, 0x4F|SI_CLK_SRC_PLL_A); //最后打开CLK0输出(0 x4f)并设置MultiSynth0是锁相环的输入
}
}
}
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